Re: Exceptions in MINA

[Emmanuel Lecharny]

Michael Ossareh wrote:

On Mon, Jun 8, 2009 at 3:10 PM, Emmanuel Lecharnyelecha...@apache.org wrote:
  

Michael Ossareh wrote:


On Mon, Jun 8, 2009 at 2:13 PM, David Rosenstrauchdar...@darose.net
wrote:

  

Michael Ossareh wrote:



In the case above the code in messageReceived() cannot trigger
assertion failures, the exception they throw is trapped by the
framework and JUnit thinks the test passed. I'm using Assert.fail()
because the test I'm doing isn't part of JUnit's base tests (though I
understand I should start checking out the hamcrest matchers for my
tests:

http://stackoverflow.com/questions/958460/creating-a-assertclass-method-in-junit
) however using normal assertion fails suffer the same issue, for
example assertEquals(1, 2) results in the test passing beacause junit
doesn't ever see the exception.

Clearly you'll see the power of this type of testing, the 20 or tests
I have to write are all structured the same. Connect client to server,
either client or server send data, ensure data is rendered same on the
receiving side.

I'm midway through building a solution to this, however some of it
really reinventing the wheel and all because
IoHandlerAdapter.messageReceived / sessionOpened / sessionCreated all
throw Exception and/or the framework doesn't allow the ability to
distinguish different Exceptions from this layer.

mike


  

A couple of suggestions:

1) I'd think you really shouldn't need to go through the whole process of
fully starting up the server (with a socket listener listening on a port)
and a client (opening a socket to the server) just to do testing.   I
don't
know your code so well so perhaps I'm wrong here.  But I'd think it
should
be sufficient to just *simulate* network communication by using a
DummySession and sending a message down the server's filter chain and
seeing
what response - or lack thereof - gets generated.

2) If you follow along with that approach, then you won't be in the
situation where your client is performing assertions inside the
messageReceived method (which are obviously getting swallowed).  If you
look
carefully at the code I posted, you'll see that what I'm doing is to add
an
OutputListener - a class that I use only to assist with testing - at
the
end of my filter chain when I test.  The output listener, true to its
name,
listens to whatever output/response the server's filter chain processing
generates, and saves it.  Once that whole server filter chain interaction
is
complete, and I've saved the output from my communication with the
server, only THEN do I go about issuing Asserts to verify that the
output
was what I expected.  And since these asserts get done outside of the
MINA
filter chain processing they never get swallowed.


Bottom line:  I think you can do any type of JUnit testing you want
against
your MINA server, but you need to write your tests differently.

HTH,

DR




Hi David,

Thanks for your feedback. I noted your example and my reference to
solution to this looks not to dissimilar from what you're doing
(except I don't want to change the filter chain for fear of creating a
difference between prod and dev). The same goes for dummy session. As
I get more to grips with MINA I'm sure my assertions as to how to
build the tests will change.

  

I would add to the very sensitive proposals David have suggested that
whatever you do in your unit tests, trying to keep them close to what you
will have in prod by simulating the full stack (ie, with sockets and server)
is probably impossible : it will just test that the loopback interface works
well, with time conditions totally different to what you will have in prod
anyway.



This is a valid point for sure.

In particular I'm trying to test some decoders and encoders that I've
written to implement a custom binary protocol. It wasn't clear to me,
and I appreciate that MINA is work in progress, how to get an entity
to send an object through a filter chain, and then another entity
decode that object.

As an easier way of doing this I decided to fire up a server and a
client. As far as my testing goes I now have a nice black box
solution, the server and client deal with call backs where the
assertions are trapped in the case of a failure and reported back once
outside of the MINA framework.

  

This is what is difficult when it comes to test a server : unit tests are
just good enough to check the internal logic (ie, the encoder/decoder, the
handler), but you need to build a bench with a real server, real injectors,
etc.

Note that testing your application with real sockets is also good to have,
as you may encounter some weird conditions too.

Thanks for using MINA, btw !



I'm extremely thankful for MINA! A number of years ago I tried to
write an opensource java dhcpd - the point being to have web service
calls at particular parts of the state machine to do things like mac
address authentication, etc. Now with MINA I'm sure I can ressurect
that 

Re: MINA and threads

[Emmanuel Lecharny]

gonzalo diethelm wrote:

Although not strictly necessary, I would have the expectation that,
since MINA is based on NIO, it should be possible to build a single
executable that listens on a port and connects to itself on that port,
all from a single thread. Is this possible at all?
  
No. As soon as you create an Acceptor, it spawns a new thread. Then as 
soon as you accep an incoming connection, at least one new thread is 
created to process the connection.


What you see in the logs is just plain normal The Main thread may ends, 
but as you have at least one more existing thread.




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Re: MINA and threads

[Emmanuel Lecharny]

gonzalo diethelm wrote:

Although not strictly necessary, I would have the expectation that,
since MINA is based on NIO, it should be possible to build a single
executable that listens on a port and connects to itself on that
  

port,
  

all from a single thread. Is this possible at all?
  

No. As soon as you create an Acceptor, it spawns a new thread. Then as
soon as you accept an incoming connection, at least one new thread is
created to process the connection.

What you see in the logs is just plain normal The Main thread may end,
but as you have at least one more existing thread.



Is this common practice in the Java NIO world? Because on the C/C++
side, there are good reasons why one would avoid using threads at all
and move toward a non-blocking approach, even if it is more difficult to
implement. Admittedly, using threads in Java may be more of a
non-brainer; I admit that I can't help but feel a little disappointed
that it is not possible to do all of this in MINA on a single thread (if
one so wanted). Again, maybe I am too influenced by my previous C++
experience.
  
Implementing everything with a single thread means that we use one 
selector to handle the accept and the session. possible, but then, why 
using MINA ? You can do that with a simple SocketServer, a selector and 
a few glue around it.


The idea with MINA was to create a scalable NIO framework, easy enough 
to use. Doing that on a single thread would kill the initial design...



Let me ask this in another way: could I build the mentioned example
(single executable that listens on a port and connects to itself on that
port, all from a single thread) by programming directly to Java NIO,
totally bypassing MINA?
  

I guess so.

If the answer to the above is yes, then it would seem that MINA forces
the choice of a concurrency / processing model (one thread per
connection). Keep in mind that there is a whole gamut of choices here,
ranging from single thread, non-blocking to thread per connection,
blocking at the extremes, including the thread-pool, blocking or
non-blocking right in the middle.
  
Well, it's impossible to design a system which fits all the needs. Also 
I don't really see the problem you are trying to fix with this 'one 
thread to manage everything'. You are the first person on the mailing 
list in 3 years to expose such a need. Do you have some technical 
constraints that limit you to using only one thread ?



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Re: MINA and threads

[Emmanuel Lecharny]

gonzalo diethelm wrote:

Implementing everything with a single thread means that we use one
selector to handle the accept and the session. possible, but then, why
using MINA ? You can do that with a simple SocketServer, a selector and
a few glue around it.

The idea with MINA was to create a scalable NIO framework, easy enough
to use. Doing that on a single thread would kill the initial design...


...
  

Well, it's impossible to design a system which fits all the needs. Also
I don't really see the problem you are trying to fix with this 'one
thread to manage everything'. You are the first person on the mailing
list in 3 years to expose such a need. Do you have some technical
constraints that limit you to using only one thread ?



More than a need, I am trying to grasp the design objectives for MINA. I come 
from a C++ experience, where sometimes you will want to choose to have 
everything running in one single thread, doing all the multiplexing yourself, 
and sometimes you will want to use threads, maybe associating one thread with 
one connection, or pooling your threads because their creation and destruction 
can be expensive.
  
Basically, MINA was designed as a SEDA based framework (even if this 
target has been lost in the meantime, somehow ...). Sicne then, it has 
aevolved a bit.


The internal design was done in otder to decouple the concerns as much 
as possible. So you have a thread handling incoming connections, N 
processor, each of them having a selector, to process the incoming and 
outgoing events (read and write) each processor being associated with a 
thread, and as you can add an Executor filter in the chain, you can also 
have N threads to handle the load (this construction is the only 
remaining SEDA flavor in the framework).


All those threads are intended to offer a better scalability, but that 
has still to be proven :)


But more than that, and many persons are questioning the scalability, 
it's a damn simple framework when it comes to quickly design a server, 
letting you to focus on what matters : the codec and the handler.


At some point in the future, though, considering other aspects than ease 
of use, we may have to tune the design to allow one user to select the 
best solution. We are far from this point ... :/

I have used the C++ ACE framework in the past, and it does give the designer 
the choice regarding which threading model to follow. Mind you, I am NOT saying 
that ACE is better than MINA, or that C++ is better than Java. I WANT to use 
MINA; I also would like to learn the extent of my choices / constraints set by 
the framework, and the reasons why it provides those choices /constraints, and 
not others.
  


I hope I brought a bit of light in the dark :)

fell free to ask more !

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Emmanuel Lécharny
www.iktek.com
directory.apache.org

Re: MINA and threads

[Emmanuel Lecharny]

Christopher Popp wrote:

I think you might be confusing the thread model a bit...with MINA you don't 
need a thread per client.  There is one thread listening which handles 
accepting connections.  There are then a configurable pool of I/O handling 
threads (defaulting to # of cores +1) which handle incoming messages.  
Optionally, you can specify an ExecutorFilter in your filter chain if you want 
another pool of threads available later in case you expect this would benefit 
your application logic.

So...at a minimum, you could configure MINA to only use two threads (one for accepting, and one for processing I/O), and have that handle any number of connected clients.  
  
I would say three : main, the IoAcceptor thread and a IoProcessor 
thread. Not a big difference though :)


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Re: Server and Client at the same time

[Emmanuel Lecharny]

gonzalo diethelm wrote:

From: gonzalo diethelm [mailto:gdieth...@dcv.cl]
Sent: Thursday 11 Jun 2009 10:59
To: users@mina.apache.org
Subject: Server and Client at the same time

Hello again. I would like to gather opinions on how to implement a


proof
  

of concept for my requirements.

 
[snip]


I must apologize for seemingly asking a repeated question. I understand
now that the Proxy example is a good way to approach my requirements,
and this had already been answered previously. It is just that I do not
see these requirements as implementing a proxy, I see them more as
implementing nodes in a grid; hence my error.
  
The Proxy is just an example with a server processing incoming requests 
and pushing them to a client. What's different with your grid approach, 
whatever it can be ? ( so far, I don't really see where you are heading 
to...)

Also, for full disclosure: I posted a similar question on the Netty
mailing list. I know next to nothing about MINA and Netty, and am trying
to compare them for my purposes.
  

Np at all. You should also have a look at Grizzly.

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Re: Clarification on use of IOBuffer

[Emmanuel Lecharny]

Yasdnil Zbib wrote:

Hi

I am just starting to get to grips with MINA 2.0, and have a question about the 
use of IOBuffer, which I hope someone can help me with.
Apologies up front for the newbie status of this:

When a ProtocolDecoder recieves an IOBuffer to decode I have read that my 
incoming message may not have been fully written,
and it is up to the decoder to handle this, druing the translation to my POJO.
  

right

But, if my message has been fully written - is the buffer likely tohave another 
message in it ?
  

absolutely


For example: say the IOBuffer is 650 bytes in length (and assume 
non-auto-expanding).
My inbound message is 300 bytes.

Once I have read the 300 bytes and converted to a POJO - will I ever see a 
second message in the IOBuffer, following on ?
  

you may have another message.

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Re: ProtocolDecoderException: java.nio.charset.MalformedInputException encountered in Apache mina 1.1.7

[Emmanuel Lecharny]

lasith haputhanthiri wrote:

Exception caught: org.apache.mina.filter.codec.ProtocolDecoderException:
java.nio.charset.MalformedInputException: Input length = 1 (Hexdump: 33 1C
33 1C 30 1C 30 1C 30 1C 30 1C 41 53 30 30 30 30 30 33 32 36 39 01 42 46 47
42 01 22 30 01 48 30 01 49 41 44 53 4D 01 4A 41 45 44 01 4B 32 01 4C 31 01
4D 35 30 30 01 4E 31 34 2E 30 01 4F 30 01 52 30 01 57 58 01 67 36 01 68 34
37 31 37 01 75 6E 75 6C 6C 32 01 79 44 42 46 53 5F 54 45 53 54 01 7A 30 01
34 39 2E 30 01 32 31 39 37 30 30 31 01 36 31 2E 30 01 39 30 01 21 30 01 7C
30 2E 30 01 23 30 01 2C 30 01 A7 01 0A)
^^--- A7 is not a valid UTF-8 
encoded value.


See http://en.wikipedia.org/wiki/UTF-8, section Description.

Check your client.

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Emmanuel Lécharny
www.iktek.com
directory.apache.org

Re: Logging filter oddity

[Emmanuel Lecharny]

boB Gage wrote:
Emmanuel, you're right I should be annoyed at the previous 
designer that tied our non-volunteer project with strictly defined 
deadlines to a volunteer-developed library tool set; not at the 
volunteers who never actually committed to support anything.
well, it's always the same story : even if you have selected a close 
source API, even if you have paid a huge amount of money for it, it 
could still contain bugs, and you could still be stuck.


We are really trying to do our best to deliver the best quality 
software, and it's not easy. Julien, for instance, is using MINA with 
the serial layer (he coded it) for its own usage. Obviously, he is ready 
to pay the price for it (ie, time on his own hours), not only because he 
needs it, but also because he sees the immediate benefits he can get 
from such a piece of software : a community around it which can help if 
he gets stuck in some part of the code.


If I can send a message to all the users : it's really easy, and 
rewarding, to become a committer. It's a matter of participating by 
providing patches.


Also note that we never spread the wrong signal that MINA 2.0 was ready. 
It's still a milestone, and designed as unstable. Yes, I know, it takes 
forever to get a release out...


Problem is I've got umpteen different things that have to be fixed and 
added at our level of the application and this is neither the first, 
nor even the only active issue in our code likely caused by Mina.
I've hesitated to mention the other active issue, so as to not muddy 
the waters -- one problem at a time.  :-)

Well, sometime, it's better to get the whole picture :)


Unfortunately, I don't think the designer who decided on Mina realized 
that we were taking it places it apparently has never been before...   
What we needed was a cross-platform answer to a serial application; 
the tool he chose was Mina, whose serial-side is apparently new and 
I'm finding not overly bug-free.   Our application is being used in a 
health care setting so should be as bullet-proof as possible.

This is what we are targetting too. A slipery path, too...


I'll have to ask my bosses about patches.   It's really two 
questions.  Do they want to pay me to fix Mina library?   If so, are 
they willing to then give away those fixes to the community at large?  
I'm on someone else's payroll, so I don't make those decisions.

You have two options here :
- you can fork MINA, if for any legal reasons you can't or don't want to 
share the patches,

- or you can grant the patches to The ASF

I understand that's not as simple as willing to contribute to the project.



boB

PS...   Okay, so say I do have to dig and fix this myself.How 
would I confirm my Mina svn repository matches the M4 code I'm using 
before I muck around with it?   Or do I have to update to the latest 
Mina code first?   (M2 to M4 got ugly; M4 to M5 looked horrible and 
was quickly reversed, been waiting for the real release ever since)
Let be clear : M4 sucks, M5 is even worst. M6 is way better. Trunk will 
be (hopefully) even better. In any case, you can pick the milestone you 
prefer, in the tags/ directory : it's frozen. When you would like to 
move to a more recent version (say, M7 when ready), it's just a matter 
to merge your modification into the trunk. as we aren't modifying the 
code a lot atm (we are just in bug fix mode), that should not be a problem.


Hope it helps (a bit ;)

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www.iktek.com
directory.apache.org

Re: Logging filter oddity

[Emmanuel Lecharny]

Christopher Popp wrote:

Yep, after taking the second glance at it, it looks like the message sent event 
should occur every time the write occurs later on in the method.

I just took a glance quick, and it looks like they tag each of their releases, 
so you should be able to checkout the 2.0.0-M4 tagged version and get a 
suitable codebase to try from.  It looks like that code hasn't changed between 
M4 and now:

http://svn.apache.org/viewvc/mina/tags/2.0.0-M4/transport-serial/src/main/java/org/apache/mina/transport/serial/SerialSessionImpl.java?revision=724773
  


I urge you to use M6. M4 is using a non-thread safe Circular queue 
causing to some message loss when under heavy load, M5 ExecutorFilter is 
broken. All this has been fixed in M6, so far.


In any case, serial hasen't change since M4.

Christopher

  
H, I see the code in question, but I'm not sure I can test it.I've got an old svn checkout, that I thought was M4-ish in timeframe.   But when I build it it's calling itself RC2.  


That's a mistake we made. Just a bad tag.

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Re: JIRA

[Emmanuel Lecharny]

boB Gage wrote:
Have entered JIRA tickets with details of the recent issues I've 
brought to the list.


DIRMINA-719 --Serial Filter Chain Broken For Outbound Data

DIRMINA-720 -- Hardware Flow Control Disables Serial Port on Windows 
Platform

Saw that. I have added a comment on 719


I have also updated our project to use 2.0.0-M6.   I have not (yet?) 
noticed any differences in behaviour.

At least, it's not worst :)


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Re: NIO performance

[Emmanuel Lecharny]

David Rosenstrauch wrote:

David Rosenstrauch wrote:

Mark Webb wrote:

This was discussed in length on this mailing list back when the
article was posted.  I vaguely remember the discussion, other than it
happened.

Checking the archives should give you what you are looking for.

--Mark


Ah, didn't realize.  Will go RTFM.  Sorry for the noise.

DR


Tried to search through the gmane archives (as well as my local disk 
archives) on both Tyma and mailinator but didn't turn up anything. 
Would you happen a pointer?

http://www.mail-archive.com/d...@mina.apache.org/msg07525.html

Dev list.

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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

Chowdhury, Shubhankar [WHQKA] wrote:

o o the whole format got garbled - let me try in plain text
--
--

This might be a very dumb post but please help.  


I have already used MINA for a few projects mainly using the
CumulativeProtocolDecoder and RequestResponseFilter for the client
applications and using TextlineCodec for a few server instances. But my
next attempt is a bit complex where the data that comes is a structured
data of variable length basically of the following format-

Offset-LengthInByte-FieldName
--
0-8-application_id
8-2-Version
10-2-Type
12-2-message_id_number
14-2-Data_length
16-4-Reserved
20-data_length-Data

The application would be a server listening to a port (TCP) and also
would return back some response based on the type field. So the client
would initiate by sending a login-request - in response we have to
send accept or reject, then the data would be flowing, then log-out,
keep-alive etc and all of them would follow the above structure.

 


How do I handle this using MINA? Is there anyway I can use the
CumulativeProtocolDecoder?
  
Actually, it will easy. As you know the length of your message, it's 
just a matter of storing what has already been received in the session, 
until you got all the message.


The decoder must be able to stop in the middle of an int, for instance, 
which is not that complicated, assuming that an int is a fixed size 
element. You just have to check that you have 4 bytes available in the 
buffer to decode the int, otherwise, you just store the buffer in the 
session, and wait for the next bytes to come.


Sounds complicated, but it's not.

The real issue is if you have very long messages : in this case, you may 
want to stream to a file the incoming data, to avoid a OOM.


When you have received everything, then you can push the resulting 
eleme,t to your handler (if of course you built a data structure on the 
fly).


Hope it helps.

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Emmanuel Lécharny
www.iktek.com
directory.apache.org

Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

David Rosenstrauch wrote:
I do something similar, using a binary protocol where messages vary in 
length based on data-length values in the message.  And yes, I use a 
custom subclass of CumulativeProtocolDecoder for this.


The code's a bit ugly, but it works.  Essentially your decoder needs 
to handle 3 possible cases:


* full, syntactically correct message received
* part of a syntactically correct message received, and
* syntactically incorrect message received


I would add a forth case :
* more than one complete message in a single buffer.

In this case, you have to loop until you have decoded all the messages, 
calling the next filter for each decoded message.


This is what we do in Apache Directory to decode LDAP requests.

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Emmanuel Lécharny
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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

Chowdhury, Shubhankar [WHQKA] wrote:
Thanks Emanuel but actually I the message lengths vary in each message - that's part of the message itself. If you see the message format 14-2-Data_length - so starting at 14th byte and I will have an short value giving me the data length. 

  
This is cover but my explaination : as soon as you are able to decode 
the length, you know how many bytes to get to have a complete portion of 
your full message. The only problem is that the length, stored as four 
bytes (if its an int, for instance), has to be decoded itself. But at 
least, you know that you expect 4 bytes to decode an int.
Once I receive the whole message then only I can apply the byte off-sets to extract the message body and header etc. 
This is not the right way to decode your message. Here, you assume you 
already have received the full message. Just consider that your message 
can arrive byte by byte, you just have to make your decoder happy with 
that. Once you cand deal with such a flow of separated bytes, every 
other cases are just simple.




but with in.available() I would have to know the message length before hand 
isn't it? Am I missing something?
  
yep. You are missing the fact that you can decode what you have already 
received.

Thanks,
Shubhankar
847-700-4452
-Original Message-
From: Emmanuel Lecharny [mailto:elecha...@gmail.com] On Behalf Of Emmanuel 
Lecharny
Sent: Friday, June 19, 2009 5:46 PM
To: users@mina.apache.org
Subject: Re: Handling variable length request/response in MINA

Chowdhury, Shubhankar [WHQKA] wrote:
  

o o the whole format got garbled - let me try in plain text
--
--

This might be a very dumb post but please help.  


I have already used MINA for a few projects mainly using the
CumulativeProtocolDecoder and RequestResponseFilter for the client
applications and using TextlineCodec for a few server instances. But my
next attempt is a bit complex where the data that comes is a structured
data of variable length basically of the following format-

Offset-LengthInByte-FieldName
--
0-8-application_id
8-2-Version
10-2-Type
12-2-message_id_number
14-2-Data_length
16-4-Reserved
20-data_length-Data

The application would be a server listening to a port (TCP) and also
would return back some response based on the type field. So the client
would initiate by sending a login-request - in response we have to
send accept or reject, then the data would be flowing, then log-out,
keep-alive etc and all of them would follow the above structure.

 


How do I handle this using MINA? Is there anyway I can use the
CumulativeProtocolDecoder?
  

Actually, it will easy. As you know the length of your message, it's 
just a matter of storing what has already been received in the session, 
until you got all the message.


The decoder must be able to stop in the middle of an int, for instance, 
which is not that complicated, assuming that an int is a fixed size 
element. You just have to check that you have 4 bytes available in the 
buffer to decode the int, otherwise, you just store the buffer in the 
session, and wait for the next bytes to come.


Sounds complicated, but it's not.

The real issue is if you have very long messages : in this case, you may 
want to stream to a file the incoming data, to avoid a OOM.


When you have received everything, then you can push the resulting 
eleme,t to your handler (if of course you built a data structure on the 
fly).


Hope it helps.

  



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cordialement, regards,
Emmanuel Lécharny
www.iktek.com
directory.apache.org

Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

David Rosenstrauch wrote:


I would add a forth case :
* more than one complete message in a single buffer.

In this case, you have to loop until you have decoded all the 
messages, calling the next filter for each decoded message.


This is what we do in Apache Directory to decode LDAP requests.


Hmmm ... I might not actually be handling this case.  I'll have to 
check my code.

I just mentionned it because we have been hit by this problem ;)


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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

David Rosenstrauch wrote:

David Rosenstrauch wrote:

Emmanuel Lecharny wrote:

I would add a forth case :
* more than one complete message in a single buffer.

In this case, you have to loop until you have decoded all the 
messages, calling the next filter for each decoded message.


This is what we do in Apache Directory to decode LDAP requests.


Hmmm ... I might not actually be handling this case.  I'll have to 
check my code.


Thanks much for the heads up.

DR


Question:

So say in my decoder I do as follows:

public class BinaryProtocolDecoder extends CumulativeProtocolDecoder {
protected boolean doDecode(IoSession session, IoBuffer in, 
ProtocolDecoderOutput out) {

...
MyMessage msg = decodeOneMessage(in);
return true;
}
}


i.e., I decode one message from out of the buffer, and leave any 
remaining bytes that are part of the next message left unread in the 
buffer.


Are those remaining bytes from the next message lost?  And if they're 
not lost, will the CumulativeProtocolDecoder then immediately call my 
doDecode method again to try to decode that message?
They won't be lost, it's just that the buffer will keep them until it 
receives more bytes. It has a bad side effect that you may wait forever 
if you receive 3 messages in two byte buffer :
- the first message will be processed, and the first part of the second 
message will remain in the buffer
- when receiving the second part of the second message plus the third 
message, you will process the second message, and the third will remain 
for ever in the buffer (until the session is killed)


DR




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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

Yongxing Wang wrote:
If not implicitly covered in the case of more than one complete message in a single buffer, we also need to deal with the case where a sing buffer contains several complete messages AND an incomplete one. 
  


if fact, all the cases are listed here :
* a buffer with an incomplet message
* a buffer with a message, nothing less, nothing more
* a buffer with N complete messages, nothing more
* a buffer with N complete messages, and some extra bytes.

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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

David Rosenstrauch wrote:


DR


Hmmm ... yeah, that's a problem.  I'll have to fix this.

Thanks for the heads up.


Just keep me informed if this is not anymore a problem...

May be we should document this kind of decoding on the web site too... 
It can e helpfull !


DR




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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

Yongxing Wang wrote:

I wrote a simple unit test case where one single buffer contains two messages, 
using the DummySession. After calling decode, it delivers me two messages:

  IoBuffer in = IoBuffer.wrap(bytesData); = contains two encoded msgs
  decoder.decode(session, in, session.getDecoderOutput());
  assertEquals(2, session.getDecoderOutputQueue().size());
 
Also, looking at the CumulativeProtocolDecoder(which is one I am using),


  for (;;) {
 int oldPos = buf.position();
 boolean decoded = doDecode(session, buf, out);
 if (decoded) {
 if (buf.position() == oldPos) {
throw new IllegalStateException(
doDecode() can't return true when buffer is not 
consumed.);
 }

   if (!buf.hasRemaining()) {
  break;
   }
 } else {
 break;
 }
  }

doDecode will be called again if there are any remaining bytes in the event of successfully decoding one message If I am not terribly wrong, David, your algorithm is fine. 
  


Thanks a lot for having checked !

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Re: Handling variable length request/response in MINA

[Emmanuel Lecharny]

Maarten Bosteels wrote:

It's in the javadocs:  doDecode() is invoked repeatedly until it returns
false 

So there is no need to have a loop in your doDecode implementation for
decoding multiple messages.

http://mina.apache.org/report/trunk/apidocs/org/apache/mina/filter/codec/CumulativeProtocolDecoder.html#doDecode(org.apache.mina.core.session.IoSession,%20org.apache.mina.core.buffer.IoBuffer,%20org.apache.mina.filter.codec.ProtocolDecoderOutput)

Maarten
  


Thanks for the clarification, Maarten, my bad : we don't extend the 
CumulativeProtocolDecoder in Directory, thus my confusion. We *have* to 
loop on a buffer just because of that.


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Re: Question about mina - deadlock?

[Emmanuel Lecharny]

Brian Parkinson wrote:
Emmanuel writes: 


---x8 snip

  

2. I've noticed one recurring error in my log files - in my HttpRequestDecoder (extends 
MessageDecoderAdapter), I am throwing an exception trying to parse up the headers - the code ends 
up getting partial line headers (for example, the decoder attempts to parse a line 
Content-Ty with nothing else on the line) - it seems like the HTTP packet is not 
complete - should I be concerned about this? An exception is thrown, and the caller will re-send 
anyways, but the error is seen a fair bit throughout the logs, and I'm wondering if this might be 
contributing to the lock up issue (?).

   
You have no guarantee that the messages sent by a client will be received fully. They can even been sent one byte at a time. It's up to you to gather all the incoming bytes until you have enough bytes to decode your protocol. In your case, however, you can use the TextLineDecoder which waits for a line feed to forward the decoded message to your handler.


---x8 snip

I am using a custom HttpRequestDecoder (which subclasses MessageDecoderAdaptor). The 'decodable' method looks correct, but then when 'decode' gets called, the buffer is incomplete - I can't figure that out. Almost invariably, the 'decode' method fails on an incomplete header line - I see a truncated header 'Content-Ty' repeatedly in the logs. 
  

Can you post your decodable() and doDecode() methods ?

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Re: ByteBuffer problem

[Emmanuel Lecharny]

On Fri, Jun 26, 2009 at 10:51 AM, Anand Boraanand.b...@aricent.com wrote:
 Hi all,

 I'm facing a weird issue. I'm trying to find out the current length of the 
 ByteBuffer which is filled with data.
 I tried to use the position() function but the problem is it increments the 
 position also.
 What is the exact function which can give me the filled up length, if any?

1) I guess that you submitted this message 3 times by mistake...
Thanks to be careful : it's not because it does not appears in the
list that it has not been received. You probably use a mail system
which adds a stupid DISCLAIMER which requires us to moderate it by
hand, otherwise the mail might be considered as Spam.

2) *always* mention the software version you are using. ByteBuffer can
be either the java ByteBuffer or the MINA 1.1.x ByteBuffer. Here, I
assume you are using MINA 1.1.x.

3) When you write ...the problem is it increments the position also
what *exactly* do you mean ?

ByteBuffer.position() gives you the *current* position on the buffer.
It does not gives you the number of elements present on the buffer.
It's all explained in the Javadoc, btw, so a bit of reading could help
at this point...


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Re: NEWBIE : Writing Protocol Codecs

[Emmanuel Lecharny]

Linz RB wrote:

Just looking for some confirmation on my thoughts (and understanding) of
writing ProtocolCodecs
Before I start - congratulations to the MINA team - MINA 2,0 is great and
the separation of repsonsibilities is a joy to work with.

I am primarily concerned with the construction of decoder codecs (as
converting a POJO to an IO Buffer is straight forward).

I have three protocols that I am looking at - and planning to convert to
using MINA. These are DHCP, TFTP, and a bespoke protocol.

So DHCP:
I took a look at the codec provided for Apache DS - but was not confident
that it would work. The decoder codec seems to assume that an entire DHCP
message would be present in the IOBuffer. But from what I have read - you
cannot make this assumption.

Have I understoodd this correctly ?
  


I suspect you are right. I have not checked the ApacheDS DHCP codec 
though, so I trust you on that.

So I have implemented a version that uses an internal state machine (not the
mina-statemachine - learning one thing at a time!) that process as much of
the received DHCP message as possible in stages : for example - process the
'static' part (first 236 bytes), then the magic cookie and lastly options
(variable length).
  

Sounds the way to go.

So TFTP:
Again - I have read the 'static' portion of the message header - and then
process the rest of the message.
The rest of the message is 0 byte terminated - so I have to look at the
IOBuffer - at the limit() position for a 0 - which indicates that the entire
message is available and can be processed (since TFTP is a strict handshake
style protocol I do no have to worry about a second message in the buffer -
I think !!)
  

Sounds ok too


How am I doing so far ? Is my approach incorrect - and not what MINA gurus
would recommend.
  
Well, that's the way I would have handled those protocol. May be someone 
else has a better idea ?

I am getting the feeling that it would be helpful to find a way to describe
a protocol and then provide a codec framework that is a close fit - is this
intention of MINA ? - so, codecs for synchronous (handshake) based protocols
(where you can only every expect a single message per IOBuffer)  v
asynchronous (streaming-like) protocols (where you may find more than one
message per IOBUffer).
  
There are a few interesting approaches so far to solve this problem, and 
some peeps have developped some Codec generators. One of them is based 
on Google Protocol Buffer (thomasz blachowicz).
I have also thought that we should have an ASN.1 compiler generating 
code for any kind of codec, but it's a very long task ...
Last, not least, we discussed a bit about creating a codec library, 
containing the most well known protocols (as we already have a few of 
them, it should not be a problem)


So this is still an open area, where those who want to play can join us !

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Re: Fwd: Need Code support

[Emmanuel Lecharny]

Kumar Phani wrote:

I want to know how to configure the ThreadPool Executor in Acceptor,exactly
what I need is acceptor needs to take 'n' requests simultaneoulsy.
  
Ok, so when you define your acceptor, you can provide a number of 
IoProcessor to use, depending on the number of processor you have. The 
Executor is a bit different beast : it's used if you have a long 
processing part somewhere in your chain, and want to decople this part 
from the processing of faster request. Not sure that you need it, it all 
depends on your application.


Basically, the number of IoProcessor defaults to Nb CPU * 2 + 1. You can 
change that by using the NioSocketAcceptor( int nbProcessor ) if you 
want to have more processor in the pool.


You have to know that a processor is associated with a Selector, so once 
a session has been registred within a IoProcessor, eveery message 
received or sent on this session will be processed by this IoProcessor. 
If you have some lengthly operation affecting one special message, then 
this IoProcessor will wait until this processing is done before 
processing the next incoming or outgoing event. However, all the other 
sessions associated with another IoProcessor will be processed in parallel.


Last, not least, if you want an IoProcessor not to be stuck while 
processing a request, just add an executor in the chain, so a pool of 
thread will be used to process the messages, instead of the IoProcessor 
thread.


In any case, before using an Executor, I would engage you to make your 
server working with the default configuration, because it's most likely 
be enough for your need. Once you have reach a point where your needs 
aren't met with the default config, then either increase the number of 
IoProcessor, or add an executor to the chain :


filterChainBuilder.addLast(threadPool, *new* ExecutorFilter 
http://mina.apache.org/report/trunk/xref/org/apache/mina/filter/executor/ExecutorFilter.html(Executors.newCachedThreadPool()));
 // Here, we use an ubound thread pool.

Hope it helps.






On Tue, Jun 30, 2009 at 2:58 PM, Emmanuel Lecharny elecha...@apache.orgwrote:

  

Kumar Phani wrote:



Hi ,

Now I am using the Apache Mina Framework.But I want to enhance the Code to
handle multiple requests by the Server(which is implemented in MINA for
communication).Its very urgent so quick response is appreciable.


  

Hey, you can post as many time as you want, but you won't get any help with
such a vague question...




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Re: questions about AsyncWeb Client sub project

[Emmanuel Lecharny]

Hi,

On Wed, Jul 8, 2009 at 9:18 PM, Sitao Yangsitao.y...@gmail.com wrote:
 Hi,

 I'm interested in trying out AsyncWeb Client in my project. I have several
 questions:

 1. where can I find either latest and stable source code or binary package
 for this project?

The source is only available through SVN. Have a look at
http://mina.apache.org/sources.html, there is some direction about how
to check out syncWeb code.

 2. where can I find javadoc for this project? I searched in apache site but
 didn't find any.

You will have to generate them :/ But you'd better check the code directly !

 Any help would be appreciated.

Hope it helps ...



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Re: How I use more than one codec filter with one acceptor

[Emmanuel Lecharny]

You can't use two codec filters in the chain, due to the way the data
are passed from one filter to another one (we use IoBuffer for that).

This will be modified in 3.0, but don't expect this version to be out soon.

In the mean time, the only option is to wrap the textline codec into
the JSON codec. Not that easy, but not that complex too.

On Thu, Jul 16, 2009 at 7:04 PM, elf.chengelf.ch...@browan.com wrote:

        I'am using a JSON based Protcol in my server program based on
 mina.To
 deal with json string,I write  codecs to decode from string or
 encode to string.I used this codecfactory like the following:
         acceptor.getFilterChain().addLast(logger, new
 LoggingFilter());
      acceptor.getFilterChain().addLast(codec_txt, new
 ProtocolCodecFilter(new
 TextLineCodecFactory(Charset.forName(UTF-8;
       acceptor.getFilterChain().addLast(codec_json, new
 ProtocolCodecFilter(new JsonCodecFactory()));

        but the filter codec_json dose not work! who can tell me why?

 elf.cheng





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Re: How I use more than one codec filter with one acceptor

[Emmanuel Lecharny]

Sorry, Ashish, after having refreshed my memory by looking at the
code, just discard what I have said.

MessageReceived() get an Object as a parameter, not a IoBuffer. So as
soon as you *know* what type the message type is, it should be plain
ok.

Sorry for the confusion.

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Re: How I use more than one codec filter with one acceptor

[Emmanuel Lecharny]

On Thu, Jul 16, 2009 at 11:24 AM, Emmanuel Lecharnyelecha...@apache.org wrote:
 You can't use two codec filters in the chain, due to the way the data
 are passed from one filter to another one (we use IoBuffer for that).

This is plain BS, now that I had time to check on the code.

MessageReceived() method manipulates an Object, not an IoBuffer.

Sorry for the confusion.

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Re: Question about SslFilter FileRegion

[Emmanuel Lecharny]

Adam Brown wrote:

While adding SSL support to our project using SslFilter, I ran into
the problem where SslFilter does not handle writes of FileRegions.
SslFilter.filterWrite() casts the message in the WriteRequest to an
IoBuffer.  However, this doesn't work for FileRegions (leading to a
ClassCastException).

Has anyone else run afoul of this issue?  Apart from sticking another
IoFilter in the chain before the SslFilter to convert the FileRegion
into an equivalent IoBuffer, is there another/better solution?
  
Well, as the SSLFilter is the first one in the chain, it has to send 
byte[] to the client. Not sure that it implies it should receive an 
IoBuffer, as in your case it would have made sense that it was able to 
accept FileRegion...


Sadly, it's currently a limitation. You have to add a converter, or you 
can extend the current SSLFilter to handle a FileRegion instead of a 
IoBuffer.


I guess you will just have to overload the filterWrite() method, calling 
its super.filterWite() when the conversion is done. A bit of a hack, but ...


Hope it helps.


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Re: mina client side question

[Emmanuel Lecharny]

刘尚�� wrote:
 哈哈.原来有chinese 在上面
   

can you please full english when posting to this mailing list?

Thanks !


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ApacheCON US 2009 Travel Assistance

[Emmanuel Lecharny]

The Travel Assistance Committee is taking in applications for those wanting
to attend ApacheCon US 2009 (Oakland) which takes place between the 2nd and
6th November 2009.

The Travel Assistance Committee is looking for people who would like to be
able to attend ApacheCon US 2009 who may need some financial support in
order to get there. There are limited places available, and all applications
will be scored on their individual merit. Applications are open to all open
source developers who feel that their attendance would benefit themselves,
their project(s), the ASF and open source in general.

Financial assistance is available for flights, accommodation, subsistence
and Conference fees either in full or in part, depending on circumstances.
It is intended that all our ApacheCon events are covered, so it may be
prudent for those in Europe and/or Asia to wait until an event closer to
them comes up - you are all welcome to apply for ApacheCon US of course, but
there should be compelling reasons for you to attend an event further away
that your home location for your application to be considered above those
closer to the event location.

More information can be found on the main Apache website at
http://www.apache.org/travel/index.html - where you will also find a link to
the online application and details for submitting.

Applications for applying for travel assistance will open on 27th July 2009
and close of the 17th August 2009.

Good luck to all those that will apply.

Regards,

The Travel Assistance Committee

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Re: Message processing issue with MINA

[Emmanuel Lecharny]

Bruno,

I want to give you some result we get on Apache Directory Server, which 
is based on MINA.


Currenly on my laptop, a 2Ghz centrino, I'm able to process around 4000 
search requests per second. That mean a request is handled in *less than 
a 1/4 millisecond*. And trust me on that, the processing is quite complex.


Whatever you do with currentMillis on the message level is irrelevant. 
Measuring the execution time for a single message will at best gives you 
a consistent duration only when the message is stuck for more than a few 
tens of ms. Otherwise, you will get a random value between 0 and 20 ms, 
depending on your platform.


There is of course no guarantee that every message will be processed in 
less than 200 ms, this is Java... It's just that statistically, it will 
be the case for 99,999% of the messages.


So the best you can do to measure the time it takes to process a single 
message is to do what you are doing, but only gather times when a 
message is processed in more than, say, 50 ms. Otherwise, simply 
consider that the message has been processed 'fast enough'.


When you'll get the number of messages processed in more than 50 ms, you 
will also see if this is acceptable from your PoV.


last thing, as Joshua  Bloch says in his book Effective Java :

...Finally, note that System.nanoTime is used to time the activity 
rather than System.currentTimeMillis. For interval timing, always use 
System.nanoTime in preference to System.currentTime-Millis. 
System.nanoTime is both more accurate and more precise, and it is not 
affected by adjustments to the system’s real-time clock (Item 69, 
page 276)



Bruno de Carvalho wrote:

Meanwhile, I've updated the code and implemented another flag,
SEQUENTIAL. With this flag, packet N+1 will only be sent to the server
after packet N has been received. With this flag enabled you will
better grasp  what I'm experiencing - sequential mode has equal global
and per-packet averages, while on non-sequential mode this doesn't
happen.

The update file is at http://bruno.factor45.org/LifetimeIssues.java

I'll try to dig into MINA's code and see what I can come up with.


Best regards,
  Bruno

On Fri, Jul 24, 2009 at 3:18 PM, Christopher
Poppchristopherp...@yahoo.com wrote:
  

Hello,



Speaking in numbers, executing the test multiple times, I get a constant
global average of ~1ms lifetime, but individual lifetime measurement
averages ranges 40~80ms.



I downloaded your code and gave it a run...it printed out the following with 
the defaults (no sleep).

   [SERVER] Binding Server to localhost/127.0.0.1:20002 TCP
   [SERVER] Bound to localhost/127.0.0.1:20002
   [SERVER] Session created: /127.0.0.1:2598
   [CLIENT] Session created: localhost/127.0.0.1:20002
   [CLIENT] Session opened: localhost/127.0.0.1:20002
   [CLIENT] Connected to server, sending message.
   [SERVER] Session opened: /127.0.0.1:2598
   [SERVER] Test completed, took 63ms to receive 100 packets (63ms after 
sleep discounts).
   [SERVER] Calculated average lifetime was 00.63ms.
   [SERVER] Individual average lifetime was 3.03ms.
   [CLIENT] Session closed: localhost/127.0.0.1:20002
   [SERVER] Session closed: /127.0.0.1:2598
   [SERVER] Received a total of 5300b

Maybe I am missing something, but it seems pretty reasonable to me.  I ran it 
under Windows XP on a laptop with a dual core processor.

Chris






  



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Re: reconnect the server?

[Emmanuel Lecharny]

阳建军 wrote:
 Hi, I wirte a Long connection client， it's sample code as：
  public void startClient() throws Exception {
   NioSocketConnector socketConnector = new NioSocketConnector();
   socketConnector.setHandler(...);
   .
   ConnectFuture future = socketConnector.connect(new InetSocketAddress(ip ,
 port));
   future.awaitUninterruptibly();
  }

  I implement IoHandler interface,  in sessionClosed method, I try to
 reconnect the server side,  it works, but still print reconnect
  characters,
   
Looking at your code, this is expected... It's not because the session
as been connected that the sessionClosed() method will not execute the
rest of its code...

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Re: problem with FileRegionWriteFilter

[Emmanuel Lecharny]

Adam Brown wrote:

i'm currently using a FileRegionWriteFilter 'before' an SslFilter to
breakup FileRegion objects into chunks that SslFilter can handle
(since SslFilter doesn't handle them directly).  however, this filter
chain also has IoBuffers written to the same IoSession.

the problem i'm seeing appears to be that the IoBuffer is not being
sent by MINA (with messageSent() being sent back up the chain and
IoHandler) before the first IoBuffer generated by the
FileRegionWriteFilter is written.  because of this ordering, my
IoBuffer (not the ones created by FileRegionWriteFilter) is lost to
the chain and never has messageSent() called on it.  in addition to
the messageSent() call made with the FileRegion, some of the IoBuffers
generated by FileRegionWriteFilter escape and have messageSent()
called on them, passing them up the filter chain (and ultimately to my
IoHandler).

so really, i've got two problems :-).
  


Are you using an ExecutorFilter? If so, which kind of threadPool are you 
using ?


Can you push a very simple piece of code demonstrating the problem so 
that we can debu it and understand what's going on ?


Thanks !

PS: MINA version, etc... That helps !

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Re: Understanding DemuxingProtocolCodec

[Emmanuel Lecharny]

Daryl Ayres wrote:

boB,

Based on what you've said, it sounds like I would need to have a  
ThrowawayDecoder as the last decoder in my ProtocolCodecFactory to consume or clear 
those packets in the protocol I'm not currently handling. I'll create one and give it a 
go.
  
This would be the approach I would implement. Basically, decoding all 
the messages, and throwing away those I don't want to pass to the handler.


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Re: how implement MulticastSocket Server over Mina ?

[Emmanuel Lecharny]

Survivant 00 wrote:

Anybody can give me a hint ?
  
It's something we have in the pipe for MINA 3.0, but it's not available 
in MINA 2.0 atm.


I have 3 cases that I want to replace by MINA.

#1 - Send a UDP message using MulticastSocket and close the socket.
#2 - Send a UDP message using DatagramSocket but wait for a response (wait
until TTL)
#3 - Listen for UDP message using MulticastSocket (while(true))
  

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Re: Decoding embedded packets

[Emmanuel Lecharny]

boB Gage wrote:
I'm running into an issue decoding both packets from a device that 
embeds commands inside it's responses.


Everything is flagged with start/stop bytes and can be parsed without 
problems.  
The problem is, at the point in the code that I'm parsing this, I'm in 
the guts of a specific packet-type Decoder object.   This particular 
object cannot decode the embedded packet (it's a different type) so I 
need to push the embedded packet data back into Mina's framework in 
such a way that it's treated as new incoming data and runs through the 
standard decodable() sequences to find the right decoder object.


It would be a bit overkilling ...

If I understand correctly, you get a message like :

startopaque dataend

with opaqueObject = some decodable data, using another decoder


We have that in ADS, and we handle this differently. Basically, this is 
a two level decoder, encapsulated in the protocolDecoder we have 
implemented.


If you consider that the decoder is *not* a part of MINA (it's just 
called through a callback by MINA), you can do whatever you want once 
you have read your opaque data, including calling another decoder from 
your decoder.


That would probably be the easier way to deal with such messages.

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Re: Why there is no explicit SessionEvent class in MINA?

[Emmanuel Lecharny]

Christian Migowski wrote:

On Mon, Aug 24, 2009 at 8:23 AM, Emmanuel Lecharnyelecha...@apache.org wrote:
  

Christian Migowski wrote:


(and
more actively developed).
  

FUD.



you are easily scared, hm? ;)
  
Look, I'm very happy that Trustin has found a place he can have fun in. 
What he has done in the past, and what he is doing now is just a proof 
he is a talented coder. So I'm very happy that Netty 3 is successful, 
and so with Grizzly. Everyone has its own little place in this ecosystem.


Now, I don't see any value added in spreading FUD. This is just childish.

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Re: StateMachine deadlock on StateContext synchronization

[Emmanuel Lecharny]

Rafael Marins wrote:

Hi folks,

Hi !


I've found a deadlock at StateMachine#handle(StateMachine.java:129) 
and 
StateMachineProxyBuilder$MethodInvocationHandler.invoke(StateMachineProxyBuilder.java:253), 
when using two layered state machines in pipeline. It get into 
deadlock because both methods seems to be called concurrently.


Can you fill a JIRA with the thread dump attached so that we don't 
forget about this issue ?

Many thanks !

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Re: Examples of IoEventQueueThrottle use?

[Emmanuel Lecharny]

Daniel John Debrunner wrote:


I'm seeing hangs when I use an IoEventQueueThrottle as below. I read 
the comments in the javadoc about requiring an executor in the filter 
chain.  I get no hangs if I do not add writeThrottle into the chain 
(my app is  currently throttling by waiting for every 100th write to 
complete).


// Setup
NioSocketConnector connector = new NioSocketConnector();
   
connector.getFilterChain().addFirst(executor, new ExecutorFilter(1));

connector.getFilterChain().addLast(writeThrottle,
new WriteRequestFilter(new IoEventQueueThrottle(10)));


// message sennding

IoBuffer buf = prepareBuffer();

WriteFuture wf = session.write(buf);

Are there any examples of how to use IoEventQueueThrottle for write 
throttling?


The problem is that you probably have a slow client. Even if you use a 
throttling mechanism, you will block one thread until all the write is done.


By using an executor, the writes are put into a queue, and the thread is 
freed, and able to accept another client interaction.


Now, if you have many slow clients, at some point, the executor will 
become a bottleneck. Also you can quickly saturate the memory if you are 
writing huge messages to slow clients, as they will remain in the queue 
for a long time.


A way to manage this is to split the message in small chunks (say, 1kb), 
and wait until the selector is ready for the next submission. Alas, you 
don't have a hand on the selector, but you can manage the MessageSent 
event. So if your application, you split your message in small parts, 
manage the MessageSent event, deal with the overhead, add an executor, 
you can handle any kind of scenario, including a DOS by slow reader (you 
will just have to set a timeout or manage idleconnection)


That would be good for sure to have such a mechanism implemented in 
MINA... This is not exactly what does the IoEventQueueThrottler : it 
does limit the size of data sent to the client to a certain size, 
limiting the throughput. Probably not what you want.


Hope it helps


Thanks,
Dan.




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Re: Examples of IoEventQueueThrottle use?

[Emmanuel Lecharny]

Daniel John Debrunner wrote:

Emmanuel Lecharny wrote:

Daniel John Debrunner wrote:


I'm seeing hangs when I use an IoEventQueueThrottle as below. I read 
the comments in the javadoc about requiring an executor in the 
filter chain.  I get no hangs if I do not add writeThrottle into 
the chain (my app is  currently throttling by waiting for every 
100th write to complete).


// Setup
NioSocketConnector connector = new NioSocketConnector();
   connector.getFilterChain().addFirst(executor, new 
ExecutorFilter(1));

connector.getFilterChain().addLast(writeThrottle,
new WriteRequestFilter(new IoEventQueueThrottle(10)));


// message sennding

IoBuffer buf = prepareBuffer();

WriteFuture wf = session.write(buf);

Are there any examples of how to use IoEventQueueThrottle for write 
throttling?


The problem is that you probably have a slow client. Even if you use 
a throttling mechanism, you will block one thread until all the write 
is done.


I don't think so. Without the writeThrottle in the filter chain I 
see 8000-2/sec messages sent from the above code to a mina server 
(2.0 M6).

Hmmm. So wrong assumption from my side : you don't have a slow client.
Adding the writeThrottle leads to a hang, no messages seen by the 
client.



That would be good for sure to have such a mechanism implemented in 
MINA... This is not exactly what does the IoEventQueueThrottler : it 
does limit the size of data sent to the client to a certain size, 
limiting the throughput. Probably not what you want.


So the threshold parameter to IoEventQueueThrottler constructor is 
number of bytes, not number of messages?

Number of bytes. Here is the portion of code which does that :

   public void offered(Object source, IoEvent event) {
   int eventSize = estimateSize(event);
   int currentCounter = counter.addAndGet(eventSize);
   logState();

   if (currentCounter = threshold) {
   block();
   }
   }

FYI, the counter is *never* decreased.

To be frank, this is not a piece of code I know, but from what I see, 
it's *extremly* dubious that id does something useful, and most likely 
to block forever.


I would suggest not to use this, and to fill a JIRA reporting the problem.

Sorry for that...

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Re: help !! Socket operation on nonsocket

[Emmanuel Lecharny]

rzo wrote:

Hello,

Looking further into this issue, I found out that the server has 2 
network cards with teaming - load balancing - turned on.


Could this lead be the cause ? Is this a windows, java or windows issue ?


MINA version ? JVM version ? OS ? Code ?

Thanks ...

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Re: backend permanent connection

[Emmanuel Lecharny]

Aleksandar Lazic wrote:

The easiest way to do that is to have a class in your application that
extends the IoHandler interface : it will handle the messageReceived
event.


I have a used the IoHandlerAdapter isn't it enough?

It's ok, as this Adapter implements IoHandler.

I use the IoHandler, I yust want to reuse the connection which I have
created at server startup time.
Which connection ? The connection to your backend (whatever it is, but 
let's assume it's a JDBC connection, even if it's not) ?


If so, as soon as the messageReceived() method can have access to this 
connection, then you are all set.


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Re: IoSession.getCreationTime() in milliseconds instead of nanoseconds

[Emmanuel Lecharny]

Adam Brown wrote:

Unless I'm missing something, despite what the Javadoc for 2.0-M6
says, AbstractIoSession.getCreationTime() returns the creation time in
milliseconds, not nanoseconds.  Is the plan to switch from millis to
nanos, or is the Javadoc wrong?

-adam

  

The javadoc was incorrect. It is fixed now, thanks to your report.

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Re: IoSession.getCreationTime() in milliseconds instead of nanoseconds

[Emmanuel Lecharny]

Adam Brown wrote:

Unless I'm missing something, despite what the Javadoc for 2.0-M6
says, AbstractIoSession.getCreationTime() returns the creation time in
milliseconds, not nanoseconds.  Is the plan to switch from millis to
nanos, or is the Javadoc wrong?

-adam

  

Th eJavadoc is wrong. It's fixed now.

We can't provide nanoseconds in Java, at least it's not reliable.

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Re: help !! Socket operation on nonsocket

[Emmanuel Lecharny]

rzo wrote:

oops sorry, and sorry for the delayed answer.


I am using mina-2.0.0-M4

Switch to 2.0.0-M6.

The message you get is probably due to the fact that the client has 
closed the socket before it has been accepted. Not exactly an error.


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Re: Newbie

[Emmanuel Lecharny]

Chenna Venkatasubbaiah-KRG637 wrote:

 Hello All - Recently while browsing I came to know about MINA. I am a
Java/J2EE developer.

I am working in wireless broad band and networking company and I have
limited knowledge on networking domain. 


In our company we manufacture Wireles switches, Routers and Access Ports
etc., And its softwares.

I would like to know How MINA will be useful and what kind of business
applications we can build using MINA. 
  
I have no idea. Do you have something more precise in mind ? Your 
question is pretty vague at this point. A bit like I have discovered 
Java, and I want to know what kind of business applications I can build 
using this language...


In any case, reading http://mina.apache.org/testimonials.html could give 
you a clue about what people are using MINA for.


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Re: Mina concurrency issue in servicemix camel routing

[Emmanuel Lecharny]

Hi,

you should really see MINA as a framework on top of NIA, ie what yu do
with a single socket, you have to do the same with a MINA connection.
The big difference is that a MINA session is associated with some
context, but otherwise, it behaves the same.

The message you got just indicates that the underlying socket has been
closed by the server. You have to deal with this, either by
re-openning the connection, or by understanding why the server has
closed the connection (I don't now if the protocol close a connection
for some reason like a bad message has been sent, but if this is the
case, you have to check your codec).

One thing is sure is that once the session has been terminated, you
have to create a new one.

At some point, analysing the bytes sent on the wire could help
(wireshark to the rescue !) to check that you are sending a correct
message.


Btw, please when you post a message, tell us which MINA version you
are using, with the java and OS version. It can help !

On Mon, Sep 14, 2009 at 8:40 AM, Alex, Hitha
hitha.a...@sabre-holdings.com wrote:
 I am getting errors when trying to send more than one message to a
 legacy tcp/ip service using a Apache camel mina endpoint in camel 1.6.
 Everything works as  expected when requests are send one at a time I am
 not sure, if the issue is due to remote host forcibly closing
 connection. My simple java socket client works fine by sending multiple
 concurrent transactions to the same legacy server. I have a feeling it
 is something in my mina configuration or codec setting. Does mina reuse
 connections for multiple messages? The legacy system is expecting
 separate connections per request.
 I am using an extension of CumulativeProtocolDecoder. Do I need to do
 something in dispose() method to forcibly close the connection or
 session?



 Any clues will be appreciated.



 Following is the error I am getting.

 Caused by: java.io.IOException: An existing connection was forcibly
 closed
  by the remote host
        at sun.nio.ch.SocketDispatcher.read0(Native Method)
       at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:25)
       at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233)
        at sun.nio.ch.IOUtil.read(IOUtil.java:200)
        at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236)

        at

 org.apache.mina.transport.socket.nio.SocketIoProcessor.read(SocketIoProc
 essor.java:218)
       at

 org.apache.mina.transport.socket.nio.SocketIoProcessor.process(SocketIoP
 rocessor.java:198)





 Thanks,



 Hitha

 682-605-1897











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Re: Question on Message writing

[Emmanuel Lecharny]

In any case, I would gather all the elements inorder to send only one
message instead of many. It's more efficient.

On Mon, Sep 14, 2009 at 7:28 AM, Christopher Popp
christopherp...@yahoo.com wrote:



 2)Does Mina keeps the order of the messages sending when replies are
 dispatched? In another words: if I do multiple IoSession.write(), do I
 receive the messageSent() in the same order I do the write ?

I am really not sure on this, but I think it will, unless you have a
Executor down in the Chain.

Anyone?


 For each session, the order of messages being received should be the same as 
 they are sent.  The default behavior of the ExecutorFilter is to provide an 
 OrderedThreadPoolExecutor, which will continue to maintain the order of 
 events per session.  Setting up the ExecutorFilter with an 
 UnorderedThreadPoolExecutor would result in things possibly getting out of 
 order.

 Chris Popp






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Re: MINA User Guide - Chapter 2 ready for review

[Emmanuel Lecharny]

Ashish wrote:

Folks,

MINA User guide Chapter 2 - Basics is ready for review. Here is the
link (http://cwiki.apache.org/confluence/display/MINA/Chapter+2+-+Basics)

P.S. - I missed announcing chapter 1 updates in User ML

I updated it in a little hurry, as I wanted to finish it before weekend.

Would be great, if you can provide feedback, on the ways to improve it.

Alternatively, would be great if you can drop your wishlist for documentation.

What should be the next topic in User Guide - Filter's/Connectors?

Any suggestions?

  
Hi Ashish, I have added a comment on the first wiki page. I will review 
the other one asap.


Thanks for the great job !

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Re: Performance Boosting: Multiple Sessions or Multiple Ports or ... Both?

[Emmanuel Lecharny]

Sebastian Wagner wrote:

I read in the docs that: 1 session == 1 Thread
  

1 *active* session ... ! You may have thousands of inactive sessions.

So opening several Session in the Client should have an impact on the
Performance.
  

No, not unless you have many active sessions.


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Re: SSLFilter before ExecutorFileter?

[Emmanuel Lecharny]

Adi wrote:

Hi all,

Openfire ( a open source xmpp server) uses mina. They seem to be using
version 1.1.8 of mina.

In the code i did see this, comment.

/ /TODO Temporary workaround (placing SSLFilter before ExecutorFilter) to
avoid deadlock. Waiting for
// MINA devs feedback

ioSession.getFilterChain().addBefore(org.apache.mina.common.ExecutorThreadModel,
tls, filter);

Can setting up the ssl filter before ExecutorThreadModel filter
cause any problems? Or is it ok to leave this as is. Any insight is
appreciated.
  
The SSL filter has to be put at first position in the chain, as the 
handshake has to occur first.


In fact, for MINA 3.0, we most certainly would remove the SSL layer from 
the filter chain, as it's
not exactly a part of the data processing, but much more a negociation 
about the transport to use (should it be secure or not).


Right now, for MINA 1.x and MINA 2.0, be sure to put it on the first 
place in the chain.


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Re: Null Character in Received Message/String

[Emmanuel Lecharny]

Sica, David (David) wrote:

I have a process that is sending an ASCII string that contains a Null
Character in the middle of the string.  It seems that my MINA server is
only receiving the string before the Null Character and then ignoring
everything after.  Does this seem consistent with how MINA should be
handling it and if so how do I change it to be able to receive the
entire string including text after the null character?
  
You should check your decoder. MINA does not care about \0 bytes, they 
are just plain normal bytes to it.


PS : Please when you post on this list, provide the MINA version you are 
using.


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Re: Understanding MINA 1.1.7. configuration

[Emmanuel Lecharny]

Hi,

Darryl Pentz wrote:

I'm trying to get my head around the way that MINA 1.1.7. configuration is 
meant to work.
  
First, I think that you should switch to MINA 2.0.0-M6. The Thread model 
is much easier. Also consider that this version is mainained, and 
performances are better. That being said ...
The current implementation I'm using is basically the default implementation. No arg SocketAcceptor() constructor, with no ExecutorFilter in the filter chain. This leads to the AnonymousIoService thread pool that I observe in the thread dumps. 


However if I look at this: http://mina.apache.org/configuring-thread-model.html 
it appears I am not using the correct strategy, and the suggestion is to 
disable the default threading model and instead specify separate Executor 
thread pools. If I understand it correctly, there appears to be 1 IoAcceptor 
thread, N IoProcessor threads (N being the number you specify, suggested to be 
#CPU's + 1) and then an executor threadpool to do the 'work'.

What I'm struggling to understand is why the IoAcceptor requires a threadpool 
in addition to the ExecutorFilter threadpool. What is the IoAcceptor threadpool 
used for? If there's only 1 IoAcceptor threads, and (in my case) 3 IoProcessor 
threads, then what is the threadpool used for? Furthermore, what is the 
consequence of this approach using an ExecutorFilter over the current default 
approach I'm using.
  


As we associate a session with an IoProcessor, when a message is 
processed by this IoProcessor, no other session can be processed by this 
IoProcessor. If the handler takes a while to process the event, then it 
will block potentially many other messages. Having an exectutor in the 
chain, you will allow more than one message to be processed by a single 
IoProcessor (what happens is that the message is dispateched to the 
Executor, and enqueued. This queue is handled by the ThreadPoolExecutor, 
but at the same time, the IoProcessor is able to process more messages).


The executorFilter needs to know about the ThreadPool model you will 
use, and this is the information you provide. If you don't tell what 
kind of ThreadPool model to use, it will use an UnorderedThreadPool by 
default. There is no threadPool in the IoAcceptor btw.


Hope it helps...

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Re: Socket sendBufferSize and receiveBufferSize

[Emmanuel Lecharny]

Ronen wrote:

Thanks.
By disabling naggle algorithm you mean setting the TCP_NODELAY?
  

yep.


On Wed, Sep 30, 2009 at 12:05 PM, Emmanuel Lecharny elecha...@apache.orgwrote:

  

Ronen wrote:



Hi,
I'm trying to figure out what is the guideline for setting the values of
sendBufferSize and receiveBuffersize on sockets.
Is making them large as possible always the best practice?
How does buffer size effect performance in general and in cases where
clients have low bandwidth?
Is there any benchmark somewhere?


  

There is no simple response. It all depends on the size of you data. If
they are small, the best is probably to have 1kb buffersize, as in any case,
the size of your TCP (assuming you are using TCP) packets will be bounded to
a bit less than 1500 bytes  (depending on the MTU size).

If you are using large messages, then you might want to use larger buffers.

The idea is to limit the number of processing in the chain (with small
buffers used fo long message, you will walk the chain once per buffer,
probably not a good idea)

Remember to disabled the naggle algorithm for small messages too, otherwise
you might have horrible performance.



Thanks,
Ronen



  

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Re: Push message from server to client with mina

[Emmanuel Lecharny]

A naive approach would be to do something like :

while (true) {
 session.write ( your data to the client );
 Thread.sleep( 1000L );
}

it does the trick *IF* you don't have a lot of clients (and you'll have 
to add an Executor filter in the chain, otherwise you wo'nt be able to 
deal with more than the number of threads you have defined in the acceptor).


However, this is not the best solution. The problem is that in order to 
process a request, a thread is selected, and released when you quit the 
handler (ie, once the message has been processed on the server side).


A better solution would be, as suggested by mark, to have a separate 
thread having a list of all your client's IoSession. When the clock 
tiks, you get all the active sessions and you simply write a message 
into them :


while ( true ) {
 for ( IoSession session : MySessions ) {
   if ( session.isConnected()  ! session.isWriteSuspended()) {
 session.write( time to wake up ! );
   } else {
 // some cleanup here, as the session has been closed.
   }
 }

Thread.sleep( 1000L );
}

Hope it helps too.

Mark Wallsgrove wrote:

Hey.. I haven't been using Mina for long, but what you could do is
create a new object that runs on a thread that uses the filter chain
to fire a event every x seconds. Your handler should then do the rest.
Once the event has been fired the thread should then go back to sleep.
I guess you could use the connection object to gather the sessions /
filter chains? Hope this helps..

Best regards,
Mark Wallsgrove

On 10/3/09, CoolHedin coolhe...@yandex.ru wrote:
  

Hi. I develop an application using your excellent library. But I had a
difficulty.
I need to send messages from server to clients, by timer.
and I do not understand how to do it.
for example, i send every 1 minutes 'Hi everyone' message to all conection
--
Sincerely yours,
Sergey Paramonov
Adept Team, www.adept-project.com





  



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Re: Creating an SSL Client

[Emmanuel Lecharny]

Mark Wallsgrove wrote:

Hey guys,

I need to create a client which can read data of an HTTPS connection
.. I have seen examples for SSL servers, but not clients. Could
someone provide me with a really basic example? Surely it isn't too
hard?

  

Have a look at the chat client.
http://mina.apache.org/report/trunk/xref/org/apache/mina/example/chat/Main.html


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Re: Which version of MINA to use?

[Emmanuel Lecharny]

I looked at the Apache cons slides and it seems that MINA exactly matches 
my 
requirements. I'm a bit unsure about the version to use. Since I start now 
version 2
might be ready when I need to freeze my code. How stable is the TCP client 
and 
server part of MINA 2?
  
Version 2 is probably the one to use. We still have some bug pending, 
but not any that could block you except if you are using mina in some 
very special ways.


We should be able to cut a release in october, I think...

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Re: 1.1.7 based client creates too many threads ...

[Emmanuel Lecharny]

Hi,

instead of creating anew connector for each new connection, just connect 
using the same connector to the newly created InetSocketAddress.


Alex Shneyderman wrote:

Hi, all!

I am trying to run load simulation agent, which will have to open up
as many connections as it possibly can - I am trying to determine wht
the upper limit will be on my laptop. I connect as follows:

SocketConnectorConfig config = new SocketConnectorConfig();

config.getSessionConfig().setReuseAddress( true );

SocketConnector connector = new SocketConnector();

connector.getFilterChain().addLast( codecs, new
ProtocolCodecFilter( new CAGProtocolCodecFactory() ) );

SocketAddress address = new InetSocketAddress(
cagInfo.serverControlIp(), Integer.parseInt(
cagInfo.serverControlPort() ) );

ConnectFuture future = connector.connect( address, new
CAGIoHandler( this, csChannelEventListener ), config );

future.join();

I observe that for every connection I make MINA creates 3 threads. so,
there is clearly a problem since even if I am able to open as many
connections as I would want I am currently having problem with
threads. I thought one of the ideas behind MINA project is an
efficient handling of threads but my thread dump tells me:

795  [main] DEBUG CAGRunner  - Thread[PooledByteBufferExpirer-0; true; true]
795  [main] DEBUG CAGRunner  - Thread[SocketConnector-0; false; true]
795  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-0.0;
false; true]
795  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-1; true; true]
795  [main] DEBUG CAGRunner  - Thread[SocketConnector-1; false; true]
795  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-1.0;
false; true]
795  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-2; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-2; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-2.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-3; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-3; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-3.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-4; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-4; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-4.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-5; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-5; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-5.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-6; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-6; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-6.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-7; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-7; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-7.0;
false; true]
796  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-8; true; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnector-8; false; true]
796  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-8.0;
false; true]
797  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-9; true; true]
797  [main] DEBUG CAGRunner  - Thread[SocketConnector-9; false; true]
797  [main] DEBUG CAGRunner  - Thread[SocketConnectorIoProcessor-9.0;
false; true]
797  [main] DEBUG CAGRunner  - Thread[AnonymousIoService-10; true; true]

3 threads per connection. I tried 20 connections as well and the
thread number went to 60.

Is it possible to control the number of threads on the client side ?

Thanks,
Alex.

  



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Re: Mina and SSL

[Emmanuel Lecharny]

GERARD Vincent AWL-IT wrote:

Hi all,
Using Mina 1.1.7, I was busy testing the EchoServer example. I just wonder why 
do you extends ServerSocketFactory and SocketFactory ?? Is it necessary when 
you use SocketAcceptor or SocketConnector ? Are they called in the example (and 
where?).

Related to this, I have find the Jira 
http://issues.apache.org/jira/browse/DIRMINA-650 . What is its status ? do you 
have more information about it ?
  

Hi,

to be frank, I'm not sure we will spend some time fixing 1.1.7 if there 
is a bug in it. We are just voting 2.0.0-RC1, expecting 2.0 to be out 
pretty soon after. Then 1.0 and 1.1 branches will be considered dead wood.


It's just a question of time we can spend on the current code, and it's 
little for many of us...


Anyway, have you tried 2.0.0-M6 ? It's most certainly way more stable 
than 1.1.7, more efficient, and probably has a better doco.


Thanks !


Thanks




  

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Re: Unable to reset the writeIdeal time

[Emmanuel Lecharny]

binayakumar.pa...@wipro.com wrote:

Hi,
 
I am using Apache mina-core-2.0.0-M1. and Java 6 . I am unable to

reset the write Ideal Time.
.. The client is set by writeIdealTime(30) but when ever I received
any message from server I have to reset the writeIdealtime. Thanks in
advance for any support.
  

Uh ??? What is writeIdealtime ?

Can you please upgrade to 2.0.0-M6 at least ?

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Re: Configuring MINA 1.1.7 Acceptor - best practise

[Emmanuel Lecharny]

Darryl Pentz wrote:

Hi all,

Apologies for bumping this one - I was sure somebody would be able to respond 
to this. We're seeing some really poor performance on some of our higher load 
servers, but the problem is that to run profilers on them when they're under 
load is just not feasible. So I'd like to know whether if ~800 concurrent 
connections were pinging, would the below configuration be limited to the pool 
of 16 AnonymousIoService objects and would this result in pegging the CPU 
really high? Should I be switching to the manual threading model as per my 
second post on this thread?
  


Very difficult to say.

You have to understand that it all depends on the way you process 
messages in the codec and in the handler. MINA does not eat a lot of CPU 
itself.


The number of thread you need to setup is impossible to define without 
any knowledge about your code.


For instance, if you access a database in the handler, it's pretty 
obvious that the thread might be stuck for a few ms, and with 800 
concurrent requests running, you will get awfull performances. At this 
point, it's all about decoupling the code run in handler from the MINA 
stack, using Executors.


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Re: Configuring MINA 1.1.7 Acceptor - best practise

[Emmanuel Lecharny]

Darryl Pentz wrote:

Hi Emmanuel,

Thanks very much for your reply.


  

The number of thread you need to setup is impossible to define without any 
knowledge about your code.



  

For instance, if you access a database in the handler, it's pretty obvious that 
the thread might be stuck for a few ms, and with 800 concurrent requests 
running, you will get awfull performances.


That is exactly what happens. Virtually all calls that come in via a MINA 
connection are hitting our DB. So this being the case, do you recommend the 
approach documented here:
http://mina.apache.org/configuring-thread-model.html

  

At this point, it's all about decoupling the code run in handler from the MINA 
stack, using Executors.


Would you mind looking at my second post which shows the implementation I have 
done using the configuration in the document indicated above, and letting me 
know whether that looks correct to you? I would really appreciate that. Just so 
I know I'm on the right track with the configuration section. As I said 
earlier, we are going with 2.0 in the next release, but I need to get out a 
patch release to buy us some time.
  


AFAICT, sounds good to me.

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Re: Is it just me?

[Emmanuel Lecharny]

boB Gage wrote:
Rats, I musta screwed something up on my endI hear RC2 will 
contain the only patch we've applied, so I'm thinking we'll just skip 
RC1 if I can't make the source build anymore...


I just checked out a clean copy (  
http://svn.apache.org/repos/asf/mina/trunk ) and ran ' mvn clean 
install ' and am still getting the same odd version failure
Sometime, you also have to doom your .m2/repository directory before 
running a mvn clean install.


Can you try that ?

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Re: Processing order of filters

[Emmanuel Lecharny]

Julien Vermillard wrote:

Le Tue, 27 Oct 2009 10:44:30 +0100,
pi...@dokom.net a écrit :

  

Well, I use version 2.0M6 and I have trouble with the order of
filters. I created a protocol encoder/decoder and some filters. The
filters extend IoFilterAdapter and overwrite messageReceived/Sent.
This works well for for inbound messages, the protocol is used first
and than the filters are used on their order.
The trouble starts outbound. I would expect that the filter chain is
processed in the reverse order but id did not! The filters are called
in the same order as the for the inbound messages. Is this the
designed behaviour? Any ideas?





The messageSent is a PITA, the filterWrite is in reverse order.
  
Right, I forgot to mention that the write is done in reverse order. this 
is where it's even more confusing...


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Re: Processing order of filters

[Emmanuel Lecharny]

We have had the same issue in Apache Directory project, and we have had
to implement the codec in a certain way in order to make it work, as it
was a two stage decoder. Not really easy...


Could you please explain?
We have a two stages decoder. It's all done in one single codec, which 
is stateful. We store the current state in the IoSession, and when we 
receive more bytes, we resume the decoding exactly where it stopped.



I must admit that the current impl is also a perfect maze... Debugging
MINA is just requiring a very high IQ :/


Doesn't that make you think?

Eh... Why do you think we started a 3.0 ???



Another thing I tried is the implementation of
filterChain.getAllReverse() gives you the reverse ordered filters. But
if you ask the retrieved list with getNextFilter() on  you get the old
order. I would assume that you get the reverse order too, but you will
probably answer that it works as designed. I can't argue about this.
All of this is quite frustrating, I think I have to create my own 
filter
chain as handler. That's the only solution I see that matches my 
time frame.



Probably... Sorry for that, the current code is not perfect, and this
is the reason we are really impatient to start the 3.0 version.


And again. I can not use a handler to implement my own filter chain.
The handler (messageSent) is to late on the outbound side. What to filter
if it's already sent?
The MessageSent event is just produced when the message was actually 
*sent*. You can do a lot of thing with this information, like gathering 
stats, etc. Now, it may not have to be processed by a codec. In this 
case, you don't have to implement the method in your filters.


Overall, I suggest you have a look at the many examples we provide, to 
see how MINA works in detail. There is probably something you have 
missed, due to the documentation which is not explicit enough. I 
understand that's a bit frustrating, but there is little I can do here 
to help you with your frustration except telling you that if you feel 
you can help building a better framework, then please, join us !


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Re: please remove me from users list

[Emmanuel Lecharny]

Shiran wrote:
 



  

Please follow the instructions on http://mina.apache.org/mailing-lists.html

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Re: TCP protocol acknowledgement delay(looks like piggybacking with the message response)

[Emmanuel Lecharny]

Erinc Arikan wrote:

Thanks so much  Emmanuel;

I totally forgot to mention that I am using MINA 2.0 RC1.

I gave it a try and It worked great, I see 2-3 seconds between ack and
response now.
  

Great !

One thing that I wonder is optimum number of threads for an executor.

For now I set it to 10, But I don't think that I would need more than 2-3
threads at a time for a connection. Do you think that it would affect the
performance drastically when I have 1 devices connected to my gateway.
  

I think it does not matter too much, as soon as if your processing is
fast, then the threads will be made available fast enough for other tasks.

Now, if it takes, say, 100 ms to process a request, and if you have 100
simultaneous tasks running, then you definitively need 10 threads
available in the pool (probably a few more in order to avoid
bottlenecks). So if you have 1 devices doing one request every 5
seconds, and if it costs 100 ms to process a request, the the math is
simple : you will have an average of 200 requests being processed
simultaneously, so you'll need 200 threads. But a 100 ms processing time
is HUGE.

Note : when I say *simultaneous*, it means requests being processed *at
the same time*. (people are often confusing requests per second and
number of requests that can be processed simultaneous at a specific moment).

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Re: Problems using TextLineCodecFactory

[Emmanuel Lecharny]

Mark Wallsgrove wrote:

Hi all,
  

Hi,

Is there a new line sent at the very end off your incoming message, so 
that the textLineDecoder can know that the message has been fully received ?

I am having some problems with the TextLineCodecFactory  Mina 2.0.0.
For some reason when I try to receive some data as a client I get
this:

DEBUG [com.test.XMPPHandler] - Session Created
DEBUG [com.test.XMPPHandler] - Message Sent: stream:stream
xmlns=jabber:client to=jabber.org
xmlns:stream=http://etherx.jabber.org/streams; xml:lang=en
version=1.0
DEBUG [org.apache.mina.filter.codec.ProtocolCodecFilter] - Processing
a MESSAGE_RECEIVED for session 1
DEBUG [com.test.XMPPHandler] - Session Idle

The ProtocolCodecFilter claims that it is processing the data, but my
handler never receives it. I managed to monitor the incoming data
using Wireshark, and it looks as expected. I only have one codec which
is added in the handler under the sessionOpened method like:

session.getFilterChain().addLast(codec, new ProtocolCodecFilter(new
TextLineCodecFactory(Charset.forName(UTF-8;

What would be the reason for this?
  



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Re: The performance of mina

[Emmanuel Lecharny]

xmuysa wrote:
 Hi,

 In our project,we need the performance of socket more than 500tps,
   
FYI, on my laptop, I get 4500 LDAP requests per second using Apache
Directory Server, and we went up to 13 000 requests per second on a 4
way CPU computer. And trust me, LDAP is a pretty expensive protocol. (we
are using MINA 2.0)

Looking at your base config, I see nothing wrong about it. Now, you have
many areas where you'll like to check :
- Handler : no matter what you do with MINA, Handler is where the CPU is
eaten. The ration Handler/MINA is probably something like 95%/5%. Check
your handlers to see if this is not the place you can get some
performance improvement
- Network : slow network, firewall, badly configured routers, are also
another performance killer.

This is pretty much all I can tell you so far.

But in any case, 500 Tps is basically not a problem for MINA *alone*.
Check your own code or your network...

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Re: Multiple Messages being recieved at the same time..

[Emmanuel Lecharny]

Mark Wallsgrove wrote:

Hey,

Thanks for the quick replies. Surely this isn't due to fragmentation?
Wouldn't fragmentation come down to multiple reads per network packet
being sent? Which would be fine, but all the messages that are being
sent fit within a single tcp/ip packet and are being received as a
single packet.
  
No. You have no reason to think that when you read a socket you will 
have only one single message in it. In fact, you have to iterate in your 
codec until you have nothing more to process.


This is the very essence of TCP/IP. Deal with it...

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Re: Multiple Messages being recieved at the same time..

[Emmanuel Lecharny]

On Sat, Nov 14, 2009 at 2:44 PM, d...@xx d...@proxiflex.fr wrote:
 Well it is difficult to use Mina if you don't know how socket are working...

 When you buy a car, how to drive a car is not explained in the car
 documentation !


How strange ... ;-)

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Re: Stackoverflow and inifinite loop when sending a message

[Emmanuel Lecharny]

Mathieu Sacrispeyre wrote:

Hello,
  

Hi,

I have a project which is working fine with mina 2.00 M5 and serial 
transportation.
I tried to update to rc1 but it do not work anymore.

There is an handler that adds a protocol codec filter to the 2 placed by its 
superclass in the filterchain of the session.
Something like this :
connector.getFilterChain().addLast(PROTOCOL_NAME_TRANSPORT,
new ProtocolCodecFilter(new TransportProtocolCodecFactory()));
connector.getFilterChain().addLast(PROTOCOL_NAME_BUSINESS,
new ProtocolCodecFilter(new BusinessProtocolCodecFactory()));

Then in the child handler :
connector.getFilterChain().addBefore(ADlMinaHandler.PROTOCOL_NAME_HIGH,
PROTOCOL_NAME_INTERMEDIATE, intermediateProtocolCodecFilter);

With the rc1 version when calling session.write, it ends with a stackoverflow 
iterating on these lines :
at 
org.apache.mina.core.filterchain.DefaultIoFilterChain.callPreviousFilterWrite(DefaultIoFilterChain.java:508)
at 
org.apache.mina.core.filterchain.DefaultIoFilterChain.access$7(DefaultIoFilterChain.java:502)
at 
org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.filterWrite(DefaultIoFilterChain.java:807)
at 
org.apache.mina.filter.codec.ProtocolCodecFilter$ProtocolEncoderOutputImpl.flushWithoutFuture(ProtocolCodecFilter.java:435)
at 
org.apache.mina.filter.codec.ProtocolCodecFilter.filterWrite(ProtocolCodecFilter.java:301)

It seems that it is looping on the business and intermediate protocol filters 
without any call to the transport one : the content of the resulting 
filterchain or the way entries are iterated may have changed between the 2 
versions...?

Before having a deeper look at the issue, I wanted to know/confirm :
- if this is a known issue (haven't seen something about that on this mailing 
list...)
  

No, AFAICT

- if the use of mina described here is correct
  

Enqueueing two codecs is a bit courageous...

It's difficult to say what's going on at this point. Can you create a 
JIRA and attach a minimal sample for us to test it ?


Thanks !

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Re: Stackoverflow and inifinite loop when sending a message

[Emmanuel Lecharny]

Mathieu Sacrispeyre wrote:

I agree with you : my code is working well with the previous version so I would 
be disappointed not to be able to use it anymore
In my case, passing an IoBuffer to the upper codec isn't so annoying even if it 
sounded a bit strange at the beginning.

  
I have a patch for this problem, if anyone want to test it (applicable 
on 2.0-RC1)  (remove the  XXX  lines ):


 start after this line 
Index: 
core/src/main/java/org/apache/mina/filter/codec/ProtocolCodecFilter.java

===
--- 
core/src/main/java/org/apache/mina/filter/codec/ProtocolCodecFilter.java
(revision 881795)
+++ 
core/src/main/java/org/apache/mina/filter/codec/ProtocolCodecFilter.java
(working copy)

@@ -53,10 +53,10 @@
private static final Class?[] EMPTY_PARAMS = new Class[0];
private static final IoBuffer EMPTY_BUFFER = IoBuffer.wrap(new 
byte[0]);


-private static final AttributeKey ENCODER = new 
AttributeKey(ProtocolCodecFilter.class, encoder);
-private static final AttributeKey DECODER = new 
AttributeKey(ProtocolCodecFilter.class, decoder);
-private static final AttributeKey DECODER_OUT = new 
AttributeKey(ProtocolCodecFilter.class, decoderOut);
-private static final AttributeKey ENCODER_OUT = new 
AttributeKey(ProtocolCodecFilter.class, encoderOut);
+private final AttributeKey ENCODER = new 
AttributeKey(ProtocolCodecFilter.class, encoder);
+private final AttributeKey DECODER = new 
AttributeKey(ProtocolCodecFilter.class, decoder);
+private final AttributeKey DECODER_OUT = new 
AttributeKey(ProtocolCodecFilter.class, decoderOut);
+private final AttributeKey ENCODER_OUT = new 
AttributeKey(ProtocolCodecFilter.class, encoderOut);
   
/** The factory responsible for creating the encoder and decoder */

private final ProtocolCodecFactory factory;
@@ -210,7 +210,7 @@
}

IoBuffer in = (IoBuffer) message;
-ProtocolDecoder decoder = getDecoder(session);
+ProtocolDecoder decoder = getDecoder0(session);
ProtocolDecoderOutput decoderOut = getDecoderOut(session, 
nextFilter);
   
// Loop until we don't have anymore byte in the buffer,

@@ -288,7 +288,7 @@
}

// Get the encoder in the session
-ProtocolEncoder encoder = getEncoder(session);
+ProtocolEncoder encoder = getEncoder0(session);

ProtocolEncoderOutput encoderOut = getEncoderOut(session,
nextFilter, writeRequest);
@@ -322,7 +322,7 @@
public void sessionClosed(NextFilter nextFilter, IoSession session)
throws Exception {
// Call finishDecode() first when a connection is closed.
-ProtocolDecoder decoder = getDecoder(session);
+ProtocolDecoder decoder = getDecoder0(session);
ProtocolDecoderOutput decoderOut = getDecoderOut(session, 
nextFilter);
   
try {

@@ -488,16 +488,6 @@
}

/**
- * Get the decoder instance from a given session.
- *
- * @param session The associated session we will get the decoder from
- * @return The decoder instance
- */
-private ProtocolDecoder getDecoder(IoSession session) {
-return (ProtocolDecoder) session.getAttribute(DECODER);
-}
-
-/**
 * Dispose the decoder, removing its instance from the
 * session's attributes, and calling the associated
 * dispose method.
@@ -534,6 +524,28 @@
return out;
}

+private ProtocolEncoder getEncoder0(IoSession session) throws 
Exception {

+ProtocolEncoder encoder = (ProtocolEncoder) session
+.getAttribute(ENCODER);
+if (encoder == null) {
+encoder = factory.getEncoder(session);
+session.setAttribute(ENCODER, encoder);
+}
+return encoder;
+}
+
+private ProtocolDecoder getDecoder0(IoSession session) throws 
Exception {

+ProtocolDecoder decoder = (ProtocolDecoder) session
+.getAttribute(DECODER);
+   
+if (decoder == null) {

+decoder = factory.getDecoder(session);
+session.setAttribute(DECODER, decoder);
+}
+   
+return decoder;

+}
+
private ProtocolEncoderOutput getEncoderOut(IoSession session,
NextFilter nextFilter, WriteRequest writeRequest) {
ProtocolEncoderOutput out = (ProtocolEncoderOutput) 
session.getAttribute(ENCODER_OUT);

 End before this line 

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Re: Custom messageSent

[Emmanuel Lecharny]

Pavel Zdenek wrote:

2009/11/23, Emmanuel Lecharny elecha...@apache.org:
  

Pavel Zdenek wrote:


Greetings fellow min(a)ers!

I understand the controversy over messageSent,  because the feature
of firing twice per each actual object being encoded is annoying me as
well. Anyway, i do need such sort of event information in my current
pet project, something has to happen in the persistent layer after the
message delivery is confirmed. Unfortunately, the most recommended
hack solution with waiting on WriteFuture is neither applicable,
because i do physically send out a multiple IoBuffers for each
abstract message written. I need to get the messageSent on the last
one, not the first one (as it happens now). I am thinking about
setting up a wait condition after session.write and signalling it from
the correct messageSent. But i am too unfamiliar with the threading
model of Mina, to say whether it's a good idea. Somebody with better
understanding say?

  

The way it works is that each 'message' is enqueued until it's sent.
Then a MessageSent event is generated. Sadly, we don't associate a umber
with each message, so it's difficult to correlate a MessageSent event
with a given message, except that AFAIR, the IoBuffer is present in the
messageSent event.

If so, you may be able to compare the message content with what you know
to be the last message sent (you can store it in the session for
instance). This is from the top of my head...



Fortunately my protocol is strictly synchronous request/response, so
the message matching will be much easier. Safety question: may it
happen, that the session handling (which writes a response object into
the session) will be the same thread as the one which initiates
messageSent? From my observation, this is not the case, but i prefer
asking first and shoot a code later...
  
It depends if you have an executor in your chain. If you don't, then 
every message processing for a session will be processed by a single 
thread : the one associated with the IoProcessor (as the IoProcessor 
holds the selctor, it makes sense).


Now, if you have an executor, you may have a message processed by 
different threads, as the exector acts as a demultiplexer : it picks a 
thread in the pool and ask it to process the message. If your executor 
is used in both side (you can perfectly ask the executor not to be used 
when writing messages), then another thread will e used to write the 
message (not sure what will be the impact though ...)

Is there any document describing the threading model of MINA? I
remember seeing some comprehensive picture about Netty, long time
ago...
  
Time's flying ... There are a few slides available, not sure if they are 
accurate.


At some point, we should write some samples to demonstrate the different 
use cases.

Thanks a lot,

Pavel Z.

  



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Re: Miserable performance results from MINA 1.1.7

[Emmanuel Lecharny]

Can you add this line in your server :

((SocketSessionConfig) acceptor.getSessionConfig()).setTcpNoDelay(false)

and see if it makes any difference ?



Zvika Gart wrote:

Sorry, but Nagle doesn't have anything to do with this...
Nagle is relevant at the *client side* when sending small buffers over the
network.
My client is a simple C# program (not MINA, so SocketConnector is
irrelevant) that sends large buffers (100KB) at each call to Socket.Send()
If Nagle was to blame then I would see the same bandwidth from both server
implementations. This is not the case.


On Tue, Nov 24, 2009 at 8:41 PM, Emmanuel Lecharny elecha...@apache.orgwrote:

  

Damn Nagle ! ( http://en.wikipedia.org/wiki/Nagle_algorithm )

Check the FAQ : http://mina.apache.org/faq.html (


Why does SocketConnector send several messages as one message?)



Zvika Gart wrote:



Hello,
Please help, as this is too strange to be true...

I'm comparing two implementations of the most basic socket server - it
listens for a client, and after accepting it just starts reading data from
it.
The first implementation using Java's plain old ServerSocket:

   ServerSocket srv = new ServerSocket(80);
   Socket s = srv.accept();
   InputStream i = s.getInputStream();
   byte[] buf = new byte[1024 * 8];
   while (true) {
i.read(buf);
   }

The Second implementation using MINA 1.1.7 (which so simple that I can
paste
it here):

First the Main class:

package test;

import java.net.InetSocketAddress;

import org.apache.mina.common.ByteBuffer;
import org.apache.mina.common.IoAcceptor;
import org.apache.mina.common.SimpleByteBufferAllocator;
import org.apache.mina.transport.socket.nio.SocketAcceptor;

public class Main {
   public static void main(String[] args) throws Exception {
   // The following two lines don't help
ByteBuffer.setUseDirectBuffers(false);
   ByteBuffer.setAllocator(new SimpleByteBufferAllocator());

   IoAcceptor acceptor = new SocketAcceptor();
   acceptor.bind(new InetSocketAddress(80), new MyHandler());
   }
}


And the IoHandler:


package test;

import org.apache.mina.common.IoHandlerAdapter;

public class MyHandler extends IoHandlerAdapter {

}


I wrote a simple client that connects to the server and pumps continuous
data.
Both client and server run on Amazon's EC2 on Debian Linux instances
(64-bit, Java 1.6). Client is in Europe and server in USA.


*The results:*
Simple Java implementation - 5 Mbps
MINA implementation - 750 Kbps

Tried removing the setUseDirectBuffers lines; tried a simpler threading
model by running the IoHandler on the IoProcessor threads... nothing helps
-
MINA is capped at 750 Kbps.
What is going on here?!



  

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Re: Miserable performance results from MINA 1.1.7

[Emmanuel Lecharny]

Zvika Gart wrote:

The default is false...
I tried disabling Nagle by setting TcpNoDelay to true. As expected, this
didn't have any effect - the server doesn't send any data to the client,
only receives data.
  
Assuming that you are sending 8Kb buffers, anyway, it should not make 
any difference.


Now, I don't have the code in MyHandler, so it's difficult to see what 
you do there.


Also, have you tried with MINA 2.0.0-M6?

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Re: Miserable performance results from MINA 1.1.7

[Emmanuel Lecharny]

Zvika Gart wrote:

This is the code of my handler. It doesn't do anything. That's the point.
The server should just consume the data as fast as it can.
  
Interesting. I have to test this code on my computer to see exactly what 
can be the impact.


Can you add an executor in the filter cxhain to see if it improves the 
performance ?

Strangely enough, Mina 2.0 performs even worse then 1.1.7

Is there some problem in using Java nio on Virtualized machines?
  

Not that I know about. Anyone else ?

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MINA on Amazon EC2 : degraded performances observed, why ? (was Re: Miserable performance results from MINA 1.1.7)

[Emmanuel Lecharny]

Zvika Gart wrote:

The default threading model in 1.1.7 is to use the executor filter. I also
tried removing it. Both don't help.
  

Ok.

I tested this scenario using two PCs at the office connected with a
crossover cable. The MINA server is reaching the 100 Mbps link speed limit.
Why running on Amazon's instances yields such a poor performance??
  
Interesting. So MINA on a local network does works fine, and in Amazon, 
it's slow as a dog, when a standard ServerSocket is just plain ok.


I changed the subject so that those who have already used MINA on EC2 
can popup and give use some insight...


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Re: BufferUnderFlowException in org.apache.mina.filter.codec.ProtocolCodecFilter

[Emmanuel Lecharny]

Alexander Christian a écrit :

Hi guys,



snip/
I've no idea what causes this bufferunderflow. And i've no idea how to 
track down the root of this issue (the stack does only show mina 
classes ..).
Unchecked exception thrown when a relative get operation reaches the 
source buffer's limit. 


Basically, you try to do a get()on the IoBuffer but there is nothing 
left into it.


Remember that you may perfectly receive your message in small pieces, 
and you will have to reassemble them before being able to decode it.

Re: Who is the author of AbstractPollingIOProcessor.java?

[Emmanuel Lecharny]

Hi,

more inline

zswallow a ??crit :
I use mina-2.0.0-RC1 to recv media data(TCP/IP) and immediately send it out. 
I set 2 NioProcessor, one is for recving data, the other is for sending the recved data.
  


Hmmm... Can you post the code ? It's a bit strange, I don't see how you 
can dedicate a IoProcessor for send.


Why aren't you using a Connector in this case ?

snip/
if it is a bug? 

Difficult to tell, just create a JIRA and attach the offending code.



Anyone can help me with this, or contact the author of 
AbstractPollingIOProcessor.java?
  
You are on the right place. No need to contact someone specifically, as 
this code has been modified many times by many people (7 at least)...

Re: 2.0.0-RC1 bug? -- IoConnectot.dispose blocks forever?

[Emmanuel Lecharny]

Alexander Christian a écrit :

Hey there,

Am I the only one who faced this problem? No comments? No problems?
Is it possible that you provide a piece of code that demonstrate the 
problem ?


Thanks !

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Re: TCP half-open connection question

[Emmanuel Lecharny]

Srikanth J a écrit :

Hi
I am facing a problem with tcp half-open connection.  Would really
appreciate any thoughts on the issue

The application uses mina tcp server (mina version - 1.1.7) with a
MLLP codec (MLLP codec is provided by apache-camel).  The problem is
that this application runs behind a hardware load balancer which does
a tcp half-open service ping to monitor if application is still
available.  The half-open involves load balancer sending a SYNC,
receiving the ACK from mina server, but not sending a ACK back (not
completing 3way hankshake) and then sending a Reset and FIN commands.
This is resulting in the following exception being thrown every time
half-open is done

org.apache.camel.CamelException: java.io.IOException: Connection reset
by peer (errno:232)
at 
org.apache.camel.component.mina.MinaConsumer$ReceiveHandler.exceptionCaught(MinaConsumer.java:90)
at 
org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.exceptionCaught(AbstractIoFilterChain.java:564)
at 
org.apache.mina.common.support.AbstractIoFilterChain.callNextExceptionCaught(AbstractIoFilterChain.java:345)
at 
org.apache.mina.common.support.AbstractIoFilterChain.access$1000(AbstractIoFilterChain.java:53)
at 
org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.exceptionCaught(AbstractIoFilterChain.java:643)
at 
org.apache.mina.common.IoFilterAdapter.exceptionCaught(IoFilterAdapter.java:75)
at 
org.apache.mina.common.support.AbstractIoFilterChain.callNextExceptionCaught(AbstractIoFilterChain.java:345)
at 
org.apache.mina.common.support.AbstractIoFilterChain.access$1000(AbstractIoFilterChain.java:53)
at 
org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.exceptionCaught(AbstractIoFilterChain.java:643)
at 
org.apache.mina.filter.executor.ExecutorFilter.processEvent(ExecutorFilter.java:224)
at 
org.apache.mina.filter.executor.ExecutorFilter$ProcessEventsRunnable.run(ExecutorFilter.java:264)
at 
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
at 
org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:51)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.io.IOException: Connection reset by peer (errno:232)
at sun.nio.ch.FileDispatcher.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233)
at sun.nio.ch.IOUtil.read(IOUtil.java:200)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:207)
at 
org.apache.mina.transport.socket.nio.SocketIoProcessor.read(SocketIoProcessor.java:218)
at 
org.apache.mina.transport.socket.nio.SocketIoProcessor.process(SocketIoProcessor.java:198)
at 
org.apache.mina.transport.socket.nio.SocketIoProcessor.access$400(SocketIoProcessor.java:45)
at 
org.apache.mina.transport.socket.nio.SocketIoProcessor$Worker.run(SocketIoProcessor.java:485)
... 2 more

Is this a known issue (i did look up the mail archive and did some
googling, dint find much) or is this happening because of any possible
wrong configuration of mina?
  


Sounds to me plain normal, as soon as the load balanced send a badly 
crafted message to the stack. You want your handler to know that the 
connection has been brutally terminated, in order to close the session 
and free all the resources you have allocated for this session, no ?


Check on the load balancer side to see if it can send something a bit 
smarter.


Another possibility would be to tune the MLLP codec to handle such a 
terminaison.


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Emmanuel Lécharny
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Re: slow performance with large messages

[Emmanuel Lecharny]

Hi,

please mention the MINA version you are using when psoting a question...

Comments inline.

Simmons, Aaron a écrit :

I am implementing a mina server for a protocol that can sometimes send very large 
messages (250K).  I've noticed that receiving these messages can be very slow 
(12s).

This performance is surprising, as I can transfer a 250K file to this same 
server via scp or netcat in under 1.5s.
  
There is an issue with the way we handle the sendBufferSize, it's 
initial size is small (8192 bytes), and should be set to the system 
default. See DIRMINA-651 for more information.


You can change this value before opening the acceptor, by injecting the 
desired value in the SessionConfig object. Something like :


final IoAcceptor acceptor = new NioSocketAcceptor();
acceptor.getSessionConfig().setSendBufferSize( whatever fits you );
...



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Re: slow performance with large messages

[Emmanuel Lecharny]

Simmons, Aaron a écrit :
You can change this value before opening the acceptor, by injecting the 
desired value in the SessionConfig object. Something like :


final IoAcceptor acceptor = new NioSocketAcceptor();
acceptor.getSessionConfig().setSendBufferSize( whatever fits you );
...



Hmm, according to the docs for ISessionConfig here
   http://mina.apache.org/report/trunk/apidocs/org/apache/mina/core/session/IoSessionConfig.html

there's no setSendBufferSize.  Perhaps you meant setReadBufferSize?


  
As inconsistent it may sounds, the class you want to look at is 
SocketSessionConfig, not inheriting from IoSessionConfig... Don't ask my 
whay ;)



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Re: slow performance with large messages

[Emmanuel Lecharny]

Simmons, Aaron a écrit :
There is an issue with the way we handle the sendBufferSize, it's 
initial size is small (8192 bytes), and should be set to the system 
default. See DIRMINA-651 for more information.



I looked up DIRMINA-651 (Data Race in 
org.apache.mina.core.session.AbstractIoSession).  I'm not sure I see how this 
relates to the buffer size?
  


Sorry, my pomcuter is dilesxic.  
http://issues.apache.org/jira/browse/DIRMINA-561



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Re: Client Inrush

[Emmanuel Lecharny]

Christopher Popp a écrit :

Hi,
  

Hi,

comments inline

I wanted to get some feedback. (MINA 2.0.0 M6).

We're currently doing inrush testing of clients against our mina based 
application.  We're able to have 1024 clients connect in roughly simultaneously 
(30 second window), however we're not able to get our system to stabilize when 
doing 2048 or 4096 simultaneous clients.

On connection, there is an exchange of messages between the client and server, and a couple database calls that take place per client. 
Blind guess : a couple of database calls will most probably be the 
contention point in your system. From some tests I conducted with 
Oracle, a request/response loopback with a DB costs a few ms. Even f it 
sounds a small number, this is a clear limitation when you don't have 
tens of CPU...


But this is just a blind guess. My advice here would be to use a 
profiler to check what's going on exactly. Another option would be to 
mockup the DB and see how MINA will behave when you have moved aside the 
potential costly operations.



 We also have application level keep-alives that we need to send out, otherwise 
the device will disconnect.  Our keep-alive filter basically implements the 
sessionIdle method, and when it expires for the server, we write a keep-alive, 
and when it expires for the device, we disconnect the device.

Based on a network trace, we are not seeing keep-alives sent out when they 
should be under this load.  Our presumption is that this is due to mina's 
worker threads being too busy with database processing and such.

acceptor = new NioSocketAcceptor(Runtime.getRuntime().availableProcessors() + 
1);
acceptor.getFilterChain().addLast(protocol, new ProtocolCodecFilter(new 
XXCodecFactory()));
acceptor.getFilterChain().addLast(threadPool, new 
ExecutorFilter(workerThreadPool));
acceptor.getFilterChain().addLast(keepAlives, newXXKeepAliveFilter(new 
MTKeepAliveMessageFactory());
acceptor.setHandler(devHandler);
  
During these tests we were using the default constructor for the ExecutorFilter, limiting us to 16 worker threads.  We have since changed this to be configurable and will bump the number of threads up quite a bit.  We're expecting this to improve the situation quite a bit.  However, it seems that if for whatever reason this constant number of threads get tied up doing work, our keep alive processing will halt, and clients will disconnect which eventually could cause a cyclic destabilizing of the system.
  

Again, profiling the application could help here.

What would be nice is to be able to have a set of threads that are dedicated to 
handling keep-alives.  One thing I thought of is to add another ExecutorFilter 
dedicated to handling SESSION_IDLE events, similar to what is shown in the 
javadocs for WRITE IoEvents in the javadocs.  This way, a thread should still 
pass on the SESSION_IDLE events to the keep alive filter we have.  Some 
questions about this though.  If from the idle event in the keep alive filter I 
attempt to write the keep alive, will this end up being blocked due to the fact 
that there are no extra threads from the main executor available?  (And hence, 
I actually need two extra executor filters...one for SESSION_IDLE and one for 
WRITE).  And if I decide to add these extra executor filters, where should they 
go in the filter chain in relation to the other executor filter?  It just seems 
that if an executor is out of threads, it would block the filter chain 
regardless of whether there is an
 executor earlier on in the chain that has contributed a thread.  I would have 
to assume this is handled somehow though.

Also, is there any benefit to increasing the number of IO processor threads to more than the number of cores + 1?  
I don't think so, as soon as you have an executor in the chain. The 
IoProcessor is the class which manage the selector, and I'm not sure 
that having many selectors can help. However, I have no metric on that ...



I read that as the suggested starting point, but in the somewhat outdated 
documentation on the threading model, 
(http://mina.apache.org/configuring-thread-model.html), it is stated the a 
newCachedThreadPool is suggested for IoServices.
  
yeah, it's totally outdated and need to be improved A LOT. In fact, we 
need to conduct some extensive tests and see what could be the best 
configuration for a different set of use cases...


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Re: Some writes observed to stall until select times out

[Emmanuel Lecharny]

Ok.

Create a JIRA, not sure someone can check the code in the next couple of
days, so with a JIRA, it won't be forgotten !

Thanks !

On Wed, Dec 30, 2009 at 2:40 AM, John Fallows john.fall...@kaazing.comwrote:

 On Tue, Dec 29, 2009 at 3:10 PM, Emmanuel LŽcharny elecha...@gmail.com
 wrote:
  John Fallows a écrit :
 
  Folks,
 
  We have observed an issue in Mina 2.0-M4 where TCP writes are not
  flushed to the network even though the receiver is keeping up and CPU
  has low utilization.
 
 
  Please confirm that it's still an issue with 2.0-RC1. We have released 3
  versions since M4...
 

 Confirmed, 2.0.0-RC1 exhibits the same behavior as 2.0.0-M4 for this
 scenario.

 The previously proposed 2.0.0-M4 fix of removing the needsWakeup check
 from AbstractPollingIoProcessor.flush() also resolves the issue for
 2.0.0-RC1.

 Kind Regards,
 John Fallows
 --
 | Kaazing Corporation |
 John Fallows | CTO | +1.650.960.8148
 888 Villa St, Ste 410 | Mountain View, CA 94041, USA




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Cordialement,
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Re: message process order

[Emmanuel Lecharny]

hakan eryargi a écrit :

hi,

how can i guarantee messages are processed in arrival order and
sequantially (one is processed after previous is completed) for
NioSocketAcceptor ?
  
This is guaranteed, as soon as you don't inject an ExecutorFilter in 
your chain (see [1] for more info about this point). The way incoming 
messages are processed by MINA is pretty simple : each opened socket is 
associated with a selector, itself associated with a IoProcessor. 
IoProcessor uses a single thread to process this message, but to insure 
some scalability, we spawn more than one IoProcessor, and we also use a 
queue (the backlog) for messages waiting to be processed when the thread 
is busy. So the order will always be respected, as the next message can 
only be processed when the current message has been completely processed.


The biggest issue with this approach is that each message is considered 
having the very same priority, and a message neeeding a long processing 
will block all the other messages. More important, you will block 
messages from other sessions too. That's painful, and this is one of the 
reason the ExecutorFilter has been added.

i guess, as tcp guarantees packet order, for each IoSession message
order is guaranteed. but if messages are passed to IoHandler in a
multi-threaded manner there could be cases process order is different
from arrival order.
  
[1] This is where the ExecutorFilter comes into the picture : it creates 
a way to process more than one message at the time (or kind of...). The 
drawback is that you may have more than one message of a specific 
session being processed in parallel. This can be avoided by teling the 
ExecutorFilter to use a OrderedThreadPoolExecutor.


Hope it helps.

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Re: MINA hanging onto dead connections?

[Emmanuel Lecharny]

Laurent Cohen a écrit :

Hello all,

Typically, a technique that I've implemented was using the fact that, 
when the remote peer is disconnected for any reason, the corresponding 
SelectionKey on the server becomes readable().

Even when the client hasn't sent a FIN ?
It is possible to use this when you know for example that the 
connection should be either idle or waiting for the server to send 
something. In this case, you just need to add OP_READ to the 
operations the key is interested in.
For instance, if an idle connection becomes suddenly readable - as in 
SelectionKey.isReadable() - then it means it is disconnected.

Well, I would rather bet that this means something has to be read.
For this to apply, you also need to keep some state attached to the 
SelectionKey, so that you know that it is readable when it shouldn't.
I'm not sure I grok what you says her, but may be I need a coffee or 
two... (just woke up).


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Re: 2.0.0-RC1 bug? -- IoConnectot.dispose blocks forever?

[Emmanuel Lecharny]

https://issues.apache.org/jira/browse/DIRMINA-755 created :)

You can add you as a follower, you'll receive any update on this issue 
automatically.


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Re: mem leak?

[Emmanuel Lecharny]

David Rosenstrauch a écrit :

On 01/13/2010 03:39 AM, Emmanuel LŽcharny wrote:

vagrant1984 a écrit :
We are currently using MINA 2.0.0-M6. 
The current version is 2.0.0-RC1, please switch to this version as 
many bug fixes has been injected into the code.


I've actually been holding off on upgrading us off of 2.0.0-M6 - since 
2.0 is in release candidate mode, I figured that a true 2.0 was 
coming soon.
Totally agree, if your program works. But if you have issues, then it's 
better to check with the most recent version to see if those issues are 
still present.




Just wondering what the dev roadmap is and when a 2.0 release might be 
coming?
We are trying to cleanup the remaining bugs atm - call it bug parade - 
in order to be able to vote a 2.0 (next week ?)


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Re: Connection reset by peer

[Emmanuel Lecharny]

Ted Yu a écrit :

Hi,
I saw this snippet in our server log many times:

  

snip/

java.io.IOException: Connection reset by peer
  

/snip


If someone has seen such stack trace, please share how to fix the problem.
  
Very simple : stop accepting clients who evily disconnect without notice 
! Bad, bad clients ... I *always* close a socket correctly, never 
slamming the door, even if my computer stops because of a power shutdown...


More serioulsy, it's just an information that a client has quit 
brutally. There is nothing to fix here, except logging less.



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Re: supporting multiple clients with MINA

[Emmanuel Lecharny]

Christopher Popp a écrit :

Emmanuel Lcharny wrote:
  

That would be crazy :)

Really, MINA does that for you. One simpe rule: one client, one session. One 
hundred thousands clients, one hundred thousands sessions (it has been tested 
up to these numbers ;)




Out of curiosity, how was a test of one hundred thousand clients performed on a machine with a 65k socket limit? 
You can handle more than 65k sockets on a server (at least on a Unix 
based server), I don't know about W$).
 Did the server bind to multiple addresses?  We just had a test proceed with some success with 128k sessions across our cluster, but this is across 8 servers  (16k sessions each) built on MINA, and each JVM sharing some information through Terracotta. 
I guess that if your servers get loaded, you must spread the sessions on 
multiple machines. What kind of oad do you see on those machines ?

 We've only ran into one problem that has eluded us so far that seemingly 
causes all of the sockets in use by our JVM to get messed up, causing MINA 
sessions, the Terracotta client connection, and our database connections to be 
lost.  We're running the tests with instances on Amazon EC2, so one thing we're 
going to try is running it on some physical servers.  Some blogs regarding 
network performance of Amazon EC2 have been less than stellar in their reviews 
of it, and we're being pretty tough on them.
  
We certainly would be interested to get some numbers from 'the real 
world' :) If you can share some information on your MINA usage here, 
that would help us to see how far we can go with MINA : many people are 
asking us what kind of performance MINA can provide in such env.


Thanks !
  
  



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Re: supporting multiple clients with MINA

[Emmanuel Lecharny]

Michael Clifford a écrit :
Hello.  I've started playing around with storing data as attributes in the session object.  That's really useful.  :-)  And you had suggested storing the string that comes through in the session as a session attribute.  What I'm wondering is if there might be a more efficient way to do this.  
When a session gets a received message, the messagereceived method receives both the session and an object containing the message.  Is that object already part of the session, or was it already extracted? 

It's not part of the session.

 If it is still inside the session, maybe I can save myself the step of copying 
it to an attribute in the session.
  
Really, I don't have a clue about what you are trying to do here. 
Keeping something as a Session's Attribute is just a convnien way to get 
it stored somewhere you can get it from when your application needs it. 
Now, it's up to you to store it on the file system or on any storage you 
want to use.



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Re: BlacklistFilter

[Emmanuel Lecharny]

jose vilmar estacio de souza a écrit :

One more question please.
Looking at class BlackListFilter I saw that the locking mechanism was 
implemented in all routines, sessionCreated, sessionOpened, 
sessionClosed, sessionIdle, messageReceived and messageSent.


I think that would be sufficient to implement in the method 
sessionCreated. Is it true or am I missing something?


Assming you can block a session at any time sinc eit began, we have to 
check for this status for any message received. The question would be : 
should we close a session instead of bocking it ?



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Re: MINA 2.0 RC code base stability?

[Emmanuel Lecharny]

Michael Clifford a écrit :

I'm doing pretty well using the MINA 1.1 code base, but it looks like some of 
the examples require the use of 2.0.  I'm a bit worried about the note that 
says that 2.0 is bleeding edge code though.
That simply mean it's the code we are working on. There haven't been a 
patch on MINA 1.1 for more than one year now (almost 2), and no release 
too. I don't think there will be any in the next few years.
  How stable is it right now?  

Stable. No API modification, only bug releases.

Am I likely to run into any problems using the 2.0 framework?
It depends on which feature you use. For standard usage,  it should work 
just fine.
  As far as I know, I don't need anything specific to 2.0 right now.  However, I am trying to write a client to go with my server, and the client examples appear to require 2.0.  So is it safe to use it?  :-) 
yes. But there is nothing you can do with MINA 2.0 you can't do with 
MINA 1.1.7. You just have to convert the examples to MINA 1.1.7.

 Are any interfaces likely to change before release?

NO (big no). API has been frozen.

  Are there any issues to be aware of at this point that would make it worth 
sticking with 1.1 instead?
  
Not that I know. Some majot bugs have been fixed since %INA 1.1.7, and 
in any case, I would rather use MINA 2.0 than MINA 1.1.7.



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Re: sorry, I'm not able to convert byte into myClass

[Emmanuel Lecharny]

Hi,

in the first case, you can set the position in the byteBuffer using the
position()  method.

However, you will have the exact same problem than in case 2 : you will get
a BufferUnderflow for the same reason  :

a call to in.hasRemaining() does not tell you that you hace enough bytes to
be able to decode a new BasicMessage. It just tells you that you have
*some*  bytes available.

From the top of my head, I think you can call in.hasRemaining( expectedSize
)

On Sun, Feb 7, 2010 at 11:48 AM, silviasignor...@libero.it 
silviasignor...@libero.it wrote:

 Dears,
 I've the same problem...
 I have a mina peer that communicate with myClass called BasicMessage.

 My problem is on decoder filter in fuction doDecode(), I convert the
 message
 into byte and receive the corret byte, but I'm not able to convert it into
 BasicMessage.
 I try two solution:

 FIRST SOLUTION My problem is that the program print line 
 many times, I
 belive that host receive the message many times because array() will not
 move
 forward in the IoByteBuffer. Is there a fuction that cancel the
 IoByteBuffer?

 public class MessageDecoder extends CumulativeProtocolDecoder {

protected boolean doDecode(IoSession session, IoBuffer in,
 ProtocolDecoderOutput out) throws Exception {
byte[] byteVal = null;
if (in.hasRemaining()){
byteVal = in.array();
BasicMessage m = createBasicMessage(byteVal);
System.out.println(RICEVUTO DA  + m.getSender() +
 \n);
out.write(m);
in.get();
return true;
} else {
return false;
}
}

public static BasicMessage createBasicMessage(byte[] bytes){
Object object = null;
try{
object = new java.io.ObjectInputStream(new java.io.ByteArrayInputStream
 (bytes)).readObject();
}catch(java.io.IOException ioe){
java.util.logging.Logger.global.log(java.util.logging.Level.SEVERE, ioe.
 getMessage());
}catch(java.lang.ClassNotFoundException cnfe){
java.util.logging.Logger.global.log(java.util.logging.Level.SEVERE,
 cnfe.
 getMessage());
}
return (BasicMessage)object;
}
 }




 SECOND SOLUTION In this case the receiver throws the exception
 org.apache.
 mina.filter.codec.ProtocolDecoderException:
 java.nio.BufferUnderflowException
 (Hexdump: AC ... 72).

 protected boolean doDecode(IoSession session, IoBuffer in,
 ProtocolDecoderOutput out) throws Exception {
byte[] byteVal = new byte[in.capacity()];
if (in.hasRemaining()){
in.get(byteVal , 0, in.capacity());
BasicMessage m = createBasicMessage(byteVal);
System.out.println(RECEIVED FROM  + m.getSender()
 +
 \n);
out.write(m);
return true;
} else {
return false;
}


 Thanks
 Sia




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Re: mina 2.0 time estimate

[Emmanuel Lecharny]

On 2/8/10 12:33 PM, Harsha Sri-Narayana wrote:

Is there a time estimate for when mina 2.0 will be released?
   

H... When it's ready !

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