Jeff Genender wrote:
Hi Jules.
A few comments. First, you made changes without discussing them on the
dev lists.
There has been lots of discussion over the past week or two on both
geronimo-dev and wadi-dev - I took this, along with my own findings when
I looked at the code, and further offline discussion with Jan and Greg
as we were making the changes, into account.
As I have clearly stated, if you don't like the way it has been done, it
is only an iteration towards a final solution and you are welcome to
contribute codewise. It is a major step forwards as it unifies the way
that this is done between both containers, and further allows the use of
clustering solutions other than WADI.
As per the discussions in the past, both Aaron and David Jencks, as well
as I threw in our .02 on how to integrate the clustering. I would
appreciate you discuss code ideas and changes
I was involved in the recent threads (I started them and stoked them)
and did discuss these issues. Please check the archive. To say that I
was not open to discussion is not a tenable position.
that have such a drastic
impact on the Geronimo code base.
Drastic ? It extends Geronimo to be able to run the WADI demo webapp,
with no impact whatsoever on any non-distributable webapp.
Here are the issues with your check in:
1) I explained before for Jetty, and obviously now I need to do it for
Tomcat, a -1 on Axion as a dependency. There should not be any web
application dependencies injected at the container level. This means
there is a severe architectural issue with WADI when we are injecting
these dependencies into the container.
It is no longer an app dep - it is a container dep. The decision to use
WADI is now made by the container, and as stated in my mail to the list,
the config which determines this will soon move from the app to the
container.
I have also invited you to work on removing this dep from WADI.
2) You hard coded in org.codehaus.wadi.tomcat55.TomcatManager as the
distributablesession manager in the TomcatContainer. Hardcoding a
pluggable session engine is very bad, and defeats the pluggability of a
configuration that we requested.
Jeff, please take the time to read, run and understand the code before
judging it.
As stated in my mail, a sensible default distributable session manager
is hardcoded. This is overridable in the tomcat or jetty plan. This is a
pretty standard way of doing things and means that any session manager,
not just WADI may now be selected. This is a great step forward over the
previous version where an important method signature included the
WADIGBean type, which restricted distributable webapps to WADI and not
other possible alternatives.
3) You placed log.info() in the code, and Aaron worked pretty hard to
clean those up.
I shall downgrade the level - apologies to Aaron - as I stated, this
code is only an iteration towards a finished product.
4) Your integration of setting the manager (no matter what) is a direct
clash with the
with the..... what ?
Jules, I am giving a complete -1 of checkin of 368344. These are all
for technical reasons. Please back out these changes, and bring this
discussion to the Geronimo lists as this needs some significant
discussion for implementation. I would appreciate that you please
involve the Apache way and open discussions on the lists before doing
this sort of thing in the future.
Of the three reasons that you have given 2 are completely mistaken and
one is trivial - in my book, insufficient technical argument for the
rejection of a significant enhancement.
Again, I will CC the G lists to make this clear, that I would like this
change backed out.
In conclusion my change should remain for the following technical reasons.
- it fixes something that was broken
- it unifies two separate approaches into a single, more manageable
approach, without sacrifice.
- it moves us in an agreed direction (from per-app to per-container
based configuration)
- it is simpler than what it replaces - it frees us from requirements
for an extra GBean and divergent Jetty and Tomcat geronimo-web.xml schemas.
- it is more flexible than the code that it replaces - it allows
selection of ANY session manager, NOT JUST WADI, as was previously the case.
- it is small.
On the non-technical side of things:
- preceding this change, possible solutions were discussed on relevant
dev lists at length.
- 3 Geronimo/WADI committers were involved in and agreed on the final
minutiae of the change.
- by fixing, simplifying and unifying the WADI/Geronimo integration,
this changes brings significant benefit to Geronimo.
If there are aspects of the change that you do not like, then we should
simply work together, on top of the change, to resolve these issues.
By backing out the change, you break something that is fixed and remove
all the beneficial code that you did not have issues with. If there are
small issues, such as the level of a log message, then we should simply
fix it and continue in a forward direction.
regards,
Jules
Jeff
Jules Gosnell wrote:
Here is a list of outstanding issues associated with this work:
- ActiveMQ's shutdown hook seems to trigger when Geronimo is shutdown,
removing AMQ before WADI - WADI doesn't like this. I have added a
property to the node.sh script which suppresses this behaviour. I will
document it in the Getting Started doc.
- There 'may' be issues with nodes finding each other, when a Geronimo
node is introduced into a WADI cluster - investigating.
- Jeff - you should look over the changes and make sure that they do not
impact on any other TC fn-ality. They were done with Emacs, so the
formatting may be offensive. Please feel free to make them your own and
bring any issues back to the list. The WADIGBean, is no longer used, so
you may want to remove this from the repo.
- Jan and Jeff - since this config is now done on the container bean and
not in the geronimo-web.xml, you may no longer need to implement your
own geronimo-web.xml schemas (I haven't looked very closely at TC). You
may want to consider this and perhaps lose them.
- In order to get the same webapp to work in all containers
(tomcat5[05], jetty[56], geronimo-[tomcat/jetty], jboss-tomcat), I had
to move deps back to Geronimo container-level. These include Axion,
which I know will upset Jeff. As I have stated before, WADI's dependence
on Axion is easily removed. If Jeff or anyone wants to look at replacing
it with Derby, it is fine with me, as long as they do some testing and
confirm that having created a session on a single node and restarted it,
the session survives (if the DB is still running). This needs to be
tested on all supported containers. Axion was used because it is an
in-VM DB (so imposes no further integration dependencies on the Getting
Started stuff and is useful for unit-testing) and was in use by Geronimo
at the time. So I suggest that any replacement needs to also be able to
run in-vm aswell. As we go further and move WADI's actual configuration
from the app to the container-level, these issues will disappear and
WADI will be able to be hooked to whatever persistance mechanism is
shipped in Geronimo by default.
- Jan & Jeff , you may want to consider pushing some of this session
manager selection code up into a shared GeronimoWebContainer abstraction
so that you don't both end up maintaining similar but diverging code...
- I may have overlooked a couple of issues. If I come across them, I
shall post them.
Further work on Geronimo integration :
- more testing
- make a new WADI release and update geronimo-trunk to use it
- look at applying diffs to a G1.0 tree and producing a binary patch for
1.0 distros.
- update website and release it
Jules
Jules Gosnell wrote:
Guys,
Jan and I have just refactored the Geronimo Jetty and Tomcat
integrations to take the same approach to the installation of a 3rd
party session manager, to ease the integration of WADI. This is now
checked in on Geronimo's trunk.
Each top level web container GBean now supports a pair of attributes -
LocalSessionManager and DistributableSessionManager. These may be used
to override the container's choice of SessionManager for webapps with
and without the <distributable/> tag present in the WEB-INF/web.xml,
respectively.
The attributes expect to be given a classname, if required, this class
will be loaded and instantiated. The resulting instance will be used
as the session manager. If not provided, the container will use a
sensible default. Currently Jetty and TC are set up to use their own
default session managers in the local case and the correct WADI
session manager in the distributable case.
This means that the same WADI-enabled webapp, with its plan held
internally (WEB-INF/geronimo-web.xml) may now be hot-deployed on
either a Jetty or a Tomcat based Geronimo, without changes :-)
I will post specific WADI issues to the WADI dev lists
(wadi-dev@incubator.apache.org, [EMAIL PROTECTED]).
This shouldn't be seen as a final position on the subject - there is
still much to talk about, but is a useful interim step, that allows us
to have something working whilst we figure out how to go forward.
Enjoy,
Jules
--
"Open Source is a self-assembling organism. You dangle a piece of
string into a super-saturated solution and a whole operating-system
crystallises out around it."
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* Jules Gosnell
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* Core Developers Network (Europe)
*
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