Hey guys, just a quick note to bring back the conversation on track to the 0.24-RC1 release. Is my understanding correct that there are currently no binding -1's?
@Vinod: what do you think, are we good to release? Thanks! *Marco Massenzio* *Distributed Systems Engineerhttp://codetrips.com <http://codetrips.com>* On Tue, Sep 1, 2015 at 1:49 AM, Dario Rexin <[email protected]> wrote: > One more question. From the Mesos code it doesn’t look like events are > being split or combined, so given I have a client that gives me access to > the individual chunks, is it safe to assume that each chunk contains > exactly one event? Because that would make parsing the events a lot easier > for me. > > Thanks, > Dario > > On Sep 1, 2015, at 8:42 AM, [email protected] wrote: > > Hi Vinod, > > thanks for the explanation, I got it now. > > Thanks, > Dario > > On 31.08.2015, at 23:47, Vinod Kone <[email protected]> wrote: > > I think you might be confused with the HTTP chunked encoding and RecordIO > encoding. Most HTTP client libraries dechunk the stream before presenting > it to the application. So the application needs to know the encoding of the > dechunked data to be able to process it. > > In Mesos's case, the server (master here) can encode it in JSON or > Protobuf. We wanted to have a consistent way to encode both these formats > and Record-IO format was the one we settled on. Note that this format is > also used by the Twitter streaming API > <https://dev.twitter.com/streaming/overview/processing> (see delimited > messages section). > > HTH, > > On Mon, Aug 31, 2015 at 2:09 PM, Dario Rexin <[email protected]> wrote: > >> Hi Vino, >> >> On Aug 31, 2015, at 9:36 PM, Vinod Kone <[email protected]> wrote: >> >> Hi Dario, >> >> Can you test with "curl --no-buffer" option? Looks like your stdout might >> be line-buffered. >> >> >> that did the trick, thanks! >> >> >> The reason we used record-io formatting is to be consistent in how we >> stream protobuf and json encoded data. >> >> >> How does simple chunked encoding prevent you from doing this? >> >> Thanks, >> Dario >> >> On Fri, Aug 28, 2015 at 2:04 PM, <[email protected]> wrote: >> >>> Anand, >>> >>> thanks for the explanation. I didn't think about the case when you have >>> to split a message, now it makes sense. >>> >>> But the case I observed with curl is still weird. Even when splitting a >>> message, it should still receive both parts almost at the same time. Do you >>> have any idea why it could behave like this? >>> >>> On 28.08.2015, at 21:31, Anand Mazumdar <[email protected]> wrote: >>> >>> Dario, >>> >>> Most HTTP libraries/parsers ( including one that Mesos uses internally ) >>> provide a way to specify a default size of each chunk. If a Mesos Event is >>> too big , it would get split into smaller chunks and vice-versa. >>> >>> -anand >>> >>> On Aug 28, 2015, at 11:51 AM, [email protected] wrote: >>> >>> Anand, >>> >>> in the example from my first mail you can see that curl prints the size >>> of a message and then waits for the next message and only when it receives >>> that message it will print the prior message plus the size of the next >>> message, but not the actual message. >>> >>> What's the benefit of encoding multiple messages in a single chunk? You >>> could simply create a single chunk per event. >>> >>> Cheers, >>> Dario >>> >>> On 28.08.2015, at 19:43, Anand Mazumdar <[email protected]> wrote: >>> >>> Dario, >>> >>> Can you shed a bit more light on what you still find puzzling about the >>> CURL behavior after my explanation ? >>> >>> PS: A single HTTP chunk can have 0 or more Mesos (Scheduler API) Events. >>> So in your example, the first chunk had complete information about the >>> first “event”, followed by partial information about the subsequent event >>> from another chunk. >>> >>> As for the benefit of using RecordIO format here, how else do you think >>> we could have de-marcated two events in the response ? >>> >>> -anand >>> >>> >>> On Aug 28, 2015, at 10:01 AM, [email protected] wrote: >>> >>> Anand, >>> >>> thanks for the explanation. I'm still a little puzzled why curl behaves >>> so strange. I will check how other client behave as soon as I have a chance. >>> >>> Vinod, >>> >>> what exactly is the benefit of using recordio here? Doesn't it make the >>> content-type somewhat wrong? If I send 'Accept: application/json' and >>> receive 'Content-Type: application/json', I actually expect to receive only >>> json in the message. >>> >>> Thanks, >>> Dario >>> >>> On 28.08.2015, at 18:13, Vinod Kone <[email protected]> wrote: >>> >>> I'm happy to add the "\n" after the event (note it's different from >>> chunk) if that makes CURL play nicer. I'm not sure about the "\r" part >>> though? Is that a nice to have or does it have some other benefit? >>> >>> The design doc is not set in the stone since this has not been released >>> yet. So definitely want to do the right/easy thing. >>> >>> On Fri, Aug 28, 2015 at 7:53 AM, Anand Mazumdar <[email protected]> >>> wrote: >>> >>>> Dario, >>>> >>>> Thanks for the detailed explanation and for trying out the new API. >>>> However, this is not a bug. The output from CURL is the encoding used by >>>> Mesos for the events stream. From the user doc >>>> <https://github.com/apache/mesos/blob/master/docs/scheduler_http_api.md> >>>> : >>>> >>>> *"Master encodes each Event in RecordIO format, i.e., string >>>> representation of length of the event in bytes followed by JSON or binary >>>> Protobuf (possibly compressed) encoded event. Note that the value of >>>> length will never be ‘0’ and the size of the length will be the size of >>>> unsigned integer (i.e., 64 bits). Also, note that the RecordIO encoding >>>> should be decoded by the scheduler whereas the underlying HTTP chunked >>>> encoding is typically invisible at the application (scheduler) layer.“* >>>> >>>> If you run CURL with tracing enabled i.e. —trace, the output would be >>>> something similar to this: >>>> >>>> <= Recv header, 2 bytes (0x2) >>>> 0000: 0d 0a .. >>>> <= Recv data, 115 bytes (0x73) >>>> 0000: 36 64 0d 0a 31 30 35 0a 7b 22 73 75 62 73 63 72 6d..105.{"subscr >>>> 0010: 69 62 65 64 22 3a 7b 22 66 72 61 6d 65 77 6f 72 ibed":{"framewor >>>> 0020: 6b 5f 69 64 22 3a 7b 22 76 61 6c 75 65 22 3a 22 k_id":{"value":" >>>> 0030: 32 30 31 35 30 38 32 35 2d 31 30 33 30 31 38 2d 20150825-103018- >>>> 0040: 33 38 36 33 38 37 31 34 39 38 2d 35 30 35 30 2d 3863871498-5050- >>>> 0050: 31 31 38 35 2d 30 30 31 30 22 7d 7d 2c 22 74 79 1185-0010"}},"ty >>>> 0060: 70 65 22 3a 22 53 55 42 53 43 52 49 42 45 44 22 pe":"SUBSCRIBED" >>>> 0070: 7d 0d 0a }.. >>>> <others >>>> >>>> In the output above, the chunks are correctly delimited by ‘CRLF' (0d >>>> 0a) as per the HTTP RFC. As mentioned earlier, the output that you observe >>>> on stdout with CURL is of the Record-IO encoding used for the events stream >>>> ( and is not related to the RFC ): >>>> >>>> event = event-size LF >>>> event-data >>>> >>>> Looking forward to more bug reports as you try out the new API ! >>>> >>>> -anand >>>> >>>> On Aug 28, 2015, at 12:56 AM, Dario Rexin <[email protected]> wrote: >>>> >>>> -1 (non-binding) >>>> >>>> I found a breaking bug in the new HTTP API. The messages do not conform >>>> to the HTTP standard for chunked transfer encoding. in RFC 2616 Sec. 3 ( >>>> http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html) a chunk is >>>> defined as: >>>> >>>> chunk = chunk-size [ chunk-extension ] CRLF >>>> chunk-data CRLF >>>> >>>> >>>> The HTTP API currently sends a chunk as: >>>> >>>> chunk = chunk-size LF >>>> chunk-data >>>> >>>> >>>> A standard conform HTTP client like curl can’t correctly interpret the >>>> data as a complete chunk. In curl it currently looks like this: >>>> >>>> 104 >>>> >>>> {"subscribed":{"framework_id":{"value":"20150820-114552-16777343-5050-43704-0000"}},"type":"SUBSCRIBED"}20 >>>> {"type":"HEARTBEAT”}666 >>>> …. waiting … >>>> >>>> {"offers":{"offers":[{"agent_id":{"value":"20150820-114552-16777343-5050-43704-S0"},"framework_id":{"value":"20150820-114552-16777343-5050-43704-0000"},"hostname":"localhost","id":{"value":"20150820-114552-16777343-5050-43704-O0"},"resources":[{"name":"cpus","role":"*","scalar":{"value":8},"type":"SCALAR"},{"name":"mem","role":"*","scalar":{"value":15360},"type":"SCALAR"},{"name":"disk","role":"*","scalar":{"value":2965448},"type":"SCALAR"},{"name":"ports","ranges":{"range":[{"begin":31000,"end":32000}]},"role":"*","type":"RANGES"}],"url":{"address":{"hostname":"localhost","ip":"127.0.0.1","port":5051},"path":"\/slave(1)","scheme":"http"}}]},"type":"OFFERS”}20 >>>> … waiting … >>>> {"type":"HEARTBEAT”}20 >>>> … waiting … >>>> >>>> It will receive a couple of messages after successful registration with >>>> the master and the last thing printed is a number (in this case 666). Then >>>> after some time it will print the first offers message followed by the >>>> number 20. The explanation for this behavior is, that curl can’t interpret >>>> the data it gets from Mesos as a complete chunk and waits for the missing >>>> data. So it prints what it thinks is a chunk (a message followed by the >>>> size of the next messsage) and keeps the rest of the message until another >>>> message arrives and so on. The fix for this is to terminate both lines, the >>>> message size and the message data, with CRLF. >>>> >>>> Cheers, >>>> Dario >>>> >>>> >>>> >>> >>> >>> >> >> > >
