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] > <mailto:[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] > <mailto:[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] >>> <mailto:[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] >>> <mailto:[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] >>>>> <mailto:[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] >>>>> <mailto:[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] >>>>>> <mailto:[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] >>>>>>> <mailto:[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 >>>>>>> <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 >>>>>> >>>>>> >>>> >> >
