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 <dario.re...@me.com> 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
