Re: http2 connection keepalive broken
On Mon, Apr 30, 2018 at 12:06 PM, Stefan Eissing
>> Am 30.04.2018 um 12:00 schrieb Yann Ylavic <ylavic.dev@xxxxxxxxx>:
>> There nothing wrong with returning CONN_STATE_WRITE_COMPLETION here
>> like before, CONN_STATE_HANDLER is wrong though.
>> So the previous code with s/CONN_STATE_HANDLER/CONN_STATE_LINGER/
>> should restore the behaviour I think.
> Will give it a try. However, I had already keepalive tests in the http2
> test suite, but those do not fail. So, mpm_event's behaviour on when
> it ditches idle connections is not really clear to me and other tests I
> do not know of.
Do the tests check for e.g. 1s (linger) vs 5s (keepalive) timeout?
> Basically, I am a bit frustrated by mpm_event and its non-documentation.
> Maybe I missed the documents that explain how its different states actually work?
I can try a formal documentation with a bit of my own idle time :)
Meanwhile, this comment in process_socket() is the only one I'm aware of:
* The process_connection hooks above should set the connection state
* appropriately upon return, for event MPM to either:
* - do lingering close (CONN_STATE_LINGER),
* - wait for readability of the next request with respect to the keepalive
* timeout (state CONN_STATE_CHECK_REQUEST_LINE_READABLE),
* - wait for read/write-ability of the underlying socket with respect to
* its timeout by setting c->clogging_input_filters to 1 and the sense
* to CONN_SENSE_WANT_READ/WRITE (state CONN_STATE_WRITE_COMPLETION),
* - keep flushing the output filters stack in nonblocking mode, and then
* if required wait for read/write-ability of the underlying socket with
* respect to its own timeout (state CONN_STATE_WRITE_COMPLETION); since
* completion at some point may require reads (e.g. SSL_ERROR_WANT_READ),
* an output filter can also set the sense to CONN_SENSE_WANT_READ at any
* time for event MPM to do the right thing,
* - suspend the connection (SUSPENDED) such that it now interracts with
* the MPM through suspend/resume_connection() hooks, and/or registered
* poll callbacks (PT_USER), and/or registered timed callbacks triggered
* by timer events.
* If a process_connection hook returns an error or no hook sets the state
* to one of the above expected value, we forcibly close the connection w/
* CONN_STATE_LINGER. This covers the cases where no process_connection
* hook executes (DECLINED), or one returns OK w/o touching the state (i.e.
* CONN_STATE_READ_REQUEST_LINE remains after the call) which can happen
* with third-party modules not updated to work specifically with event MPM
* while this was expected to do lingering close unconditionally with
* worker or prefork MPMs for instance.
We can do better...