[asterisk-bugs] [JIRA] (ASTERISK-26941) ARI WebSocket forcibly closed due to fatal write error on repeated mute/unmute requests

[Colin (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-26941?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=236860#comment-236860 ] 

Colin commented on ASTERISK-26941:
----------------------------------

Thank you. For most events, our app is simply doing a log trace (we only handle talking, DTMF and Statis start/end events). I am however replacing the .Net Task-based dispatcher that handles the events with a Producer/Consumer queue. This will allow the WebSocket read thread to return immediately. The strategies of increasing the timeout, and of not writing Channel Variables seems to stop the disconnection,  so thanks for that.

Just to confirm, when we see the log message " stasis/app.c: Deactivating Stasis app 'voice_2' ", we can't reconnect on the WebSocket connection. Are you saying that we should be able to do this without restarting Asterisk or any of its modules? We're using the .Net WebSockets4Net library, and it may be that there's a problem there...

> ARI WebSocket forcibly closed due to fatal write error on repeated mute/unmute requests
> ---------------------------------------------------------------------------------------
>
>                 Key: ASTERISK-26941
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-26941
>             Project: Asterisk
>          Issue Type: New Feature
>      Security Level: None
>          Components: Resources/res_http_websocket
>    Affects Versions: 14.3.0
>         Environment: Ubuntu 16.04.2 LTS on Windows Azure VM
>            Reporter: Colin
>            Assignee: Colin
>
> We're testing a Stasis conference application and seeing forced WebSocket closes from res_http_websocket.c. Testing with SIPp, we're calling mute/unmute asynchronously  for batches of callers (POST /channels/\{channelId}/mute). 
> We're running with about 60 SIPp connections. Other batch operations (for example move callers between bridges) complete correctly. This issue seems to be specific to mute and unmute commands. 
> Asterisk does not crash, but the Stasis app effectively becomes moribund. We're muting and unmuting callers as one group, using async tasks which we marshal before any further requests are sent to ARI. 
> We set up a test server to get some forensic information, using SIPp to simulate 60 connections. We are finding that about 10-15 successful mute/unmute operations take place from each group, before the WebSocket and HTTP connections become moribund. I can provide a debug log file. Some salient events that we've picked out when we do a group mute/unmute, however, are:
> 1) A large number of webocket writes (in the order of n x n, where n is the number of clients being muted/unmuted), like:
> {noformat}
> [Apr 10 14:36:29] DEBUG[35342] taskprocessor.c: Taskprocessor 'subm:voice_2-00000065' cleared the high water alert.
> [Apr 10 14:36:29] DEBUG[35342] res_http_websocket.c: Writing websocket string of length 668
> [Apr 10 14:36:29] DEBUG[35342] res_http_websocket.c: Writing websocket text frame, length 668
> {noformat}
> 2) After a small number of successful mute/unmute operations, the websocket faults, and closes
> {noformat}
> Apr 10 14:36:30] DEBUG[35342] res_http_websocket.c: Closing WS with 1011 because we can't fulfill a write request
> [Apr 10 14:36:30] DEBUG[35342] utils.c: Timed out trying to write 
> [Apr 10 14:36:30] DEBUG[35342] res_http_websocket.c: WebSocket connection from 'xxx.xxx.xxx.xxx:18133' forcefully closed due to fatal write error 
> {noformat}
> 3) A large number of attempted writes, followed by deactivation of the Stasis application
> {noformat}
> [Apr 10 14:36:30] DEBUG[35342] res_http_websocket.c: Writing websocket text frame, length 668
> [Apr 10 14:36:30] NOTICE[35342] ari/ari_websockets.c: Problem occurred during websocket write to :18133, websocket closed
> [Apr 10 14:36:30] WARNING[35340] ari/ari_websockets.c: WebSocket read error: Software caused connection abort
> [Apr 10 14:36:30] VERBOSE[35340] stasis/app.c: Deactivating Stasis app 'voice_2'
> {noformat}
> We can replicate this at will, and we have extensive verbose/debug logs if these are needed.



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