websockets fail to start after quick restart

[ejurgensen]

For testing, I have a script that kills and immediately restarts forked-daapd. I have noticed that sometimes it fails to start. It seems related to libwebsockets:

[2018-12-09 00:33:24] [DEBUG]      web: LWS Initial logging level 31
[2018-12-09 00:33:24] [DEBUG]      web: LWS Libwebsockets version: 2.0.3 unknown-build-hash
[2018-12-09 00:33:24] [DEBUG]      web: LWS IPV6 not compiled in
[2018-12-09 00:33:24] [DEBUG]      web: LWS libev support compiled in but disabled
[2018-12-09 00:33:24] [DEBUG]      web: LWS libuv support compiled in but disabled
[2018-12-09 00:33:24] [DEBUG]      web: LWS  Threads: 1 each 1024 fds
[2018-12-09 00:33:24] [DEBUG]      web: LWS  mem: platform fd map:  8192 bytes
[2018-12-09 00:33:24] [DEBUG]      web: LWS  Compiled with OpenSSL support
[2018-12-09 00:33:24] [DEBUG]      web: LWS  SSL disabled: no LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT
[2018-12-09 00:33:24] [DEBUG]      web: LWS Creating Vhost 'default' port 3688, 2 protocols
[2018-12-09 00:33:24] [  LOG]      web: LWS ERROR on binding fd 49 to port 3688 (-1 98)
[2018-12-09 00:33:24] [  LOG]      web: LWS Failed to create default vhost
[2018-12-09 00:33:24] [  LOG]      web: Failed to create websocket context
[2018-12-09 00:33:24] [FATAL]    httpd: Websocket init failed

This is with Ubuntu 16.04.

@chme can you see if there is anything to do about it?

[chme]

Looks like the port is not immediately available after killing forked-daapd. I am not able to reproduce it on my notebook running solus as distribution (even with open connections to the websocket, killing and restarting works fine). I have no clue what can be done about that ... and did not find anything helpful searching the web.

[ejurgensen]

Thanks for looking into it. I was hoping there might be some libwebsocket option to fix it, maybe something that makes it use SO_REUSEADDR when it tries to bind to the port.