Getting a Server Error 500 when cancelling a task

[MichaelClerx]

https://scrambler.cs.ox.ac.uk/experiments/tasks

could be that it's already cancelled, everything's very slow just now. Either way, should be a better message (or just an ignore, if what I want is already done)

[jonc125]

I've just got a 504 Gateway Timeout trying to cancel a large number of tasks. The logs show:

Dec 04 09:18:55 scrambler weblab[176643]: Fri Dec  4 09:18:55 2020 - SIGPIPE: writing to a closed pipe/socket/fd (probably the client disconnected) on request /experiments/tasks !!!
Dec 04 09:18:55 scrambler weblab[176643]: Fri Dec  4 09:18:55 2020 - uwsgi_response_write_headers_do(): Broken pipe [core/writer.c line 238] during POST /experiments/tasks
Dec 04 09:18:55 scrambler weblab[176643]: OSError: write error
Dec 04 09:18:55 scrambler weblab[176643]: [pid: 176876|app: 0|req: 53/323] () {54 vars in 1205 bytes} [Fri Dec  4 09:17:45 2020] POST /experiments/tasks => generated 0 bytes in 70404 msecs (HTTP/2.0 302) 5 headers in 0 bytes (1 switches on core 0)

Fixing this might require changing the approach so the form doesn't do a page submission but does a series of AJAX calls to cancel each experiment in turn, adding notifications to the page as they return?