Hi all, I am working on Varnishkafka (https://github.com/wikimedia/varnishkafka), happily supporting Varnish 4 and its new VSL API. Varnishkafka allows a user to insert the Start SLT_Timestamp or the Resp one into a logline, formatted following a custom strftime string, and only recently I got some reports of logs showing an empty value instead of the Resp timestamp. After a bit of research, I discovered that some particular requests (mostly long tar.gz downloads or Websocket Upgrade request) were missing the Resp timestamp and showing the following lines (grabbed from varnishlog):
- VSL timeout - End synth I discovered from https://www.varnish-cache.org/docs/trunk/reference/vsl.html that the VSL tag is related to error/warnings using the VSL api, but nothing specific so I tried to dig a bit more into the code: - https://github.com/varnishcache/varnish-cache/blob/4.1/lib/libvarnishapi/vsl_arg.c#L350 - https://github.com/varnishcache/varnish-cache/blob/4.1/include/vapi/vapi_options.h#L80 - https://github.com/varnishcache/varnish-cache/blob/4.1/lib/libvarnishapi/vsl.c#L103 - https://github.com/varnishcache/varnish-cache/blob/4.1/lib/libvarnishapi/vsl_dispatch.c#L1342 I tried to simulate a backend fetch timeout with Varnish + Apache + PHP-FPM running a simple script sleeping for minutes, but I wasn't able to reproduce the VSL timeout (120 seconds by default as far as I understand). I am probably missing something trivial but I don't really know how to clearly identify where the issue comes from. My plan would be to add the "-T" parameter support to Varnishkafka but I'd prefer to have some explanation about what a VSL timeout is before proceeding. Thanks a lot in advance! Regards, Luca
_______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
