> When it comes to header manipulations (including method, status etc) > they are already logged so a VUT can already pick that up and save > some work from the VMOD.
It doesn't need to just view the headers; it needs to add headers to encode the active span context. See http://opentracing.io/documentation/pages/api/cross-process-tracing.html And the active span needs to be started before those headers can be added. > I'm not familiar with OT but what I described is how Zipnish does its > tracing. Except that Zipnish relies on the X-Varnish header to get a > unique-ish id, so no blocking call needs to be made. So maybe they are > highly different systems, I chimed in because I saw a Zipkin example > while briefly skimming through the docs. Zipkin is a distributed tracing system that provides OpenTracing implementations, but Zipnish is just using it as a monitor for varnish. It's not doing context propagation. If you're only interested in monitoring varnish, that's fine; but if you want to see how a request is processed in an entire distributed system (i.e. not just varnish, but the backend servers it's sitting in front of or any other service that might be in front of varnish), then you need to do context propagation. _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
