Maxim Dounin Wrote: ------------------------------------------------------- > Hello! > > On Fri, Feb 05, 2021 at 03:38:16PM -0500, MarioIshac wrote: > > > Hello all, > > > > I have this example nginx.conf: > > https://gist.github.com/MarioIshac/e6971ab0b343da210de62ebb1c6e2f99 > to > > reproduce the behavior. > > > > I start nginx and an example upstream with: > > > > python3 -u -m http.server 8001 > app.log 2>&1 & sudo nginx > > nginx.log 2>&1 > > > > Upon hitting nginx with `curl -i localhost:8000`, I see these > response > > headers: > > > > X-Trip-Time: 0.001 > > X-Addr: 127.0.0.1:8001 > > X-Status: 200 > > X-Process-Time: - > > > > `cat app.log` shows that upstream was hit successfully, and `cat > nginx.log` > > shows that nginx knows the $upstream_response_time at log time, as I > get > > this log: > > > > 127.0.0.1:8001 200 0.004 > > > > Why does nginx substitute the request time and relevant response > metadata > > (like $upstream_status) at add_header time successfully, yet > substitutes the > > upstream response time with a dash? > > > > My goal with returning $upstream_response_time in a header is so the > client > > can know how much of their request latency was due to their upload > speeds > > vs. server processing time. > > That's because response headers are sent before the > $upstream_response_time is known: it is only known when the > response is fully received from the upstream server, including the > response body, and this happens after the response headers are > sent to the client. If you want to return something in the > response headers, consider the $upstream_header_time variable > instead (http://nginx.org/r/$upstream_header_time). > > -- > Maxim Dounin > http://mdounin.ru/ > _______________________________________________ > nginx mailing list > nginx@nginx.org > http://mailman.nginx.org/mailman/listinfo/nginx
Thanks for the great clarification. I've tested out returning $upstream_header_time in a response header and it is very close to the $upstream_response_time that is logged, so I'll be going with this. This is more out of curiosity rather than a need (since the times were really close anyways), but does nginx have an option to buffer the whole response (headers and body) before sending it? Posted at Nginx Forum: https://forum.nginx.org/read.php?2,290674,290679#msg-290679 _______________________________________________ nginx mailing list nginx@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx
