Log the request time in nginx container logs

[seanhamlin]

It can be useful to log the request time in the nginx container log, as the container logs also log the pod name, and hostname. So you could in theory create a visualisation to plot response times for a particular path, by kubernetes host or pod name. This could be useful for performance reasons.

See https://github.com/uselagoon/lagoon-images/blob/main/images/nginx/nginx.conf#L19

There is a variable we can use for this (see the documentation)

$request_time
request processing time in seconds with a milliseconds resolution; time elapsed between the first bytes were read from the client and the log write after the last bytes were sent to the client

[smlx]

This would need an associated update to the regex for parsing nginx container logs.

Because there would be a period where some nginx logs would have the $request_time and some wouldn't it would need to be put somewhere unambiguous for regex parsing.

Probably this makes sense:

-$status $body_bytes_sent "$http_referer"
+$status $body_bytes_sent $request_time "$http_referer"

Because then it is an optional bare number before the quoted referer which can be parsed like:

-(?<code>[^ ]*) (?<size>[^ ]*) "
+(?<code>[^ ]*) (?<size>[^ ]*)(?: (?<request_time>[^ ]*))? "