Make Flow ID header configurable
wndhydrnt opened this issue · 3 comments
Is your feature request related to a problem? Please describe.
The company I'm working for uses a different header for flow logs, for historical reasons.
The field flow-id in the access logs of skipper is always empty due to this.
Being able to link access logs with other data through the ID would be helpful while analyzing requests.
Describe the solution you would like
Ideally, it is possible to set the header via a flag passed to the skipper binary on startup. Something like --flow-id-header.
Describe alternatives you've considered (optional)
Change the internal tooling to use the X-Flow-Id header instead. That would be a huge effort that currently seems not worth it.
Additional context (optional)
N/A
Would you like to work on it?
Yes.
Could start in CW 19.
As a workaround you may try adding default filters like so:
-default-filters-prepend='copyRequestHeader("X-Flux-Id", "X-Flow-Id") -> dropHeader("X-Flux-Id")'
-default-filters-append='copyRequestHeader("X-Flow-Id", "X-Flux-Id") -> dropHeader("X-Flow-Id")'
Tested the workaround today. It correctly sets the new header, X-Flux-Id, but the field flow-id in the access logs stays empty.
My guess is that this happens because the write of the access log is deferred here and therefore happens after all filters have been processed already.
While looking into this, I noticed that it is possible to add custom fields to the access log through a filter via the AccessLogAdditionalDataKey of the state bag. A custom filter can set its own value of the field flow-id, which is an acceptable workaround for this issue.
Closing the issue for now.
@wndhydrnt Thank your for the feedback. I think you are right regarding access logs, you may try default-filters-append without dropHeader("X-Flow-Id")' with a caveat that backend will see X-Flow-Id header which might be not a big deal really.