On Fri, Jan 27, 2017 at 10:24 PM, Patrick Hemmer <[email protected]> wrote: > Something that might satisfy both requests, why not just append to the > existing request-id? > > unique-id-format %[req.hdr(X-Request-ID)],%{+X}o\ > %ci:%cp_%fi:%fp_%Ts_%rt:%pid > > This does result in a leading comma if X-Request-ID is unset. If that's > unpleasant, you could do something like write tiny LUA sample converter to > append a comma if the value is not empty.
However, just setting the `unique-id-format` is not enough, as we should also send that ID to the backend, thus there is a need of `http-request set-header X-Request-Id %[unique-id] if !...`. (By not using the `http-request`, we do get the ID from the header in the log, but not to the backend.) But now -- I can't say with certainty, but I remember trying various variants -- I think the evaluation order of `unique-id-format` is after all the `http-request` rules, thus the header will always be empty (if not explicitly set in the request), although in the log we would have a correct ID. (This is why I settled with a less optimal solution of having two headers, but with identical values, and working correctly in all instances.) Ciprian.
