How to pass $request_id to my application?

[txigreman]

Hi,

I'm trying to make my application aware of the new variable $request_id, so I can use it in the logs and improve traceability.
I've tried to pass it in the enviroment section of the application, but njs templates does not seem to work there.

How could I achieve it?

Thanks in advance.

[ac000]

See here for where and how these variables can be used.

[txigreman]

Thanks for your answer.

I read it before asking, and now I've read it again, but I still doesn't know how to achieve it. Any advice will be welcome.

[lcrilly]

I don't think it is possible to pass $request_id to an application without using rewrite to somehow embed it in the URI. You probably don't want to do that! :)

The conventional approach would be to decorate the request with a new Request-ID: $request_id header. Unit cannot do this and I cannot find a GitHub issue about it.

[txigreman]

Hi Icrilly,

I tried to pass $request_id in a custom header, as I was doing in Nginx, but I didn't find a proper way to achieve it.

Yesterday, I found this issue that you just renamed from "Support for request headers". Being able to set custom request headers would help to pass $request_id to the app, and other headers like X-Forwarded-Prefix, not mentioned in that issue.

In the same issue tippexs suggested to use environment variables as a workaround, that's why I tried to use them, but it only works for static values.

At this point, my idea was to add my use case to that issue, in support of adding the request headers feature; but now that is renamed I think it makes no sense.

Should I open a new issue? What do you think would be the best way to comunicate $request_id variable to the app? What makes more sense for me it's a custom header.

[lcrilly]

Please do create a new issue for the generic need. I was busy cleaning up to make space for it :)

[phpclub]

Variables not work in applications/*/environment section

"applications": {
    "php": {
      "environment": {
        "HTTP_X_REQUEST_ID": "$request_id",
        "MY_URI": "$uri"
      },

in PHP show as text

HTTP_X_REQUEST_ID $request_id
MY_URI $uri