Arbitrary HTTP Headers in http_config (to authenticate with Cloudflare Access)

[Galvin Gao]

Hi there!

I'm currently try to integrate the `amtool` (github.com/prometheus/alertmanager/cmd/amtool@latest) with my Cloudflare Access protected endpoint. However, Cloudflare Access requires 2 arbitrary headers to set in the request in order to do programmatic authentications, specifically `CF-Access-Client-Id` and `CF-Access-Client-Secret`, and it seems that there's currently no way to specify such arbitrary header information within the http_config field of the configuration. Is there any other ways to do that?

Things I could think of are to try having a HTTP Proxy setup and make the alertmanager pass through that proxy, but it does not seems to be a good idea since it's just another place where things could go wrong, especially we are dealing with alertmanager.

Any help would be greatly appreciated! Thanks a lot!

Best,

Galvin