It'd be good to be able to have some sort of support to be able to set headers with the outgoing webhooks.
Use cases would be setting api tokens.
eg. api gateway wants x-api-key
Somewhat related https://github.com/prometheus/alertmanager/issues/324
We don't allow specifying arbitrary headers for HTTP calls anywhere else in Prometheus, but it would probably be fair to add the same HTTP client options that we use elsewhere: TLS options (including client certs), bearer token auth, and basic auth.
Yes, we should have the usual auth options.
Headers should not be supported for the same reasons we don't support url parameters.
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We don't allow specifying arbitrary headers for HTTP calls anywhere else in Prometheus, but it would probably be fair to add the same HTTP client options that we use elsewhere: TLS options (including client certs), bearer token auth, and basic auth.