Allow optional entry to /ruler/rule_groups endpoint

[AlexDCraig]

What this PR does: Allow optional entry into /ruler/rule_groups endpoint via nginx proxy

Which issue(s) this PR fixes:
Fixes #475

Checklist

• [ x] CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[nschad]

Custom route "injection" is already supported by setting .Values.nginx.config.serverSnippet

I'm inclined to reject this PR on the basis that this would just add more spaghetti templating

[AlexDCraig]

The custom route injection for this is kind of hideous:

nginx:
  config:
    serverSnippet:
      location ~ /ruler/rule_groups {
          proxy_pass      http://{{ template "cortex.fullname" . }}-ruler.{{ printf "%s.svc.%s:%d" .Release.Namespace .Values.clusterDomain (.Values.config.server.http_listen_port | int) }}$request_uri;
      }

Or is there a way to call that $rootDomain function the other routes use from the values file?

[nschad]

The custom route injection for this is kind of hideous:

nginx:
  config:
    serverSnippet:
      location ~ /ruler/rule_groups {
          proxy_pass      http://{{ template "cortex.fullname" . }}-ruler.{{ printf "%s.svc.%s:%d" .Release.Namespace .Values.clusterDomain (.Values.config.server.http_listen_port | int) }}$request_uri;
      }

Or is there a way to call that $rootDomain function the other routes use from the values file?

I don't know, have you tried setting $rootDomain? I assume the context might be different

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 30 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.

[nschad]

To be honest I can't really follow my reasoning before as to why this not worth doing.

We can definitely get this in.

[nschad]

Can we move this under nginx.config? Considering that the docs say it's not part of the ruler api, this should be a bit better suited there. Also might I suggest a rename to something like exposeRulerRulesAPIEndpoint ?

Whatever you choose please no snake_case. You can also add a doc string