[oauth-proxy]: enable metrics (#7614)

This should allow us to alert on failing authentications

global/oauth-proxy/ci/test-values.yaml

@@ -1,2 +1,5 @@
 global:
   region: "global"
+  tld: "example.com"
+ingress:
+  host_name: "auth"

global/oauth-proxy/templates/deployment.yaml

@@ -17,6 +17,10 @@ spec:
         app: oauth2-proxy
         alert-tier: auth
         alert-service: oauth-proxy
+      {{- with .Values.podAnnotations }}
+      annotations:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
     spec:
       containers:
         - args:
@@ -35,7 +39,9 @@ spec:
             - --cookie-domain={{ .Values.oauth_proxy.cookie_domain }}
             - --cookie-expire={{ .Values.oauth_proxy.cookie_expire }}
             - --oidc-email-claim=email
-
+            {{- with .Values.oauth_proxy.metrics_address }}
+            - --metrics-address={{ . }}
+            {{- end }}
           # Register a new application
           # https://github.com/settings/applications/new
           env:
@@ -63,7 +69,11 @@ spec:
           ports:
             - containerPort: 4180
               protocol: TCP
-
+            {{- if .Values.oauth_proxy.metrics_address }}
+            - containerPort: {{ regexFind `:\d+` .Values.oauth_proxy.metrics_address  | trimPrefix ":" }}
+              protocol: TCP
+              name: metrics
+            {{- end }}
           livenessProbe:
             httpGet:
               path: /ping

global/oauth-proxy/values.yaml

@@ -17,8 +17,11 @@ owner-info:
     - Arturo Reuschenbach
     - Andreas Pfau
     - Hoda Noori
-
+podAnnotations:
+  prometheus.io/scrape: "true"
+  prometheus.io/targets: "kubernetes"
 oauth_proxy:
+  metrics_address: ":9100"
   client_id: DEFINED_IN_VALUES_FILE
   client_secret: DEFINED_IN_VALUES_FILE
   cookie_secret: DEFINED_IN_VALUES_FILE