feat: Metrics for Prometheus (#309)

* feat: prometheus metrics

* Added Prometheus resources support to helm chart

deploy/helm/templates/_helpers.tpl

@@ -107,3 +107,23 @@ Define hostname
   {{- (urlParse (tpl .Values.config.web.external_url .)).hostname -}}
 {{- end -}}
 {{- end -}}
+
+
+{{/*
+wg-portal.util.merge will merge two YAML templates or dict with template and output the result.
+This takes an array of three values:
+- the top context
+- the template name or dict of the overrides (destination)
+- the template name of the base (source)
+{{- include "wg-portal.util.merge" (list $ .Values.podLabels "wg-portal.selectorLabels") }}
+{{- include "wg-portal.util.merge" (list $ "wg-portal.destTemplate" "wg-portal.sourceTemplate") }}
+*/}}
+{{- define "wg-portal.util.merge" -}}
+{{- $top := first . -}}
+{{- $overrides := index . 1 -}}
+{{- $base := fromYaml (include (index . 2) $top) | default (dict) -}}
+{{- if kindIs "string" $overrides -}}
+  {{- $overrides = fromYaml (include $overrides $top) | default (dict) -}}
+{{- end -}}
+{{- toYaml (merge $overrides $base) -}}
+{{- end -}}

deploy/helm/templates/_pod.tpl

@@ -6,11 +6,7 @@ metadata:
     {{- with .Values.podAnnotations }}
     {{- tpl (toYaml .) $ | nindent 4 }}
     {{- end }}
-  labels:
-    {{- include "wg-portal.selectorLabels" . | nindent 4 }}
-    {{- with .Values.podLabels }}
-    {{- toYaml . | nindent 4 }}
-    {{- end }}
+  labels: {{- include "wg-portal.util.merge" (list $ .Values.podLabels "wg-portal.selectorLabels") | nindent 4 }}
 spec:
   {{- with .Values.affinity }}
   affinity: {{- toYaml . | nindent 4 }}
@@ -36,6 +32,9 @@ spec:
       envFrom: {{- tpl (toYaml .) $ | nindent 8 }}
       {{- end }}
       ports:
+        - name: metrics
+          containerPort: {{ .Values.service.metrics.port}}
+          protocol: TCP
         - name: web
           containerPort: {{ .Values.service.web.port }}
           protocol: TCP

deploy/helm/templates/monitoring.yaml

@@ -0,0 +1,41 @@
+{{- with .Values.monitoring -}}
+{{- if and .enabled ($.Capabilities.APIVersions.Has .apiVersion) -}}
+{{- $endpointsKey := (eq .kind "PodMonitor") | ternary "podMetricsEndpoints" "endpoints" -}}
+apiVersion: {{ .apiVersion }}
+kind: {{ .kind }}
+metadata:
+  {{- with .annotations }}
+  annotations: {{- toYaml . | nindent 4 }}
+  {{- end }}
+  labels: {{- include "wg-portal.util.merge" (list $ .labels "wg-portal.labels") | nindent 4 }}
+  name: {{ include "wg-portal.fullname" $ }}
+spec:
+  namespaceSelector:
+    matchNames:
+      - {{ $.Release.Namespace }}
+  selector:
+    matchLabels:
+      {{- include "wg-portal.selectorLabels" $ | nindent 6 }}
+  {{ $endpointsKey }}:
+    - port: metrics
+      path: /metrics
+      {{- with .interval }}
+      interval: {{ . }}
+      {{- end }}
+      {{- with .metricRelabelings }}
+      metricRelabelings: {{- toYaml . | nindent 8 }}
+      {{- end }}
+      {{- with .relabelings }}
+      relabelings: {{- toYaml . | nindent 8 }}
+      {{- end }}
+      {{- with .scrapeTimeout }}
+      scrapeTimeout: {{ . }}
+      {{- end }}
+  {{- with .jobLabel }}
+  jobLabel: {{ . }}
+  {{- end }}
+  {{- with .podTargetLabels }}
+  podTargetLabels: {{- toYaml . | nindent 2 }}
+  {{- end }}
+{{- end -}}
+{{- end -}}

deploy/helm/templates/secret.yaml

@@ -27,9 +27,12 @@ stringData:
     mail: {{- tpl (toYaml .) $ | nindent 6 }}
     {{- end }}
 
-    {{- with .Values.config.statistics }}
-    statistics: {{- tpl (toYaml .) $ | nindent 6 }}
-    {{- end }}
+    statistics:
+      listening_address: :{{ .Values.service.metrics.port }}
+      {{- with .Values.config.statistics }}
+      {{- tpl (toYaml (omit . "listening_address")) $ | nindent 6 }}
+      {{- end }}
+
     web:
       listening_address: :{{ .Values.service.web.port }}
       {{- with .Values.config.web }}

deploy/helm/templates/service.yaml

@@ -12,3 +12,9 @@
 ---
 {{ include "wg-portal.service.tpl" (dict "context" . "scope" .Values.service.wireguard "ports" $ports "name" "wireguard") }}
 {{- end -}}
+
+{{- if and .Values.monitoring.enabled (eq .Values.monitoring.kind "ServiceMonitor") }}
+---
+{{- $portsMetrics := list (dict "name" "metrics" "port" .Values.service.metrics.port "protocol" "TCP" "targetPort" "metrics") -}}
+{{- include "wg-portal.service.tpl" (dict "context" . "scope" .Values.service.metrics "ports" $portsWeb "name" "metrics") }}
+{{- end -}}