feat(stable/prometheus-mysql-exporter): store MySQL password in a k8s Secret (#14712)

The DATA_SOURCE_NAME environment variable contains a secret key for
authenticating to th MySQL instance (.Values.mysql.pass). This secret
should be stored in a K8s Secret object rather than directly on the
Deployment. Kubernetes RBAC requires more elevated permissions for
viewing Secret data than for viewing Deployment configuration.

Signed-off-by: Thomas Lovett <tklovett@gmail.com>

stable/prometheus-mysql-exporter/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v1
 description: A Helm chart for prometheus mysql exporter with cloudsqlproxy
 name: prometheus-mysql-exporter
-version: 0.3.4
+version: 0.4.0
 home: https://github.com/prometheus/mysqld_exporter
 appVersion: v0.11.0
 sources:

stable/prometheus-mysql-exporter/templates/deployment.yaml

@@ -48,9 +48,9 @@ spec:
 {{- end }}
           ]
 {{- end }}
-          env:
-            - name: DATA_SOURCE_NAME
-              value: "{{ .Values.mysql.user }}:{{ .Values.mysql.pass }}@{{ if .Values.mysql.protocol }}{{ .Values.mysql.protocol }}{{ end }}({{ .Values.mysql.host }}:{{ .Values.mysql.port }})/{{ if .Values.mysql.db }}{{ .Values.mysql.db }}{{ end }}{{ if .Values.mysql.param }}?{{ .Values.mysql.param }}{{ end }}"
+          envFrom:
+            - secretRef:
+                name: {{ template "prometheus-mysql-exporter.fullname" . }}
           ports:
             - containerPort: {{ .Values.service.internalPort }}
           livenessProbe:

stable/prometheus-mysql-exporter/templates/secret-env.yaml

@@ -0,0 +1,7 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: {{ template "prometheus-mysql-exporter.fullname" . }}
+type: Opaque
+stringData:
+  DATA_SOURCE_NAME: "{{ .Values.mysql.user }}:{{ .Values.mysql.pass }}@{{ if .Values.mysql.protocol }}{{ .Values.mysql.protocol }}{{ end }}({{ .Values.mysql.host }}:{{ .Values.mysql.port }})/{{ if .Values.mysql.db }}{{ .Values.mysql.db }}{{ end }}{{ if .Values.mysql.param }}?{{ .Values.mysql.param }}{{ end }}"