implement secret mounting (#41)

Adds the ability for people to mount secrets. This can be used for referencing certificates in the config, like so:

secretMounts:
- name: jaeger-cert
  secretName: jaeger-cert
  mountPath: /etc/tls
  readOnly: true
  subPath: jaeger # subPath is optional
exporters:
    jaeger:
      endpoint: localhost
      cert_file: /etc/tls/tls.crt
      key_file: /etc/tls/tls.key

charts/opentelemetry-collector/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v2
 name: opentelemetry-collector
-version: 0.5.1
+version: 0.5.2
 description: OpenTelemetry Collector Helm chart for Kubernetes
 type: application
 home: https://opentelemetry.io/

charts/opentelemetry-collector/templates/_pod.tpl

@@ -61,6 +61,14 @@ containers:
         mountPropagation: {{ .mountPropagation }}
         {{- end }}
       {{- end }}
+      {{- range .Values.secretMounts }}
+      - name: {{ .name }}
+        mountPath: {{ .mountPath }}
+        readOnly: {{ .readOnly }}
+        {{- if .subPath }}
+        subPath: {{ .subPath }}
+        {{- end }}
+      {{- end }}
       {{- if and $.isAgent .Values.agentCollector.containerLogs.enabled }}
       - name: varlogpods
         mountPath: /var/log/pods
@@ -81,6 +89,11 @@ volumes:
     hostPath:
       path: {{ .hostPath }}
   {{- end }}
+  {{- range .Values.secretMounts }}
+  - name: {{ .name }}
+    secret:
+      secretName: {{ .secretName }}
+  {{- end }}
   {{- if and $.isAgent .Values.agentCollector.containerLogs.enabled }}
   - name: varlogpods
     hostPath:

charts/opentelemetry-collector/values.yaml

@@ -101,6 +101,7 @@ affinity: {}
 
 extraEnvs: []
 extraHostPathMounts: []
+secretMounts: []
 
 # Configuration for ports, shared between agentCollector, standaloneCollector and service.
 # Can be overridden here or for agentCollector and standaloneCollector independently.