Feature flag to enable/disable canary + optional prometheus install (#937)

charts/fission-core/templates/_helpers.tpl

@@ -14,3 +14,18 @@ We truncate at 24 chars because some Kubernetes name fields are limited to this
 {{- $name := default .Chart.Name .Values.nameOverride -}}
 {{- printf "%s-%s" .Release.Name $name | trunc 24 | trimSuffix "-" -}}
 {{- end -}}
+
+{{/*
+This is a template with config parameters for optional features in fission. This gets mounted on to the controller pod
+as a config map.
+To add new features with config parameters, create a yaml block below with the feature name and define a corresponding struct in
+controller/config.go
+*/}}
+{{- define "config" -}}
+canary:
+  enabled: {{ .Values.canaryDeployment.enabled }}
+  {{- if .Values.prometheusDeploy }}
+  prometheusSvc: "http://{{ .Release.Name }}-prometheus-server.{{ .Release.Namespace }}"
+  {{- end }}
+  {{- printf "\n" -}}
+{{- end -}}

charts/fission-core/templates/deployment.yaml

@@ -103,6 +103,15 @@ metadata:
   name: fission-builder
   namespace: {{ .Values.builderNamespace }}
 
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: feature-config
+  namespace: {{ .Release.Namespace }}
+data:
+  "config.yaml": {{ include "config" . | b64enc }}
+
 ---
 apiVersion: extensions/v1beta1
 kind: Deployment
@@ -144,7 +153,15 @@ spec:
             port: 8888
           initialDelaySeconds: 35
           periodSeconds: 5
+        volumeMounts:
+        - name: config-volume
+          mountPath: /etc/config/config.yaml
+          subPath: config.yaml
       serviceAccount: fission-svc
+      volumes:
+      - name: config-volume
+        configMap:
+          name: feature-config
 
 ---
 apiVersion: extensions/v1beta1