feat: define extra app config which generates ConfigMap (#23)

* feat: define extra app config which generates ConfigMap

* change appConfig from multiline string to dict

* docs: document the usage of appConfig key to generate ConfigMap automatically

* chore: load ConfigMap with tplvalues from Bitnami common instead of just toYaml

* tests: appConfig and extraVolumes

* docs: warn about appConfig vs extraAppConfig priority

* docs: reference section with MarkDown link

Co-authored-by: Tom Coufal <7453394+tumido@users.noreply.github.com>

* docs: reference Backstage config docs and template to clarify config priority

* docs: typo

Co-authored-by: Tom Coufal <7453394+tumido@users.noreply.github.com>

* fix: run helm-docs

* fix: do not use specific drivers on CI tests

* chore: bump minor version

Co-authored-by: Tom Coufal <7453394+tumido@users.noreply.github.com>

charts/backstage/Chart.yaml

@@ -15,7 +15,7 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.9.0
+version: 0.10.0
 
 dependencies:
   - name: common

charts/backstage/README.md

@@ -1,7 +1,7 @@
 
 # Backstage Helm Chart
 
-![Version: 0.9.0](https://img.shields.io/badge/Version-0.9.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square)
+![Version: 0.10.0](https://img.shields.io/badge/Version-0.10.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square)
 
 A Helm chart for deploying a Backstage application
 
@@ -85,6 +85,7 @@ The command removes all the Kubernetes components associated with the chart and
 
 | Key | Description | Type | Default |
 |-----|-------------|------|---------|
+| backstage.appConfig | Generates ConfigMap and configures it in the Backstage pods | object | `{}` |
 | backstage.args |  | list | `[]` |
 | backstage.command[0] |  | string | `"node"` |
 | backstage.command[1] |  | string | `"packages/backend"` |
@@ -239,6 +240,21 @@ Now that the ConfigMap has been created on your Kubernetes cluster, you can refe
 
 The chart will mount the content of the ConfigMap as a new `app-config.extra.yaml` file and automatically pass the extra configuration to your instance.
 
+### Pass configuration to be stored in a ConfigMap
+
+> :warning: In case of using both appConfig and extraAppConfig, appConfig will have higher priority over extraAppConfig. For more information you can check the [Backstage docs](https://backstage.io/docs/conf/writing#configuration-files) and how this [Helm Chart configures the Backstage arguments](templates/backstage-deployment.yaml)
+
+In addition to following the [previous step "Pass extra configuration files"](#pass-extra-configuration-files), you can get the Config Map automatically deployed with this Helm Chart by defining the key `appConfig`:
+
+```diff
+  backstage:
++   appConfig:
++     app:
++       baseUrl: https://somedomain.tld
+```
+
+The chart will mount the content of the ConfigMap as a new `app-config-from-configmap.yaml` file and automatically pass the extra configuration to your instance.
+
 ### Configuring Chart PostgreSQL
 
 With the Backstage Helm Chart, it offers - as a subchart - a Bitnami PostgreSQL database. This can be enabled by switching `postgresql.enabled` to true (it is `false` by default). If switched on, the Helm Chart, on deployment, will automatically deploy a PostgreSQL instance and configure it with the credentials you specify. There are multiple ways of doing this that will be detailed below.

charts/backstage/README.md.gotmpl

@@ -170,6 +170,21 @@ Now that the ConfigMap has been created on your Kubernetes cluster, you can refe
 
 The chart will mount the content of the ConfigMap as a new `app-config.extra.yaml` file and automatically pass the extra configuration to your instance.
 
+### Pass configuration to be stored in a ConfigMap
+
+> :warning: In case of using both appConfig and extraAppConfig, appConfig will have higher priority over extraAppConfig. For more information you can check the [Backstage docs](https://backstage.io/docs/conf/writing#configuration-files) and how this [Helm Chart configures the Backstage arguments](templates/backstage-deployment.yaml)
+
+In addition to following the [previous step "Pass extra configuration files"](#pass-extra-configuration-files), you can get the Config Map automatically deployed with this Helm Chart by defining the key `appConfig`:
+
+```diff
+  backstage:
++   appConfig:
++     app:
++       baseUrl: https://somedomain.tld
+```
+
+The chart will mount the content of the ConfigMap as a new `app-config-from-configmap.yaml` file and automatically pass the extra configuration to your instance.
+
 ### Configuring Chart PostgreSQL
 
 With the Backstage Helm Chart, it offers - as a subchart - a Bitnami PostgreSQL database. This can be enabled by switching `postgresql.enabled` to true (it is `false` by default). If switched on, the Helm Chart, on deployment, will automatically deploy a PostgreSQL instance and configure it with the credentials you specify. There are multiple ways of doing this that will be detailed below.

charts/backstage/ci/appConfig-values.yaml

@@ -0,0 +1,10 @@
+backstage:
+  appConfig:
+    app:
+      # Let's test that everything is fine with comments
+      title: The very best Backstage Helm Chart! :D
+      baseUrl: https://somedomain.tl
+    backend:
+      baseUrl: https://somedomain.tl
+      listen:
+        port: 12345

charts/backstage/ci/extraVolumes-values.yaml

@@ -0,0 +1,9 @@
+backstage:
+  extraVolumeMounts:
+    - name: test
+      mountPath: /somepath
+      readOnly: true
+  extraVolumes:
+    - name: test
+      emptyDir:
+        sizeLimit: 5Mi

charts/backstage/templates/app-config-configmap.yaml

@@ -0,0 +1,9 @@
+{{- if .Values.backstage.appConfig }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: backstage-app-config
+data:
+  app-config.yaml: |
+    {{- include "common.tplvalues.render" ( dict "value" .Values.backstage.appConfig "context" $) | nindent 4 }}
+{{- end }}

charts/backstage/templates/backstage-deployment.yaml

@@ -43,6 +43,11 @@ spec:
           {{- include "common.tplvalues.render" ( dict "value" .Values.backstage.extraVolumes "context" $ ) | nindent 8 }}
         {{- end }}
         {{- end }}
+        {{- if .Values.backstage.appConfig }}
+        - name: backstage-app-config
+          configMap:
+            name: backstage-app-config
+        {{- end }}
       {{- if .Values.backstage.image.pullSecrets }}
       imagePullSecrets:
       {{- range .Values.backstage.image.pullSecrets }}
@@ -83,6 +88,10 @@ spec:
             - {{ .filename | quote }}
           {{- end }}
           {{- end }}
+          {{- if .Values.backstage.appConfig }}
+            - "--config"
+            - "app-config-from-configmap.yaml"
+          {{- end }}
           {{- end }}
           {{- if .Values.backstage.extraEnvVarsSecrets }}
           envFrom:
@@ -114,13 +123,18 @@ spec:
             - name: backend
               containerPort: {{ .Values.backstage.containerPorts.backend }}
               protocol: TCP
-          {{- if (or .Values.backstage.extraAppConfig (and .Values.backstage.extraVolumeMounts .Values.backstage.extraVolumes)) }}
+          {{- if (or .Values.backstage.extraAppConfig .Values.backstage.appConfig (and .Values.backstage.extraVolumeMounts .Values.backstage.extraVolumes)) }}
           volumeMounts:
             {{- range .Values.backstage.extraAppConfig }}
             - name: {{ .configMapRef }}
               mountPath: "/app/{{ .filename }}"
               subPath: {{ .filename }}
             {{- end }}
+            {{- if .Values.backstage.appConfig }}
+            - name: backstage-app-config
+              mountPath: /app/app-config-from-configmap.yaml
+              subPath: app-config.yaml
+            {{- end }}
             {{- if .Values.backstage.extraVolumeMounts }}
               {{- include "common.tplvalues.render" ( dict "value" .Values.backstage.extraVolumeMounts "context" $ ) | nindent 12 }}
             {{- end }}

charts/backstage/values.yaml

@@ -143,6 +143,16 @@ backstage:
   ## ref: https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#set-the-security-context-for-a-container
   containerSecurityContext: {}
 
+  # Allows to define the appConfig as a multiline string that generates a ConfigMap
+  # automatically, not requiring to have it pre provisioned as with the extraAppConfig key.
+  # DO NOT USE if you need to put sensitive data in the appConfig.
+  # E.g:
+  # appConfig:
+  #   app:
+  #     baseUrl: https://somedomain.tld
+  # -- Generates ConfigMap and configures it in the Backstage pods
+  appConfig: {}
+
 ## @section Traffic Exposure parameters
 
 ## Service parameters