[WIP] POC PR for merging extra* fields

[rm3l]

Description of the change

This is a draft POC PR to illustrate the proposal in #269

Existing or Associated Issue(s)

Fixes #269

Additional Information

• This branch in our derived chart illustrates how we would define these extra env vars as a map in the default values.yaml file, so that users can easily provide their own values.yaml extending these env vars.
  When using the changes here against this branch, the Deployment rendered contains the expected extra env vars merged from both values.yaml:

helm template

$ helm template charts/backstage --values charts/backstage/ci/test-merge-extraEnvVars-values.yaml

---
[...]
---
# Source: backstage/charts/upstream/templates/backstage-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: release-name-developer-hub
  namespace: "my-ns"
  labels: 
    app.kubernetes.io/name: developer-hub
    helm.sh/chart: upstream-2.5.3
    app.kubernetes.io/instance: release-name
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: backstage
  annotations:
spec:
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app.kubernetes.io/name: developer-hub
      app.kubernetes.io/instance: release-name
      app.kubernetes.io/component: backstage
  template:
    metadata:
      labels:
        app.kubernetes.io/name: developer-hub
        helm.sh/chart: upstream-2.5.3
        app.kubernetes.io/instance: release-name
        app.kubernetes.io/managed-by: Helm
        app.kubernetes.io/component: backstage
      annotations:
        checksum/app-config: a51552987cdb96e1fb3edccca2150e003a888839c9ff5894826e4771b17fdd3c
        checksum/dynamic-plugins: 'f1f9a92f14a31362d7eb30e67ac1458faf1c685765610f93a8967194d8bc1a5f'
    spec:
      serviceAccountName: default
      volumes:
        - ephemeral:
            volumeClaimTemplate:
              spec:
                accessModes:
                - ReadWriteOnce
                resources:
                  requests:
                    storage: 5Gi
          name: dynamic-plugins-root
        - configMap:
            defaultMode: 420
            name: 'release-name-dynamic-plugins'
            optional: true
          name: dynamic-plugins
        - name: dynamic-plugins-npmrc
          secret:
            defaultMode: 420
            optional: true
            secretName: 'release-name-dynamic-plugins-npmrc'
        - name: dynamic-plugins-registry-auth
          secret:
            defaultMode: 416
            optional: true
            secretName: 'release-name-dynamic-plugins-registry-auth'
        - emptyDir: {}
          name: npmcacache
        - emptyDir: {}
          name: temp
        - name: backstage-app-config
          configMap:
            name: release-name-developer-hub-app-config
      
      initContainers:
        - command:
          - ./install-dynamic-plugins.sh
          - /dynamic-plugins-root
          env:
          - name: NPM_CONFIG_USERCONFIG
            value: /opt/app-root/src/.npmrc.dynamic-plugins
          - name: MAX_ENTRY_SIZE
            value: "30000000"
          image: 'quay.io/rhdh/rhdh-hub-rhel9:latest'
          imagePullPolicy: Always
          name: install-dynamic-plugins
          resources:
            limits:
              cpu: 1000m
              ephemeral-storage: 5Gi
              memory: 2.5Gi
            requests:
              cpu: 250m
              memory: 256Mi
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              drop:
              - ALL
            readOnlyRootFilesystem: true
            runAsNonRoot: true
            seccompProfile:
              type: RuntimeDefault
          volumeMounts:
          - mountPath: /dynamic-plugins-root
            name: dynamic-plugins-root
          - mountPath: /opt/app-root/src/dynamic-plugins.yaml
            name: dynamic-plugins
            readOnly: true
            subPath: dynamic-plugins.yaml
          - mountPath: /opt/app-root/src/.npmrc.dynamic-plugins
            name: dynamic-plugins-npmrc
            readOnly: true
            subPath: .npmrc
          - mountPath: /opt/app-root/src/.config/containers
            name: dynamic-plugins-registry-auth
            readOnly: true
          - mountPath: /opt/app-root/src/.npm/_cacache
            name: npmcacache
          - mountPath: /tmp
            name: temp
          workingDir: /opt/app-root/src
      containers:
        - name: backstage-backend
          image: quay.io/rhdh/rhdh-hub-rhel9:latest
          imagePullPolicy: "Always"
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              drop:
              - ALL
            readOnlyRootFilesystem: true
            runAsNonRoot: true
            seccompProfile:
              type: RuntimeDefault
          args:
            - "--config"
            - "dynamic-plugins-root/app-config.dynamic-plugins.yaml"
            - "--config"
            - "/opt/app-root/src/app-config-from-configmap.yaml"
          resources:
            limits:
              cpu: 1000m
              ephemeral-storage: 5Gi
              memory: 2.5Gi
            requests:
              cpu: 250m
              memory: 1Gi
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /.backstage/health/v1/readiness
              port: backend
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 2
            timeoutSeconds: 4
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /.backstage/health/v1/liveness
              port: backend
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 4
          startupProbe:
            failureThreshold: 3
            httpGet:
              path: /.backstage/health/v1/liveness
              port: backend
              scheme: HTTP
            initialDelaySeconds: 30
            periodSeconds: 20
            successThreshold: 1
            timeoutSeconds: 4
          env:
            - name: APP_CONFIG_backend_listen_port
              value: "7007"
            - name: POSTGRES_HOST
              value: release-name-postgresql
            - name: POSTGRES_PORT
              value: "5432"
            - name: POSTGRES_USER
              value: bn_backstage
            - name: POSTGRES_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: release-name-postgresql
                  key: password
            -
              name: BACKEND_SECRET
              valueFrom:
                secretKeyRef:
                  key: backend-secret
                  name: 'release-name-auth'
            -
              name: HTTP_PROXY
              valueFrom:
                secretKeyRef:
                  key: http-proxy
                  name: my-super-secret
            -
              name: POSTGRESQL_ADMIN_PASSWORD
              valueFrom:
                secretKeyRef:
                  key: postgres-password
                  name: 'release-name-postgresql'
            -
              name: LOG_LEVEL
              value: debug
          ports:
            - name: backend
              containerPort: 7007
              protocol: TCP
          volumeMounts:
            - name: backstage-app-config
              mountPath: "/opt/app-root/src/app-config-from-configmap.yaml"
              subPath: app-config.yaml
            - mountPath: /opt/app-root/src/dynamic-plugins-root
              name: dynamic-plugins-root
            - mountPath: /tmp
              name: temp
---
[...]

• This other branch illustrates how the changes here remain 100% backward compatible when extraEnvVars is an array. See the test values file highlighting the current behavior where we need to replicate all the chart default elements.

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the values.yaml and added to the README.md. The helm-docs utility can be used to generate the necessary content. Use helm-docs --dry-run to preview the content.
• JSON Schema generated.
• List tests pass for Chart using the Chart Testing tool and the ct lint command.

[github-actions]

This PR has been automatically marked as stale because it has not had recent activity from the author. It will be closed if no further activity occurs. If the PR was closed and you want it re-opened, let us know and we'll re-open the PR so that you can continue the contribution!

[rm3l]

not stale

[github-actions]

This PR has been automatically marked as stale because it has not had recent activity from the author. It will be closed if no further activity occurs. If the PR was closed and you want it re-opened, let us know and we'll re-open the PR so that you can continue the contribution!

[rm3l]

not stale