ci: publish helm chart to GitHub pages via GH action

.github/workflows/ci.yaml

@@ -63,12 +63,13 @@ jobs:
         run: |
           make test
 
-  # Builds all container images. For pushes to PRs/branches, we simply verify that the image build still works, the
-  # resulting image will not be pushed to any target registry. For pushes to the main branch, the images are tagged with
-  # "main", but not with a version x.y.z. Finally, for pushes to a tag (or when a tag is created), the images are tagged
-  # with the version indicated by the tag respectively, and also with latest. That is: Creating a GitHub release (or
-  # creating a git tag via other means) will trigger building images tagged with x.y.z meant for production use.
-  build-images:
+  # Builds and potentially pushes all container images. For pushes to PRs/branches, we simply verify that the image
+  # build still works, the resulting image will not be pushed to any target registry. For pushes to the main branch, the
+  # images are tagged with "main-dev", but not with a version x.y.z. Finally, for pushes to a tag (or when a tag is
+  # created), the images are tagged with the version indicated by the tag respectively, and also with latest. That is:
+  # Creating a GitHub release (or creating a git tag via other means) will trigger building images tagged with x.y.z
+  # meant for production use.
+  build-and-push-images:
     name: Build Images
     runs-on: ubuntu-latest
     needs:
@@ -134,3 +135,23 @@ jobs:
           imageTitle: Dash0 Kubernetes Operator Controller
           imageDescription: the controller for the Dash0 Kubernetes operator
           context: .
+
+  publish-helm-chart:
+    name: Publish Helm Chart
+    runs-on: ubuntu-latest
+    if: ${{ contains(github.ref, 'refs/tags/') }}
+    needs:
+      - build-and-push-images
+    concurrency:
+      group: ci-concurrency-group-${{ github.ref }}
+      cancel-in-progress: true
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: publish helm chart
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          echo "publishing helm chart version ${{ github.ref_name }}"
+          helm-chart/bin/publish.sh ${{ github.ref_name }}

helm-chart/bin/publish.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+
+# SPDX-FileCopyrightText: Copyright 2024 Dash0 Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+set -euo pipefail
+
+cd "$(dirname ${BASH_SOURCE})"/..
+
+# Abort when there are local changes in the repository. This is mostly relevant for testing the script locally.
+if ! git diff --quiet --exit-code; then
+  echo "error: The repository has local changes, aborting."
+  git --no-pager diff
+  exit 1
+fi
+
+version=${1:-}
+
+if [[ -z $version ]]; then
+  echo "Mandatory parameter version is missing."
+  echo "Usage: $0 <version>"
+  exit 1
+fi
+
+echo "packaging Helm chart as version $version"
+helm package \
+  dash0-operator \
+  --version $version \
+  --app-version $version \
+  --dependency-update \
+  --destination ..
+echo "packaging Helm version $version has been packaged"
+
+cd ..
+echo "switching to gh-pages branch"
+git fetch origin gh-pages:gh-pages
+git switch gh-pages
+
+# clean up potential left-overs from the --dependency-update flag
+rm -rf helm-chart
+
+echo "creating Helm chart index"
+helm repo index .
+
+echo "git add, commit & push"
+git add "dash0-operator-$version.tgz" index.yaml
+git commit -m"feat(chart): publish version $version"
+git push --no-verify --set-upstream origin gh-pages

helm-chart/dash0-operator/templates/_helpers.tpl

@@ -53,7 +53,11 @@ helm.sh/chart: {{ include "dash0-operator.chartNameWithVersion" . }}
 
 {{/* the init container image */}}
 {{- define "dash0-operator.initContainerImage" -}}
-{{- printf "%s:%s" .Values.operator.initContainerImage.repository .Values.operator.initContainerImage.tag }}
+{{- printf "%s:%s" .Values.operator.initContainerImage.repository (include "dash0-operator.initContainerImageTag" .)  }}
+{{- end }}
+
+{{- define "dash0-operator.initContainerImageTag" -}}
+{{- default .Chart.AppVersion .Values.operator.initContainerImage.tag }}
 {{- end }}
 
 {{- define "dash0-operator.restrictiveContainerSecurityContext" -}}

helm-chart/dash0-operator/tests/operator/__snapshot__/deployment_test.yaml.snap

@@ -39,10 +39,10 @@ deployment should match snapshot (default values):
                 - name: DASH0_OTEL_COLLECTOR_BASE_URL
                   value: http://RELEASE-NAME-opentelemetry-collector.NAMESPACE.svc.cluster.local:4318
                 - name: DASH0_OPERATOR_IMAGE
-                  value: dash0-operator-controller:1.0.0
+                  value: ghcr.io/dash0hq/operator-controller:1.0.0
                 - name: DASH0_INIT_CONTAINER_IMAGE
                   value: ghcr.io/dash0hq/instrumentation:1.0.0
-              image: dash0-operator-controller:1.0.0
+              image: ghcr.io/dash0hq/operator-controller:1.0.0
               livenessProbe:
                 httpGet:
                   path: /healthz

helm-chart/dash0-operator/tests/operator/__snapshot__/pre-delete-hook_test.yaml.snap

@@ -32,7 +32,7 @@ pre-delete hook job should match snapshot:
             - command:
                 - /manager
                 - --uninstrument-all
-              image: dash0-operator-controller:1.0.0
+              image: ghcr.io/dash0hq/operator-controller:1.0.0
               imagePullPolicy: null
               name: pre-delete-job
               resources:

helm-chart/dash0-operator/tests/operator/deployment_test.yaml

@@ -6,6 +6,27 @@ tests:
     asserts:
       - matchSnapshot: {}
 
+  - it: image tags should default to appVersion
+    chart:
+      version: 4.5.6
+      appVersion: 99.100.101
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].image
+          value: ghcr.io/dash0hq/operator-controller:99.100.101
+      - equal:
+          path: spec.template.spec.containers[0].env[1].name
+          value: DASH0_OPERATOR_IMAGE
+      - equal:
+          path: spec.template.spec.containers[0].env[1].value
+          value: ghcr.io/dash0hq/operator-controller:99.100.101
+      - equal:
+          path: spec.template.spec.containers[0].env[2].name
+          value: DASH0_INIT_CONTAINER_IMAGE
+      - equal:
+          path: spec.template.spec.containers[0].env[2].value
+          value: ghcr.io/dash0hq/instrumentation:99.100.101
+
   - it: should render deployment with custom settings
     set:
       operator:

helm-chart/dash0-operator/tests/operator/pre-delete-hook_test.yaml

@@ -4,4 +4,13 @@ templates:
 tests:
   - it: pre-delete hook job should match snapshot
     asserts:
-      - matchSnapshot: {}
+      - matchSnapshot: {}
+
+  - it: image tag should default to appVersion
+    chart:
+      version: 4.5.6
+      appVersion: 99.100.101
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[0].image
+          value: ghcr.io/dash0hq/operator-controller:99.100.101

helm-chart/dash0-operator/values.yaml

@@ -74,7 +74,7 @@ operator:
   image:
     # Use a different image entirely. Note that Dash0 does not offer support for Dash0 operator setups that do not use
     # Dash0's official image.
-    repository: "dash0-operator-controller"
+    repository: "ghcr.io/dash0hq/operator-controller"
     # overrides the image tag, which defaults to the chart appVersion.
     tag:
     # override the default image pull policy
@@ -86,8 +86,8 @@ operator:
     # Use a different image for the init container entirely. Note that Dash0 does not offer support for Dash0 operator
     # setups that do not use Dash0's official init container image.
     repository: "ghcr.io/dash0hq/instrumentation"
-    # overrides the image tag for the init container image
-    tag: "1.0.0"
+    # overrides the image tag, which defaults to the chart appVersion.
+    tag:
     # override the default image pull policy
     pullPolicy: