helm: Add helm chart tests (#20394)

* helm: Fix consistent list indentation

* helm: Add helm lint and helm template tests

* helm: Add helm template --validate test

* helm: Add helm install test

1 files changed, 138 insertions, 0 deletions

diff --git a/.github/workflows/test-chart.yml b/.github/workflows/test-chart.yml
new file mode 100644
index 000000000..b9ff80855
--- /dev/null
+++ b/.github/workflows/test-chart.yml
@@ -0,0 +1,138 @@
+# This is a GitHub workflow defining a set of jobs with a set of steps.
+# ref: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions
+#
+name: Test chart
+
+on:
+  pull_request:
+    paths:
+      - "chart/**"
+      - "!**.md"
+      - ".github/workflows/test-chart.yml"
+  push:
+    paths:
+      - "chart/**"
+      - "!**.md"
+      - ".github/workflows/test-chart.yml"
+    branches-ignore:
+      - "dependabot/**"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+defaults:
+  run:
+    working-directory: chart
+
+jobs:
+  lint-templates:
+    runs-on: ubuntu-22.04
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: "3.x"
+
+      - name: Install dependencies (yamllint)
+        run: pip install yamllint
+
+      - run: helm dependency update
+
+      - name: helm lint
+        run: |
+          helm lint . \
+              --values dev-values.yaml
+
+      - name: helm template
+        run: |
+          helm template . \
+              --values dev-values.yaml \
+              --output-dir rendered-templates
+
+      - name: yamllint (only on templates we manage)
+        run: |
+          rm -rf rendered-templates/mastodon/charts
+
+          yamllint rendered-templates \
+            --config-data "{rules: {indentation: {spaces: 2}, line-length: disable}}"
+
+  # This job helps us validate that rendered templates are valid k8s resources
+  # against a k8s api-server, via "helm template --validate", but also that a
+  # basic configuration can be used to successfully startup mastodon.
+  #
+  test-install:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 15
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # k3s-channel reference: https://update.k3s.io/v1-release/channels
+          - k3s-channel: latest
+          - k3s-channel: stable
+
+          # This represents the oldest configuration we test against.
+          #
+          # The k8s version chosen is based on the oldest still supported k8s
+          # version among two managed k8s services, GKE, EKS.
+          # - GKE: https://endoflife.date/google-kubernetes-engine
+          # - EKS: https://endoflife.date/amazon-eks
+          #
+          # The helm client's version can influence what helper functions is
+          # available for use in the templates, currently we need v3.6.0 or
+          # higher.
+          #
+          - k3s-channel: v1.21
+            helm-version: v3.6.0
+
+    steps:
+      - uses: actions/checkout@v3
+
+      # This action starts a k8s cluster with NetworkPolicy enforcement and
+      # installs both kubectl and helm.
+      #
+      # ref: https://github.com/jupyterhub/action-k3s-helm#readme
+      #
+      - uses: jupyterhub/action-k3s-helm@v3
+        with:
+          k3s-channel: ${{ matrix.k3s-channel }}
+          helm-version: ${{ matrix.helm-version }}
+          metrics-enabled: false
+          traefik-enabled: false
+          docker-enabled: false
+
+      - run: helm dependency update
+
+      # Validate rendered helm templates against the k8s api-server
+      - name: helm template --validate
+        run: |
+          helm template --validate mastodon . \
+              --values dev-values.yaml
+
+      - name: helm install
+        run: |
+          helm install mastodon . \
+              --values dev-values.yaml \
+              --timeout 10m
+
+      # This actions provides a report about the state of the k8s cluster,
+      # providing logs etc on anything that has failed and workloads marked as
+      # important.
+      #
+      # ref: https://github.com/jupyterhub/action-k8s-namespace-report#readme
+      #
+      - name: Kubernetes namespace report
+        uses: jupyterhub/action-k8s-namespace-report@v1
+        if: always()
+        with:
+          important-workloads: >-
+            deploy/mastodon-sidekiq
+            deploy/mastodon-streaming
+            deploy/mastodon-web
+            job/mastodon-assets-precompile
+            job/mastodon-chewy-upgrade
+            job/mastodon-create-admin
+            job/mastodon-db-migrate