build: Compare current chart to latest released (#362)

I've added a step to the helm-workflow, that is adding an annotation to
the helm chart manifests. This annotations contains a SHA of a current
commit. If the action is triggered by puhsing to the master, this
annotations will be preserved and will make it to the upstream
manifests, though it's not visible in the git repo.

I'm adding to identify the the commit to which we should compare the
current version of the chart. If it's not accessible, the chart will be
compared to the previous commit, that basically means that there is no
released version yet.

I've also added a repo URL to chart annotations, so we can get the chart
from the upstream repo to retrieve the SHA annotations from the upstream
chart. It should make it possible to use the same workflow in forked
repos, if an intention behind forking is merging something to the
upstream repo.

.github/workflows/helm-workflow.yaml

@@ -1,4 +1,3 @@
----
 name: Helm
 on:
   push:
@@ -7,7 +6,11 @@ on:
   pull_request:
     branches:
       - master
-
+env:
+  HELM_VERSION: 3.12.1
+  PYTHON_VERSION: 3.9
+  TARGET_BRANCH: chart-testing-target-branch
+  TARGET_REMOTE: test
 jobs:
   helm-jobs:
     runs-on: ubuntu-latest
@@ -16,62 +19,95 @@ jobs:
         uses: actions/checkout@v3
         with:
           fetch-depth: 0
-
       - name: Set up Helm
         uses: azure/setup-helm@v3
         with:
-          version: v3.12.1
-
+          version: "v${{ env.HELM_VERSION }}"
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.9'
+          python-version: ${{ env.PYTHON_VERSION }}
           check-latest: true
-
+      # ---------------------------------------------------------------
+      # -- Instead of comparing to the master branch, I'm getting
+      # --  the commit hash set in the previous step from a
+      # --  currently released chart. If it doesn't exists, then
+      # --  I assume that chart is not released and compare to the
+      # --  previous commit 
+      # --
+      # -- Also, I'm setting the RepoURL here. Since we plan to support
+      # --  the official chart in this git repository, the helm
+      # --  repository is expected to belong to this repo as well.
+      # ---------------------------------------------------------------
+      - name: Retrieve the latest commit sha from the helm chart
+        run: |
+          HELM_REPO_URL="https://${GITHUB_REPOSITORY_OWNER}.github.io/${GITHUB_REPOSITORY#*/}"
+          if helm repo add sql-exporter $HELM_REPO_URL
+          then
+            helm repo update
+            echo "TARGET_COMMIT=$(helm show chart sql-exporter/sql-exporter | yq '.annotations.git/commit-sha')" >> "${GITHUB_ENV}"
+          else
+            echo "TARGET_COMMIT=$(git show HEAD^1 --pretty=format:%H --no-patch)" >> "${GITHUB_ENV}"
+          fi
+      # ---------------------------------------------------------------
+      # -- As I could find CT doesn't support testing against commits
+      # --  directly, so I'm creating a new fake remote from a commit
+      # --  and testing the chart against it. This workaround doesn't
+      # --  support maintainers validation, but we have it disabled
+      # --  anyway
+      # ---------------------------------------------------------------
+      - name: Prepare a dummy remote to test the chart
+        run: |
+          DUMMY_REMOTE=$(mktemp -d)
+          git init "${DUMMY_REMOTE}"
+          git remote add "${TARGET_REMOTE}" "${DUMMY_REMOTE}"
+          git checkout -b "${TARGET_BRANCH}" "${TARGET_COMMIT}"
+          git push --set-upstream "${TARGET_REMOTE}" "${TARGET_BRANCH}"
+          git checkout "${GITHUB_SHA}"
       - name: Set up chart-testing
         uses: helm/[email protected]
-
       - name: Run chart-testing (list-changed)
         id: list-changed
         run: |
-          changed=$(ct list-changed --chart-dirs . --target-branch ${{ github.event.repository.default_branch }})
+          changed=$(ct list-changed --chart-dirs . --target-branch "${TARGET_BRANCH}" --remote "${TARGET_REMOTE}")
           if [[ -n "$changed" ]]; then
             echo "changed=true" >> "$GITHUB_OUTPUT"
           fi
-
       - name: Run chart-testing (lint)
         if: steps.list-changed.outputs.changed == 'true'
-        run: ct lint --target-branch ${{ github.event.repository.default_branch }} --validate-maintainers=false --chart-dirs .
-
+        run: ct lint --target-branch "${TARGET_BRANCH}" --remote "${TARGET_REMOTE}" --validate-maintainers=false --chart-dirs .
       - name: Setup helmfile
         if: steps.list-changed.outputs.changed == 'true'
-        uses: mamezou-tech/[email protected]          
-
+        uses: mamezou-tech/[email protected]
       - name: Create kind cluster
         if: steps.list-changed.outputs.changed == 'true'
         uses: helm/[email protected]
-
       - name: Init postgres server
         if: steps.list-changed.outputs.changed == 'true'
         run: |
           helmfile -f helm/ci/helmfile.yaml sync
-
       - name: Run chart-testing (install)
         if: steps.list-changed.outputs.changed == 'true'
-        run: ct install --target-branch ${{ github.event.repository.default_branch }} --chart-dirs .
-
+        run: ct install --target-branch "${TARGET_BRANCH}" --remote "${TARGET_REMOTE}" --chart-dirs .
       - name: Run chart-testing (upgrade)
         if: steps.list-changed.outputs.changed == 'true'
-        run: ct install --target-branch ${{ github.event.repository.default_branch }} --chart-dirs . --upgrade
-
+        run: ct install --target-branch "${TARGET_BRANCH}" --remote "${TARGET_REMOTE}" --chart-dirs . --upgrade
       - name: Configure Git
         run: |
           git config user.name "$GITHUB_ACTOR"
           git config user.email "[email protected]"
+      # ---------------------------------------------------------------
+      # -- On each run we're setting an annotation with the current
+      # --  commit hash, so in case it's released, we will see it
+      # --  running `$ helm show sql-exporter/sql-exporter`
+      # ---------------------------------------------------------------
+      - name: Set the git sha annotations in the helm chart
+        run: yq -i ".annotations.git/commit-sha = \"${GITHUB_SHA}\"" ./helm/Chart.yaml
 
       - name: Release charts
-        if: ${{ github.ref == github.event.repository.default_branch }}
+        if: ${{ github.event.repository.default_branch && github.event_name == 'push' }}
         uses: helm/[email protected]
         with:
           charts_dir: .
+          mark_as_latest: false
         env:
           CR_TOKEN: "${{ secrets.GITHUB_TOKEN }}"

helm/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: sql-exporter
 description: Database agnostic SQL exporter for Prometheus
 type: application
-version: 0.1.2
+version: 0.1.3
 appVersion: 0.12.3
 keywords:
   - exporter