ci: Introduce commit message check

.github/workflows/commit-message-check.yaml

@@ -0,0 +1,99 @@
+name: Commit Message Check
+on:
+  pull_request:
+    types:
+      - opened
+      - reopened
+      - synchronize
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+env:
+  error_msg: |+
+    See the document below for help on formatting commits for the project.
+    https://github.com/kata-containers/community/blob/main/CONTRIBUTING.md#patch-format
+jobs:
+  commit-message-check:
+    runs-on: ubuntu-22.04
+    env:
+      PR_AUTHOR: ${{ github.event.pull_request.user.login }}
+    name: Commit Message Check
+    steps:
+    - name: Get PR Commits
+      if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') }}
+      id: 'get-pr-commits'
+      uses: tim-actions/[email protected]
+      with:
+        token: ${{ secrets.GITHUB_TOKEN }}
+        # Filter out revert commits
+        # The format of a revert commit is as follows:
+        #
+        # Revert "<original-subject-line>"
+        #
+        # The format of a re-re-vert commit as follows:
+        #
+        # Reapply "<original-subject-line>"
+        filter_out_pattern: '^Revert "|^Reapply "'
+
+    - name: DCO Check
+      if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') }}
+      uses: tim-actions/dco@2fd0504dc0d27b33f542867c300c60840c6dcb20
+      with:
+        commits: ${{ steps.get-pr-commits.outputs.commits }}
+
+    - name: Commit Body Missing Check
+      if: ${{ !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && ( success() || failure() ) }}
+      uses: tim-actions/[email protected]
+      with:
+        commits: ${{ steps.get-pr-commits.outputs.commits }}
+
+    - name: Check Subject Line Length
+      if: ${{ (env.PR_AUTHOR != 'dependabot[bot]') && !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && ( success() || failure() ) }}
+      uses: tim-actions/[email protected]
+      with:
+        commits: ${{ steps.get-pr-commits.outputs.commits }}
+        pattern: '^.{0,75}(\n.*)*$'
+        error: 'Subject too long (max 75)'
+        post_error: ${{ env.error_msg }}
+
+    - name: Check Body Line Length
+      if: ${{ (env.PR_AUTHOR != 'dependabot[bot]') && !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && ( success() || failure() ) }}
+      uses: tim-actions/[email protected]
+      with:
+        commits: ${{ steps.get-pr-commits.outputs.commits }}
+        # Notes:
+        #
+        # - The subject line is not enforced here (see other check), but has
+        #   to be specified at the start of the regex as the action is passed
+        #   the entire commit message.
+        #
+        # - This check will pass if the commit message only contains a subject
+        #   line, as other body message properties are enforced elsewhere.
+        #
+        # - Body lines *can* be longer than the maximum if they start
+        #   with a non-alphabetic character or if there is no whitespace in
+        #   the line.
+        #
+        #   This allows stack traces, log files snippets, emails, long URLs,
+        #   etc to be specified. Some of these naturally "work" as they start
+        #   with numeric timestamps or addresses. Emails can but quoted using
+        #   the normal ">" character, markdown bullets ("-", "*") are also
+        #   useful for lists of URLs, but it is always possible to override
+        #   the check by simply space indenting the content you need to add.
+        #
+        # - A SoB comment can be any length (as it is unreasonable to penalise
+        #   people with long names/email addresses :)
+        pattern: '(^[^\n]+$|^.+(\n([a-zA-Z].{0,150}|[^a-zA-Z\n].*|[^\s\n]*|Signed-off-by:.*|))+$)'
+        error: 'Body line too long (max 150)'
+        post_error: ${{ env.error_msg }}
+
+    - name: Check Subsystem
+      if: ${{ (env.PR_AUTHOR != 'dependabot[bot]') && !contains(github.event.pull_request.labels.*.name, 'force-skip-ci') && ( success() || failure() ) }}
+      uses: tim-actions/[email protected]
+      with:
+        commits: ${{ steps.get-pr-commits.outputs.commits }}
+        pattern: '^[\s\t]*[^:\s\t]+[\s\t]*:'
+        error: 'Failed to find subsystem in subject'
+        post_error: ${{ env.error_msg }}