Adding auto backport (#146) (#151)

Signed-off-by: David Zane <[email protected]>
(cherry picked from commit 9a83315)
Signed-off-by: David Zane <[email protected]>

Co-authored-by: David Z <[email protected]>

.github/workflows/backport.yml

@@ -0,0 +1,28 @@
+name: Backport
+on:
+  pull_request_target:
+    types:
+      - closed
+      - labeled
+
+jobs:
+  backport:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    name: Backport
+    steps:
+      - name: GitHub App token
+        id: github_app_token
+        uses: tibdex/[email protected]
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.APP_PRIVATE_KEY }}
+          installation_id: 22958780
+
+      - name: Backport
+        uses: VachaShah/[email protected]
+        with:
+          github_token: ${{ steps.github_app_token.outputs.token }}
+          branch_name: backport/backport-${{ github.event.number }}

.github/workflows/delete_backport_branch.yml

@@ -0,0 +1,15 @@
+name: Delete merged branch of the backport PRs
+on:
+  pull_request:
+    types:
+      - closed
+
+jobs:
+  delete-branch:
+    runs-on: ubuntu-latest
+    if: startsWith(github.event.pull_request.head.ref,'backport/')
+    steps:
+      - name: Delete merged branch
+        uses: SvanBoxel/delete-merged-branch@main
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

DEVELOPER_GUIDE.md

@@ -36,4 +36,12 @@ Launch Intellij IDEA, choose **Import Project**, and select the `build.gradle` f
 
 ### Submitting Changes
 
-See [CONTRIBUTING](CONTRIBUTING.md).
+See [CONTRIBUTING](CONTRIBUTING.md).
+
+### Backports
+
+The Github workflow in [`backport.yml`](.github/workflows/backport.yml) creates backport PRs automatically when the
+original PR with an appropriate label `backport <backport-branch-name>` is merged to main with the backport workflow
+run successfully on the PR. For example, if a PR on main needs to be backported to `1.x` branch, add a label
+`backport 1.x` to the PR and make sure the backport workflow runs on the PR along with other checks. Once this PR is
+merged to main, the workflow will create a backport PR to the `1.x` branch.