Make backport action more customizable for other teams

backport/action.yml

@@ -1,9 +1,6 @@
 name: 'Backport Action'
 description: 'Backport merged pull requests to other branches via labels'
 inputs:
-  branch:
-    description: The target branch for merged pull requests
-    required: true
   github_token:
     description: An oauth token that will be used to create the backport pull requests and perform other operations
     required: true
@@ -13,6 +10,18 @@ inputs:
   commit_email:
     description: The e-mail address that will be used to commit the cherry-picks for the backport branches
     required: true
+  auto_merge:
+    description: Enable auto-merge for created backport PRs
+    required: false
+    default: 'true'
+  auto_merge_method:
+    description: 'When enabling auto-merge, sets the auto-merge method. Possible values are: merge, rebase, squash'
+    required: false
+    default: 'squash'
+  manual_backport_command_template:
+    description: ''
+    required: false
+    default: 'node scripts/backport --pr %pullNumber%'
 runs:
   using: 'node12'
   main: 'index.js'

backport/createStatusComment.test.ts

@@ -2,10 +2,12 @@ import { BackportResponse } from 'backport';
 import { expect } from 'chai';
 import { getCommentFromResponse } from './createStatusComment';
 
+const BACKPORT_TEMPLATE = 'node scripts/backport --pr %pullNumber%';
+
 describe('createStatusComment', () => {
   describe('getCommentFromResponse', () => {
     it('should create a message for all successful backports', async () => {
-      const comment = getCommentFromResponse(1, {
+      const comment = getCommentFromResponse(1, BACKPORT_TEMPLATE, {
         results: [
           {
             success: true,
@@ -31,7 +33,7 @@ Successful backport PRs will be merged automatically after passing CI.`,
     });
 
     it('should create a message for a mix of successful and failed backports', async () => {
-      const comment = getCommentFromResponse(1, {
+      const comment = getCommentFromResponse(1, BACKPORT_TEMPLATE, {
         results: [
           {
             success: true,
@@ -61,7 +63,7 @@ To backport manually, check out the target branch and run:
     });
 
     it('should create a message for a all failed backports', async () => {
-      const comment = getCommentFromResponse(1, {
+      const comment = getCommentFromResponse(1, BACKPORT_TEMPLATE, {
         results: [
           {
             success: false,

backport/createStatusComment.ts

@@ -1,7 +1,11 @@
 import { BackportResponse } from 'backport';
 import { Octokit } from '@octokit/rest';
 
-export const getCommentFromResponse = (pullNumber: number, backportResponse: BackportResponse): string => {
+export const getCommentFromResponse = (
+  pullNumber: number,
+  backportCommandTemplate: string,
+  backportResponse: BackportResponse,
+): string => {
   const hasAnySuccessful = !!backportResponse.results.find((r) => r.success);
 
   const header = backportResponse.success ? '## 💚 Backport successful' : '## 💔 Backport failed';
@@ -31,7 +35,7 @@ export const getCommentFromResponse = (pullNumber: number, backportResponse: Bac
     helpParts.push(
       [
         'To backport manually, check out the target branch and run:',
-        `\`node scripts/backport --pr ${pullNumber}\``,
+        `\`${backportCommandTemplate.replace('%pullNumber%', pullNumber.toString())}\``,
       ].join('\n'),
     );
   }
@@ -46,9 +50,10 @@ export default async function createStatusComment(options: {
   repoOwner: string;
   repoName: string;
   pullNumber: number;
+  backportCommandTemplate: string;
   backportResponse: BackportResponse;
 }) {
-  const { accessToken, repoOwner, repoName, pullNumber, backportResponse } = options;
+  const { accessToken, repoOwner, repoName, pullNumber, backportCommandTemplate, backportResponse } = options;
 
   const octokit = new Octokit({
     auth: accessToken,
@@ -58,6 +63,6 @@ export default async function createStatusComment(options: {
     owner: repoOwner,
     repo: repoName,
     issue_number: pullNumber,
-    body: getCommentFromResponse(pullNumber, backportResponse),
+    body: getCommentFromResponse(pullNumber, backportCommandTemplate, backportResponse),
   });
 }

backport/index.ts

@@ -21,11 +21,20 @@ async function backport() {
   const pullRequest = payload.pull_request;
   const owner: string = pullRequest.user.login;
 
-  const branch = core.getInput('branch', { required: true });
+  const branch: string = pullRequest?.base?.ref;
+
+  if (!branch) {
+    throw Error("Can't determine PR base branch.");
+  }
+
   const accessToken = core.getInput('github_token', { required: true });
   const commitUser = core.getInput('commit_user', { required: true });
   const commitEmail = core.getInput('commit_email', { required: true });
 
+  const autoMerge = core.getInput('auto_merge', { required: true }) === 'true';
+  const autoMergeMethod = core.getInput('auto_merge_method', { required: true });
+  const backportCommandTemplate = core.getInput('manual_backport_command_template', { required: true });
+
   await exec(`git config --global user.name "${commitUser}"`);
   await exec(`git config --global user.email "${commitEmail}"`);
 
@@ -40,15 +49,16 @@ async function backport() {
     pullNumber: pullRequest.number,
     labels: ['backport'],
     assignees: [owner],
-    autoMerge: true,
-    autoMergeMethod: 'squash',
+    autoMerge: autoMerge,
+    autoMergeMethod: autoMergeMethod,
   });
 
   await createStatusComment({
     accessToken,
     repoOwner: repo.owner,
     repoName: repo.repo,
     pullNumber: pullRequest.number,
+    backportCommandTemplate,
     backportResponse,
   });
 }