feat: Add CircleCI workflow rerun when a specific label is added to a PR

functions/src/default.ts

@@ -113,14 +113,22 @@ If you can't get the PR to a green state due to flakes or broken master, please
     l1TriageLabels: [["comp: *"]],
     // arrays of labels that determine if a PR has been fully triaged
     l2TriageLabels: [["type: *", "effort*", "risk*", "comp: *"]]
-  }
+  },
+
+  rerunCircleCI: {
+    // set to true to disable
+    disabled: true,
+    // the label which when added triggers a rerun of the default CircleCI workflow.
+    triggerRerunLabel: 'Trigger CircleCI Rerun';
+  },
 };
 
 export interface AppConfig {
   merge: MergeConfig;
   triage: TriageConfig;
   triagePR: TriagePRConfig;
   size: SizeConfig;
+  rerunCircleCI: RerunCircleCIConfig;
 }
 
 export interface MergeConfig {
@@ -187,3 +195,8 @@ export interface SizeConfig {
 export interface AdminConfig {
   allowInit: boolean;
 }
+
+export interface RerunCircleCIConfig {
+  disabled: boolean;
+  triggerRerunLabel: string;
+}

functions/src/plugins/rerun-circleci.ts

@@ -0,0 +1,95 @@
+import {config} from 'firebase-functions';
+import {Application, Context} from "probot";
+import {Task} from "./task";
+import {RerunCircleCIConfig} from "../default";
+import Github from '@octokit/rest';
+import fetch from "node-fetch";
+
+let circleCIConfig = config().circleCI.token;
+
+// Check if we are in Firebase or in development
+if(!circleCIConfig) {
+  // Use dev config
+  circleCIConfig = require('../../private/circle-ci.json');
+}
+
+const CIRCLE_CI_TOKEN = circleCIConfig.token;
+
+export class RerunCircleCITask extends Task {
+  constructor(robot: Application, db: FirebaseFirestore.Firestore) {
+    super(robot, db);
+
+    // Dispatch when a label is added to a pull request.
+    this.dispatch([
+      'pull_request.labeled',
+    ], this.checkRerunCircleCI.bind(this));
+  }
+
+  /** Determines if a circle rerun should occur. */
+  async checkRerunCircleCI(context: Context): Promise<void> {
+    const config = await this.getConfig(context);
+    if (config.disabled) {
+      return;
+    }
+
+    if (context.payload.label) {
+      const label: Github.IssuesGetLabelResponse = context.payload.label;
+      if (label.name === config.triggerRerunLabel) {
+        await this.triggerCircleCIRerun(context);
+      }
+    }
+  }
+
+  /** Triggers a rerun of the default CircleCI workflow and then removed the triggering label. */
+  async triggerCircleCIRerun(context: Context) {
+    const config = await this.getConfig(context);
+    if (config.disabled) {
+      return;
+    }
+
+    const pullRequest: Github.PullRequestsGetResponse = context.payload.pull_request;
+    const sender: Github.PullRequestsGetResponseUser = context.payload.sender;
+    const {owner, repo} = context.repo();
+    const circleCiUrl = `https://circleci.com/api/v1.1/project/github/${owner}/${repo}/build?circle-token=${CIRCLE_CI_TOKEN}`;
+    try {
+      await fetch(circleCiUrl, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({
+          revision: pullRequest.head.sha,
+          branch: `pull/${pullRequest.number}`,
+        })
+      });
+    } catch (err) {
+      const error: TypeError = err;
+      context.github.issues.createComment({
+        body: `@${sender.login} the CircleCI rerun you requested failed.  See details below:
+
+\`\`\`
+${error.message}
+\`\`\``,
+        number: pullRequest.number,
+        owner: owner,
+        repo: repo,
+      }) 
+
+    } 
+    await context.github.issues.removeLabel({
+      name: config.triggerRerunLabel,
+      number: pullRequest.number,
+      owner: owner,
+      repo: repo
+    });
+  }
+
+  /**
+   * Gets the config for the merge plugin from Github or uses default if necessary
+   */
+  async getConfig(context: Context): Promise<RerunCircleCIConfig> {
+    const repositoryConfig = await this.getAppConfig(context);
+    const config = repositoryConfig.rerunCircleCI;
+    return config;
+  }
+}

functions/src/util.ts

@@ -4,6 +4,8 @@ import {MergeTask} from "./plugins/merge";
 import {TriageTask} from "./plugins/triage";
 import {SizeTask} from "./plugins/size";
 import {TriagePRTask} from "./plugins/triagePR";
+import {RerunCircleCITask} from "./plugins/rerun-circleci";
+
 
 class Stream {
   constructor(private store: FirebaseFirestore.Firestore) {
@@ -96,6 +98,7 @@ export interface Tasks {
   triageTask: TriageTask;
   triagePRTask: TriagePRTask;
   sizeTask: SizeTask;
+  rerunCircleCiTask: RerunCircleCITask;
 }
 
 export function registerTasks(robot: Application, store: FirebaseFirestore.Firestore): Tasks {
@@ -106,6 +109,7 @@ export function registerTasks(robot: Application, store: FirebaseFirestore.Fires
     triageTask: new TriageTask(robot, store),
     triagePRTask: new TriagePRTask(robot, store),
     sizeTask: new SizeTask(robot, store),
+    rerunCircleCiTask: new RerunCircleCITask(robot, store),
   };
 }
 

test/fixtures/angular-robot.yml

@@ -167,3 +167,10 @@ triagePR:
       - "effort*"
       - "risk*"
       - "comp: *"
+
+# options for the rerun circleCI plugin
+rerunCircleCI:
+  # set to true to disable
+  disabled: true
+  # the label which when added triggers a rerun of the default CircleCI workflow.
+  triggerRerunLabel: 'Trigger CircleCI Rerun'