Comment on PR with link to PR artifact

Summary: Changelog: [Internal] Configure circleCI to comment on PR after building tarball

Reviewed By: hramos

Differential Revision: D31387660

fbshipit-source-id: 28902148cf5e2ea15320333b90a6a7fa9d553c3b

.circleci/config.yml

@@ -774,6 +774,13 @@ jobs:
             - store_artifacts:
                 path: ~/react-native/build/
                 destination: build
+      - when:
+          condition:
+            matches: { pattern: '^pull\/.*$', value: << pipeline.git.branch >> }
+          steps:
+            - run:
+                name: Post link to PR build artifacts (pull-bot)
+                command: GITHUB_TOKEN="$PUBLIC_PULLBOT_GITHUB_TOKEN_A""$PUBLIC_PULLBOT_GITHUB_TOKEN_B" scripts/circleci/post-artifacts-link.sh
 
   # -------------------------
   #    JOBS: Nightly

bots/post-artifacts-link.js

@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+'use strict';
+
+const {GITHUB_TOKEN, CIRCLE_BUILD_URL, GITHUB_SHA} = process.env;
+if (!GITHUB_TOKEN || !CIRCLE_BUILD_URL) {
+  if (!GITHUB_TOKEN) {
+    console.error("Missing GITHUB_TOKEN. This should've been set by the CI.");
+  }
+  if (!CIRCLE_BUILD_URL) {
+    console.error(
+      "Missing CIRCLE_BUILD_URL. This should've been set by the CI.",
+    );
+  }
+  process.exit(1);
+}
+
+const {createOrUpdateComment} = require('./make-comment');
+
+/**
+ * Creates or updates a comment with specified pattern.
+ * @param {string} buildURL link to circleCI build
+ * @param {string} commitSha github sha of PR
+ */
+function postArtifactLink(buildUrl, commitSha) {
+  const artifactLink = buildUrl + '/artifacts';
+  const comment = [
+    `PR build artifact${
+      commitSha != null ? ` for ${commitSha}` : ''
+    } is ready.`,
+    `To use, download tarball from [this CircleCI job](${artifactLink}) then run \`yarn add <path to tarball>\` in your React Native project.`,
+  ].join('\n');
+  createOrUpdateComment(comment);
+}
+
+try {
+  postArtifactLink(CIRCLE_BUILD_URL, GITHUB_SHA);
+} catch (error) {
+  console.error(error);
+  process.exitCode = 1;
+}

scripts/circleci/post-artifacts-link.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+GITHUB_OWNER=${CIRCLE_PROJECT_USERNAME:-facebook} \
+GITHUB_REPO=${CIRCLE_PROJECT_REPONAME:-react-native} \
+GITHUB_PR_NUMBER="${CIRCLE_PR_NUMBER:-${CIRCLE_PULL_REQUEST##*/}}" \
+GITHUB_SHA=${CIRCLE_SHA1} \
+exec node bots/post-artifacts-link.js