app_dart/lib/src/request_handlers/github_webhook.dart - mirrors/cocoon - Git at Google

 // Copyright 2019 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';

 import 'package:cocoon_service/src/model/github/checks.dart';
 import 'package:cocoon_service/src/service/github_checks_service.dart';
 import 'package:cocoon_service/src/service/github_status_service.dart';
 import 'package:cocoon_service/src/service/luci_build_service.dart';
 import 'package:crypto/crypto.dart';
 import 'package:github/github.dart';
 import 'package:github/hooks.dart';
 import 'package:meta/meta.dart';

 import '../datastore/cocoon_config.dart';

 import '../request_handling/body.dart';
 import '../request_handling/exceptions.dart';
 import '../request_handling/request_handler.dart';
 import '../service/buildbucket.dart';

 /// List of repos that require CQ+1 label.
 const Set<String> kNeedsCQLabelList = <String>{'flutter/flutter'};

 /// List of repos that require check for golden triage.
 const Set<String> kNeedsCheckGoldenTriage = <String>{'flutter/flutter'};

 /// List of repos that require check for labels and tests.
 const Set<String> kNeedsCheckLabelsAndTests = <String>{
   'flutter/flutter',
   'flutter/engine'
 };

 final RegExp kEngineTestRegExp = RegExp(r'tests?\.(dart|java|mm|m|cc)$');

 @immutable
 class GithubWebhook extends RequestHandler<Body> {
   GithubWebhook(Config config, this.buildBucketClient, this.luciBuildService,
       this.githubStatusService, this.githubChecksService,
       {HttpClient skiaClient})
       : assert(buildBucketClient != null),
         skiaClient = skiaClient ?? HttpClient(),
         super(config: config);

   /// A client for querying and scheduling LUCI Builds.
   final BuildBucketClient buildBucketClient;

   /// An Http Client for querying the Skia Gold API.
   final HttpClient skiaClient;

   /// Github status service to update the state of the build
   /// in the Github UI.
   final GithubStatusService githubStatusService;

   /// LUCI service class to communicate with buildBucket service.
   final LuciBuildService luciBuildService;

   /// Github checks service. Used to provide build status to github.
   final GithubChecksService githubChecksService;

   @override
   Future<Body> post() async {
     final String gitHubEvent = request.headers.value('X-GitHub-Event');
     if (gitHubEvent == null ||
         request.headers.value('X-Hub-Signature') == null) {
       throw const BadRequestException('Missing required headers.');
     }
     final List<int> requestBytes = await request.expand((_) => _).toList();
     final String hmacSignature = request.headers.value('X-Hub-Signature');
     if (!await _validateRequest(hmacSignature, requestBytes)) {
       throw const Forbidden();
     }

     try {
       final String stringRequest = utf8.decode(requestBytes);
       switch (gitHubEvent) {
         case 'pull_request':
           await _handlePullRequest(stringRequest);
           break;
         case 'check_suite':
           final CheckSuiteEvent checkSuiteEvent = CheckSuiteEvent.fromJson(
             jsonDecode(stringRequest) as Map<String, dynamic>,
           );
           await githubChecksService.handleCheckSuite(
               checkSuiteEvent, luciBuildService);
           break;
         case 'check_run':
           final CheckRunEvent checkRunEvent = CheckRunEvent.fromJson(
             jsonDecode(stringRequest) as Map<String, dynamic>,
           );
           await githubChecksService.handleCheckRun(
               checkRunEvent, luciBuildService);
       }

       return Body.empty;
     } on FormatException {
       throw const BadRequestException('Could not process input data.');
     } on InternalServerError {
       rethrow;
     }
   }

   Future<void> _handlePullRequest(
     String rawRequest,
   ) async {
     final PullRequestEvent pullRequestEvent =
         await _getPullRequestEvent(rawRequest);
     if (pullRequestEvent == null) {
       throw const BadRequestException('Expected pull request event.');
     }
     final String eventAction = pullRequestEvent.action;
     final PullRequest pr = pullRequestEvent.pullRequest;

     // See the API reference:
     // https://developer.github.com/v3/activity/events/types/#pullrequestevent
     // which unfortunately is a bit light on explanations.
     switch (eventAction) {
       case 'closed':
         // On a successful merge, check for gold.
         // If it was closed without merging, cancel any outstanding tryjobs.
         // We'll leave unfinished jobs if it was merged since we care about those
         // results.
         if (pr.merged) {
           await _checkForGoldenTriage(pullRequestEvent);
         } else {
           await luciBuildService.cancelBuilds(
             pullRequestEvent.repository.slug(),
             pr.number,
             pr.head.sha,
             'Pull request closed',
           );
         }
         break;
       case 'edited':
         // Editing a PR should not trigger new jobs, but may update whether
         // it has tests.
         await _checkForLabelsAndTests(pullRequestEvent);
         break;
       case 'opened':
       case 'ready_for_review':
       case 'reopened':
         // These cases should trigger LUCI jobs.
         await _checkForLabelsAndTests(pullRequestEvent);
         await _scheduleIfMergeable(pullRequestEvent);
         break;
       case 'labeled':
         // This should only trigger a LUCI job for flutter/flutter right now,
         // since it is in the needsCQLabelList.
         if (kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
           await _scheduleIfMergeable(pullRequestEvent);
         }
         break;
       case 'synchronize':
         // This indicates the PR has new commits. We need to cancel old jobs
         // and schedule new ones.
         await _scheduleIfMergeable(pullRequestEvent);
         break;
       case 'unlabeled':
         // Cancel the jobs if someone removed the label on a repo that needs
         // them.
         if (!kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
           break;
         }
         if (!await _checkForCqLabel(pr.labels)) {
           await luciBuildService.cancelBuilds(
             pullRequestEvent.repository.slug(),
             pr.number,
             pr.head.sha,
             'Tryjobs canceled (label removed)',
           );
         }
         break;
       // Ignore the rest of the events.
       case 'assigned':
       case 'locked':
       case 'review_request_removed':
       case 'review_requested':
       case 'unassigned':
       case 'unlocked':
         break;
     }
   }

   /// This method assumes that jobs should be cancelled if they are already
   /// runnning. [githubStatusService] is used to update the status of a build
   /// in the GitHub UI. When the build is triggered the status is set to "pending"
   /// without a details link. Once the test starts running then the state is set
   /// to "pending" with a details link pointing to the build in LUCI infrastructure.
   Future<void> _scheduleIfMergeable(
     PullRequestEvent pullRequestEvent,
   ) async {
     // The mergeable flag may be null. False indicates there's a merge conflict,
     // null indicates unknown. Err on the side of allowing the job to run.
     final PullRequest pr = pullRequestEvent.pullRequest;
     // For flutter/flutter tests need to be optimized before enforcing CQ.
     if (kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
       if (!await _checkForCqLabel(pr.labels)) {
         return;
       }
     }

     // Always cancel running builds so we don't ever schedule duplicates.
     await luciBuildService.cancelBuilds(
       pullRequestEvent.repository.slug(),
       pr.number,
       pr.head.sha,
       'Newer commit available',
     );
     await luciBuildService.scheduleBuilds(
       slug: pullRequestEvent.repository.slug(),
       prNumber: pr.number,
       commitSha: pr.head.sha,
     );
     await githubStatusService.setBuildsPendingStatus(
         pr.number, pr.head.sha, pr.head.repo.slug());
   }

   /// Checks the issue in the given repository for `config.cqLabelName`.
   Future<bool> _checkForCqLabel(List<IssueLabel> labels) async {
     final String cqLabelName = config.cqLabelName;
     return labels.any((IssueLabel label) => label.name == cqLabelName);
   }

   Future<bool> _isIgnoredForGold(String eventAction, PullRequest pr) async {
     bool ignored = false;
     String rawResponse;
     try {
       final HttpClientRequest request = await skiaClient
           .getUrl(Uri.parse('https://flutter-gold.skia.org/json/ignores'));
       final HttpClientResponse response = await request.close();
       rawResponse = await utf8.decodeStream(response);
       final List<dynamic> ignores = jsonDecode(rawResponse) as List<dynamic>;
       for (Map<String, dynamic> ignore
           in ignores.cast<Map<String, dynamic>>()) {
         if ((ignore['note'] as String).isNotEmpty &&
             pr.number.toString() == ignore['note'].split('/').last) {
           ignored = true;
           break;
         }
       }
     } on IOException catch (e) {
       log.error('Request to Flutter Gold for ignores failed for PR '
           '#${pr.number} on action: $eventAction.\n'
           'error: $e');
     } on FormatException catch (_) {
       log.error('Format Exception from Flutter Gold ignore request.\n'
           'rawResponse: $rawResponse');
       rethrow;
     }
     return ignored;
   }

   Future<void> _checkForGoldenTriage(PullRequestEvent pullRequestEvent) async {
     final PullRequest pr = pullRequestEvent.pullRequest;
     final String eventAction = pullRequestEvent.action;
     final RepositorySlug slug = pullRequestEvent.repository.slug();
     if (kNeedsCheckGoldenTriage.contains(pr.base.repo.fullName.toLowerCase()) &&
         await _isIgnoredForGold(eventAction, pr)) {
       final GitHub gitHubClient =
           await config.createGitHubClient(slug.owner, slug.name);
       try {
         await _pingForTriage(gitHubClient, pr);
       } finally {
         gitHubClient.dispose();
       }
     }
   }

   Future<void> _pingForTriage(GitHub gitHubClient, PullRequest pr) async {
     final String body = config.goldenTriageMessage;
     final RepositorySlug slug = pr.base.repo.slug();
     await gitHubClient.issues.createComment(slug, pr.number, body);
   }

   Future<void> _checkForLabelsAndTests(
       PullRequestEvent pullRequestEvent) async {
     final PullRequest pr = pullRequestEvent.pullRequest;
     final String eventAction = pullRequestEvent.action;
     final RepositorySlug slug = pullRequestEvent.repository.slug();
     final String repo = pr.base.repo.fullName.toLowerCase();
     if (kNeedsCheckLabelsAndTests.contains(repo)) {
       final GitHub gitHubClient =
           await config.createGitHubClient(slug.owner, slug.name);
       try {
         await _checkBaseRef(gitHubClient, pr);
         if (repo == 'flutter/flutter') {
           await _applyFrameworkRepoLabels(gitHubClient, eventAction, pr);
         } else if (repo == 'flutter/engine') {
           await _applyEngineRepoLabels(gitHubClient, eventAction, pr);
         }
       } finally {
         gitHubClient.dispose();
       }
     }
   }

   Future<void> _applyFrameworkRepoLabels(
       GitHub gitHubClient, String eventAction, PullRequest pr) async {
     if (pr.user.login == 'engine-flutter-autoroll') {
       return;
     }
     final RepositorySlug slug = pr.base.repo.slug();
     final Stream<PullRequestFile> files =
         gitHubClient.pullRequests.listFiles(slug, pr.number);
     final Set<String> labels = <String>{};
     bool hasTests = false;
     bool needsTests = false;
     bool isGoldenChange = false;

     await for (PullRequestFile file in files) {
       if (file.filename.endsWith('pubspec.yaml')) {
         // These get updated by a script, and are updated en masse.
         labels.add('team');
         continue;
       }
       if (file.filename.endsWith('.dart')) {
         needsTests = true;
       }
       if (file.filename.endsWith('_test.dart')) {
         hasTests = true;
       }

       if (file.filename.startsWith('dev/')) {
         labels.add('team');
       }
       if (file.filename.startsWith('packages/flutter_tools/') ||
           file.filename.startsWith('packages/fuchsia_remote_debug_protocol')) {
         labels.add('tool');
       }
       if (file.filename == 'bin/internal/engine.version') {
         labels.add('engine');
       }
       if (await _isIgnoredForGold(eventAction, pr)) {
         isGoldenChange = true;
         labels.add('will affect goldens');
         labels.add('severe: API break');
         labels.add('a: tests');
       }

       if (file.filename.startsWith('packages/flutter/') ||
           file.filename.startsWith('packages/flutter_test/') ||
           file.filename.startsWith('packages/flutter_driver/')) {
         labels.add('framework');
       }
       if (file.filename.contains('material')) {
         labels.add('f: material design');
       }
       if (file.filename.contains('cupertino')) {
         labels.add('f: cupertino');
       }

       if (file.filename.startsWith('packages/flutter_localizations')) {
         labels.add('a: internationalization');
       }

       if (file.filename.startsWith('packages/flutter_test') ||
           file.filename.startsWith('packages/flutter_driver')) {
         labels.add('a: tests');
       }

       if (file.filename.contains('semantics') ||
           file.filename.contains('accessibilty')) {
         labels.add('a: accessibility');
       }

       if (file.filename.startsWith('examples/')) {
         labels.add('d: examples');
         labels.add('team');
         if (file.filename.startsWith('examples/flutter_gallery')) {
           labels.add('team: gallery');
         }
       }
     }

     if (pr.draft) {
       labels.add('work in progress; do not review');
     }

     if (labels.isNotEmpty) {
       await gitHubClient.issues
           .addLabelsToIssue(slug, pr.number, labels.toList());
     }

     if (!hasTests && needsTests && !pr.draft) {
       final String body = config.missingTestsPullRequestMessage;
       if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
         await gitHubClient.issues.createComment(slug, pr.number, body);
       }
     }

     if (isGoldenChange) {
       final String body = config.goldenBreakingChangeMessage;
       if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
         await gitHubClient.issues.createComment(slug, pr.number, body);
       }
     }
   }

   Future<void> _applyEngineRepoLabels(
       GitHub gitHubClient, String eventAction, PullRequest pr) async {
     if (pr.user.login == 'skia-flutter-autoroll') {
       return;
     }
     final RepositorySlug slug = pr.base.repo.slug();
     final Stream<PullRequestFile> files =
         gitHubClient.pullRequests.listFiles(slug, pr.number);
     final Set<String> labels = <String>{};
     bool hasTests = false;
     bool needsTests = false;

     await for (PullRequestFile file in files) {
       final String filename = file.filename.toLowerCase();
       if (filename.endsWith('.dart') ||
           filename.endsWith('.mm') ||
           filename.endsWith('.m') ||
           filename.endsWith('.java') ||
           filename.endsWith('.cc')) {
         needsTests = true;
       }

       if (kEngineTestRegExp.hasMatch(filename)) {
         hasTests = true;
       }

       if (filename.startsWith('shell/platform/darwin/ios')) {
         labels.add('platform-ios');
       }

       if (filename.startsWith('shell/platform/android')) {
         labels.add('platform-android');
       }
     }

     if (labels.isNotEmpty) {
       await gitHubClient.issues
           .addLabelsToIssue(slug, pr.number, labels.toList());
     }

     if (!hasTests && needsTests && !pr.draft) {
       final String body = config.missingTestsPullRequestMessage;
       if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
         await gitHubClient.issues.createComment(slug, pr.number, body);
       }
     }
   }

   Future<void> _checkBaseRef(
     GitHub gitHubClient,
     PullRequest pr,
   ) async {
     if (pr.base.ref != 'master') {
       final String body = await _getWrongBaseComment(pr.base.ref);
       final RepositorySlug slug = pr.base.repo.slug();
       if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
         await gitHubClient.pullRequests.edit(
           slug,
           pr.number,
           base: 'master',
         );
         await gitHubClient.issues.createComment(slug, pr.number, body);
       }
     }
   }

   Future<bool> _alreadyCommented(
     GitHub gitHubClient,
     PullRequest pr,
     RepositorySlug slug,
     String message,
   ) async {
     final Stream<IssueComment> comments =
         gitHubClient.issues.listCommentsByIssue(slug, pr.number);
     await for (IssueComment comment in comments) {
       if (comment.body.contains(message)) {
         return true;
       }
     }
     return false;
   }

   Future<String> _getWrongBaseComment(String base) async {
     final String messageTemplate = config.nonMasterPullRequestMessage;
     return messageTemplate.replaceAll('{{branch}}', base);
   }

   Future<bool> _validateRequest(
     String signature,
     List<int> requestBody,
   ) async {
     final String rawKey = await config.webhookKey;
     final List<int> key = utf8.encode(rawKey);
     final Hmac hmac = Hmac(sha1, key);
     final Digest digest = hmac.convert(requestBody);
     final String bodySignature = 'sha1=$digest';
     return bodySignature == signature;
   }

   Future<PullRequestEvent> _getPullRequestEvent(String request) async {
     if (request == null) {
       return null;
     }
     try {
       return PullRequestEvent.fromJson(
           json.decode(request) as Map<String, dynamic>);
     } on FormatException {
       return null;
     }
   }
 }
	// Copyright 2019 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';
	import 'dart:convert';
	import 'dart:io';

	import 'package:cocoon_service/src/model/github/checks.dart';
	import 'package:cocoon_service/src/service/github_checks_service.dart';
	import 'package:cocoon_service/src/service/github_status_service.dart';
	import 'package:cocoon_service/src/service/luci_build_service.dart';
	import 'package:crypto/crypto.dart';
	import 'package:github/github.dart';
	import 'package:github/hooks.dart';
	import 'package:meta/meta.dart';

	import '../datastore/cocoon_config.dart';

	import '../request_handling/body.dart';
	import '../request_handling/exceptions.dart';
	import '../request_handling/request_handler.dart';
	import '../service/buildbucket.dart';

	/// List of repos that require CQ+1 label.
	const Set<String> kNeedsCQLabelList = <String>{'flutter/flutter'};

	/// List of repos that require check for golden triage.
	const Set<String> kNeedsCheckGoldenTriage = <String>{'flutter/flutter'};

	/// List of repos that require check for labels and tests.
	const Set<String> kNeedsCheckLabelsAndTests = <String>{
	'flutter/flutter',
	'flutter/engine'
	};

	final RegExp kEngineTestRegExp = RegExp(r'tests?\.(dart\|java\|mm\|m\|cc)$');

	@immutable
	class GithubWebhook extends RequestHandler<Body> {
	GithubWebhook(Config config, this.buildBucketClient, this.luciBuildService,
	this.githubStatusService, this.githubChecksService,
	{HttpClient skiaClient})
	: assert(buildBucketClient != null),
	skiaClient = skiaClient ?? HttpClient(),
	super(config: config);

	/// A client for querying and scheduling LUCI Builds.
	final BuildBucketClient buildBucketClient;

	/// An Http Client for querying the Skia Gold API.
	final HttpClient skiaClient;

	/// Github status service to update the state of the build
	/// in the Github UI.
	final GithubStatusService githubStatusService;

	/// LUCI service class to communicate with buildBucket service.
	final LuciBuildService luciBuildService;

	/// Github checks service. Used to provide build status to github.
	final GithubChecksService githubChecksService;

	@override
	Future<Body> post() async {
	final String gitHubEvent = request.headers.value('X-GitHub-Event');
	if (gitHubEvent == null \|\|
	request.headers.value('X-Hub-Signature') == null) {
	throw const BadRequestException('Missing required headers.');
	}
	final List<int> requestBytes = await request.expand((_) => _).toList();
	final String hmacSignature = request.headers.value('X-Hub-Signature');
	if (!await _validateRequest(hmacSignature, requestBytes)) {
	throw const Forbidden();
	}

	try {
	final String stringRequest = utf8.decode(requestBytes);
	switch (gitHubEvent) {
	case 'pull_request':
	await _handlePullRequest(stringRequest);
	break;
	case 'check_suite':
	final CheckSuiteEvent checkSuiteEvent = CheckSuiteEvent.fromJson(
	jsonDecode(stringRequest) as Map<String, dynamic>,
	);
	await githubChecksService.handleCheckSuite(
	checkSuiteEvent, luciBuildService);
	break;
	case 'check_run':
	final CheckRunEvent checkRunEvent = CheckRunEvent.fromJson(
	jsonDecode(stringRequest) as Map<String, dynamic>,
	);
	await githubChecksService.handleCheckRun(
	checkRunEvent, luciBuildService);
	}

	return Body.empty;
	} on FormatException {
	throw const BadRequestException('Could not process input data.');
	} on InternalServerError {
	rethrow;
	}
	}

	Future<void> _handlePullRequest(
	String rawRequest,
	) async {
	final PullRequestEvent pullRequestEvent =
	await _getPullRequestEvent(rawRequest);
	if (pullRequestEvent == null) {
	throw const BadRequestException('Expected pull request event.');
	}
	final String eventAction = pullRequestEvent.action;
	final PullRequest pr = pullRequestEvent.pullRequest;

	// See the API reference:
	// https://developer.github.com/v3/activity/events/types/#pullrequestevent
	// which unfortunately is a bit light on explanations.
	switch (eventAction) {
	case 'closed':
	// On a successful merge, check for gold.
	// If it was closed without merging, cancel any outstanding tryjobs.
	// We'll leave unfinished jobs if it was merged since we care about those
	// results.
	if (pr.merged) {
	await _checkForGoldenTriage(pullRequestEvent);
	} else {
	await luciBuildService.cancelBuilds(
	pullRequestEvent.repository.slug(),
	pr.number,
	pr.head.sha,
	'Pull request closed',
	);
	}
	break;
	case 'edited':
	// Editing a PR should not trigger new jobs, but may update whether
	// it has tests.
	await _checkForLabelsAndTests(pullRequestEvent);
	break;
	case 'opened':
	case 'ready_for_review':
	case 'reopened':
	// These cases should trigger LUCI jobs.
	await _checkForLabelsAndTests(pullRequestEvent);
	await _scheduleIfMergeable(pullRequestEvent);
	break;
	case 'labeled':
	// This should only trigger a LUCI job for flutter/flutter right now,
	// since it is in the needsCQLabelList.
	if (kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
	await _scheduleIfMergeable(pullRequestEvent);
	}
	break;
	case 'synchronize':
	// This indicates the PR has new commits. We need to cancel old jobs
	// and schedule new ones.
	await _scheduleIfMergeable(pullRequestEvent);
	break;
	case 'unlabeled':
	// Cancel the jobs if someone removed the label on a repo that needs
	// them.
	if (!kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
	break;
	}
	if (!await _checkForCqLabel(pr.labels)) {
	await luciBuildService.cancelBuilds(
	pullRequestEvent.repository.slug(),
	pr.number,
	pr.head.sha,
	'Tryjobs canceled (label removed)',
	);
	}
	break;
	// Ignore the rest of the events.
	case 'assigned':
	case 'locked':
	case 'review_request_removed':
	case 'review_requested':
	case 'unassigned':
	case 'unlocked':
	break;
	}
	}

	/// This method assumes that jobs should be cancelled if they are already
	/// runnning. [githubStatusService] is used to update the status of a build
	/// in the GitHub UI. When the build is triggered the status is set to "pending"
	/// without a details link. Once the test starts running then the state is set
	/// to "pending" with a details link pointing to the build in LUCI infrastructure.
	Future<void> _scheduleIfMergeable(
	PullRequestEvent pullRequestEvent,
	) async {
	// The mergeable flag may be null. False indicates there's a merge conflict,
	// null indicates unknown. Err on the side of allowing the job to run.
	final PullRequest pr = pullRequestEvent.pullRequest;
	// For flutter/flutter tests need to be optimized before enforcing CQ.
	if (kNeedsCQLabelList.contains(pr.base.repo.fullName.toLowerCase())) {
	if (!await _checkForCqLabel(pr.labels)) {
	return;
	}
	}

	// Always cancel running builds so we don't ever schedule duplicates.
	await luciBuildService.cancelBuilds(
	pullRequestEvent.repository.slug(),
	pr.number,
	pr.head.sha,
	'Newer commit available',
	);
	await luciBuildService.scheduleBuilds(
	slug: pullRequestEvent.repository.slug(),
	prNumber: pr.number,
	commitSha: pr.head.sha,
	);
	await githubStatusService.setBuildsPendingStatus(
	pr.number, pr.head.sha, pr.head.repo.slug());
	}

	/// Checks the issue in the given repository for `config.cqLabelName`.
	Future<bool> _checkForCqLabel(List<IssueLabel> labels) async {
	final String cqLabelName = config.cqLabelName;
	return labels.any((IssueLabel label) => label.name == cqLabelName);
	}

	Future<bool> _isIgnoredForGold(String eventAction, PullRequest pr) async {
	bool ignored = false;
	String rawResponse;
	try {
	final HttpClientRequest request = await skiaClient
	.getUrl(Uri.parse('https://flutter-gold.skia.org/json/ignores'));
	final HttpClientResponse response = await request.close();
	rawResponse = await utf8.decodeStream(response);
	final List<dynamic> ignores = jsonDecode(rawResponse) as List<dynamic>;
	for (Map<String, dynamic> ignore
	in ignores.cast<Map<String, dynamic>>()) {
	if ((ignore['note'] as String).isNotEmpty &&
	pr.number.toString() == ignore['note'].split('/').last) {
	ignored = true;
	break;
	}
	}
	} on IOException catch (e) {
	log.error('Request to Flutter Gold for ignores failed for PR '
	'#${pr.number} on action: $eventAction.\n'
	'error: $e');
	} on FormatException catch (_) {
	log.error('Format Exception from Flutter Gold ignore request.\n'
	'rawResponse: $rawResponse');
	rethrow;
	}
	return ignored;
	}

	Future<void> _checkForGoldenTriage(PullRequestEvent pullRequestEvent) async {
	final PullRequest pr = pullRequestEvent.pullRequest;
	final String eventAction = pullRequestEvent.action;
	final RepositorySlug slug = pullRequestEvent.repository.slug();
	if (kNeedsCheckGoldenTriage.contains(pr.base.repo.fullName.toLowerCase()) &&
	await _isIgnoredForGold(eventAction, pr)) {
	final GitHub gitHubClient =
	await config.createGitHubClient(slug.owner, slug.name);
	try {
	await _pingForTriage(gitHubClient, pr);
	} finally {
	gitHubClient.dispose();
	}
	}
	}

	Future<void> _pingForTriage(GitHub gitHubClient, PullRequest pr) async {
	final String body = config.goldenTriageMessage;
	final RepositorySlug slug = pr.base.repo.slug();
	await gitHubClient.issues.createComment(slug, pr.number, body);
	}

	Future<void> _checkForLabelsAndTests(
	PullRequestEvent pullRequestEvent) async {
	final PullRequest pr = pullRequestEvent.pullRequest;
	final String eventAction = pullRequestEvent.action;
	final RepositorySlug slug = pullRequestEvent.repository.slug();
	final String repo = pr.base.repo.fullName.toLowerCase();
	if (kNeedsCheckLabelsAndTests.contains(repo)) {
	final GitHub gitHubClient =
	await config.createGitHubClient(slug.owner, slug.name);
	try {
	await _checkBaseRef(gitHubClient, pr);
	if (repo == 'flutter/flutter') {
	await _applyFrameworkRepoLabels(gitHubClient, eventAction, pr);
	} else if (repo == 'flutter/engine') {
	await _applyEngineRepoLabels(gitHubClient, eventAction, pr);
	}
	} finally {
	gitHubClient.dispose();
	}
	}
	}

	Future<void> _applyFrameworkRepoLabels(
	GitHub gitHubClient, String eventAction, PullRequest pr) async {
	if (pr.user.login == 'engine-flutter-autoroll') {
	return;
	}
	final RepositorySlug slug = pr.base.repo.slug();
	final Stream<PullRequestFile> files =
	gitHubClient.pullRequests.listFiles(slug, pr.number);
	final Set<String> labels = <String>{};
	bool hasTests = false;
	bool needsTests = false;
	bool isGoldenChange = false;

	await for (PullRequestFile file in files) {
	if (file.filename.endsWith('pubspec.yaml')) {
	// These get updated by a script, and are updated en masse.
	labels.add('team');
	continue;
	}
	if (file.filename.endsWith('.dart')) {
	needsTests = true;
	}
	if (file.filename.endsWith('_test.dart')) {
	hasTests = true;
	}

	if (file.filename.startsWith('dev/')) {
	labels.add('team');
	}
	if (file.filename.startsWith('packages/flutter_tools/') \|\|
	file.filename.startsWith('packages/fuchsia_remote_debug_protocol')) {
	labels.add('tool');
	}
	if (file.filename == 'bin/internal/engine.version') {
	labels.add('engine');
	}
	if (await _isIgnoredForGold(eventAction, pr)) {
	isGoldenChange = true;
	labels.add('will affect goldens');
	labels.add('severe: API break');
	labels.add('a: tests');
	}

	if (file.filename.startsWith('packages/flutter/') \|\|
	file.filename.startsWith('packages/flutter_test/') \|\|
	file.filename.startsWith('packages/flutter_driver/')) {
	labels.add('framework');
	}
	if (file.filename.contains('material')) {
	labels.add('f: material design');
	}
	if (file.filename.contains('cupertino')) {
	labels.add('f: cupertino');
	}

	if (file.filename.startsWith('packages/flutter_localizations')) {
	labels.add('a: internationalization');
	}

	if (file.filename.startsWith('packages/flutter_test') \|\|
	file.filename.startsWith('packages/flutter_driver')) {
	labels.add('a: tests');
	}

	if (file.filename.contains('semantics') \|\|
	file.filename.contains('accessibilty')) {
	labels.add('a: accessibility');
	}

	if (file.filename.startsWith('examples/')) {
	labels.add('d: examples');
	labels.add('team');
	if (file.filename.startsWith('examples/flutter_gallery')) {
	labels.add('team: gallery');
	}
	}
	}

	if (pr.draft) {
	labels.add('work in progress; do not review');
	}

	if (labels.isNotEmpty) {
	await gitHubClient.issues
	.addLabelsToIssue(slug, pr.number, labels.toList());
	}

	if (!hasTests && needsTests && !pr.draft) {
	final String body = config.missingTestsPullRequestMessage;
	if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
	await gitHubClient.issues.createComment(slug, pr.number, body);
	}
	}

	if (isGoldenChange) {
	final String body = config.goldenBreakingChangeMessage;
	if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
	await gitHubClient.issues.createComment(slug, pr.number, body);
	}
	}
	}

	Future<void> _applyEngineRepoLabels(
	GitHub gitHubClient, String eventAction, PullRequest pr) async {
	if (pr.user.login == 'skia-flutter-autoroll') {
	return;
	}
	final RepositorySlug slug = pr.base.repo.slug();
	final Stream<PullRequestFile> files =
	gitHubClient.pullRequests.listFiles(slug, pr.number);
	final Set<String> labels = <String>{};
	bool hasTests = false;
	bool needsTests = false;

	await for (PullRequestFile file in files) {
	final String filename = file.filename.toLowerCase();
	if (filename.endsWith('.dart') \|\|
	filename.endsWith('.mm') \|\|
	filename.endsWith('.m') \|\|
	filename.endsWith('.java') \|\|
	filename.endsWith('.cc')) {
	needsTests = true;
	}

	if (kEngineTestRegExp.hasMatch(filename)) {
	hasTests = true;
	}

	if (filename.startsWith('shell/platform/darwin/ios')) {
	labels.add('platform-ios');
	}

	if (filename.startsWith('shell/platform/android')) {
	labels.add('platform-android');
	}
	}

	if (labels.isNotEmpty) {
	await gitHubClient.issues
	.addLabelsToIssue(slug, pr.number, labels.toList());
	}

	if (!hasTests && needsTests && !pr.draft) {
	final String body = config.missingTestsPullRequestMessage;
	if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
	await gitHubClient.issues.createComment(slug, pr.number, body);
	}
	}
	}

	Future<void> _checkBaseRef(
	GitHub gitHubClient,
	PullRequest pr,
	) async {
	if (pr.base.ref != 'master') {
	final String body = await _getWrongBaseComment(pr.base.ref);
	final RepositorySlug slug = pr.base.repo.slug();
	if (!await _alreadyCommented(gitHubClient, pr, slug, body)) {
	await gitHubClient.pullRequests.edit(
	slug,
	pr.number,
	base: 'master',
	);
	await gitHubClient.issues.createComment(slug, pr.number, body);
	}
	}
	}

	Future<bool> _alreadyCommented(
	GitHub gitHubClient,
	PullRequest pr,
	RepositorySlug slug,
	String message,
	) async {
	final Stream<IssueComment> comments =
	gitHubClient.issues.listCommentsByIssue(slug, pr.number);
	await for (IssueComment comment in comments) {
	if (comment.body.contains(message)) {
	return true;
	}
	}
	return false;
	}

	Future<String> _getWrongBaseComment(String base) async {
	final String messageTemplate = config.nonMasterPullRequestMessage;
	return messageTemplate.replaceAll('{{branch}}', base);
	}

	Future<bool> _validateRequest(
	String signature,
	List<int> requestBody,
	) async {
	final String rawKey = await config.webhookKey;
	final List<int> key = utf8.encode(rawKey);
	final Hmac hmac = Hmac(sha1, key);
	final Digest digest = hmac.convert(requestBody);
	final String bodySignature = 'sha1=$digest';
	return bodySignature == signature;
	}

	Future<PullRequestEvent> _getPullRequestEvent(String request) async {
	if (request == null) {
	return null;
	}
	try {
	return PullRequestEvent.fromJson(
	json.decode(request) as Map<String, dynamic>);
	} on FormatException {
	return null;
	}
	}
	}