/
server.dart
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/
server.dart
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// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
// for details. 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:build_daemon/data/server_log.dart';
import 'package:built_value/serializer.dart';
import 'package:http_multi_server/http_multi_server.dart';
import 'package:pool/pool.dart';
import 'package:shelf/shelf_io.dart';
import 'package:shelf_web_socket/shelf_web_socket.dart';
import 'package:stream_transform/stream_transform.dart';
import 'package:watcher/watcher.dart';
import 'package:web_socket_channel/web_socket_channel.dart';
import '../change_provider.dart';
import '../constants.dart';
import '../daemon_builder.dart';
import '../data/build_request.dart';
import '../data/build_target.dart';
import '../data/build_target_request.dart';
import '../data/serializers.dart';
import '../data/shutdown_notification.dart';
import 'managers/build_target_manager.dart';
/// A server which communicates with build daemon clients over websockets.
///
/// Handles notifying clients of logs and results for registered build targets.
/// Note the server will only notify clients of pertinent events.
class Server {
static final loggerName = 'BuildDaemonServer';
final _isDoneCompleter = Completer<int>();
final BuildTargetManager _buildTargetManager;
final _pool = Pool(1);
final Serializers _serializers;
final ChangeProvider _changeProvider;
late final Timer _timeout;
HttpServer? _server;
final DaemonBuilder _builder;
// Channels that are interested in the current build.
var _interestedChannels = <WebSocketChannel>{};
final _subs = <StreamSubscription>[];
final _outputStreamController = StreamController<ServerLog>();
late final Stream<ServerLog> _logs;
Server(
this._builder,
Duration timeout,
ChangeProvider changeProvider, {
Serializers? serializersOverride,
bool Function(BuildTarget, Iterable<WatchEvent>)? shouldBuild,
}) : _changeProvider = changeProvider,
_serializers = serializersOverride ?? serializers,
_buildTargetManager =
BuildTargetManager(shouldBuildOverride: shouldBuild) {
_logs = _outputStreamController.stream;
_forwardData();
_handleChanges(changeProvider.changes);
// Stop the server if nobody connects.
_timeout = Timer(timeout, () async {
if (_buildTargetManager.isEmpty) {
await stop();
}
});
}
/// Returns exit code.
Future<int> get onDone => _isDoneCompleter.future;
/// Starts listening for build daemon clients.
Future<int> listen() async {
var handler = webSocketHandler((WebSocketChannel channel) async {
channel.stream.listen((message) async {
dynamic request;
try {
request = _serializers.deserialize(jsonDecode(message as String));
} catch (e, s) {
_logMessage(Level.WARNING, 'Unable to parse message: $message', e, s);
return;
}
if (request is BuildTargetRequest) {
_buildTargetManager.addBuildTarget(request.target, channel);
} else if (request is BuildRequest) {
var changes = await _changeProvider.collectChanges();
var targets = changes.isEmpty
? _buildTargetManager.targets
: _buildTargetManager.targetsForChanges(changes);
await _build(targets, changes);
}
}, onDone: () {
_removeChannel(channel);
});
});
var server = _server = await HttpMultiServer.loopback(0);
// Serve requests in an error zone to prevent failures
// when running from another error zone.
runZonedGuarded(() => serveRequests(server, handler), (e, s) {
_logMessage(Level.WARNING, 'Error serving requests', e, s);
});
return server.port;
}
Future<void> stop({String message = '', int failureType = 0}) async {
if (message.isNotEmpty && failureType != 0) {
for (var connection in _buildTargetManager.allChannels) {
connection.sink
.add(jsonEncode(_serializers.serialize(ShutdownNotification((b) => b
..message = message
..failureType = failureType))));
}
}
_timeout.cancel();
await _server?.close(force: true);
await _builder.stop();
for (var sub in _subs) {
await sub.cancel();
}
await _outputStreamController.close();
if (!_isDoneCompleter.isCompleted) _isDoneCompleter.complete(failureType);
}
Future<void> _build(
Set<BuildTarget> buildTargets, Iterable<WatchEvent> changes) =>
_pool.withResource(() {
_interestedChannels =
buildTargets.expand(_buildTargetManager.channels).toSet();
return _builder.build(buildTargets, changes);
});
void _forwardData() {
_subs
..add(_builder.logs.listen((log) {
var message = jsonEncode(_serializers.serialize(log));
for (var channel in _interestedChannels) {
channel.sink.add(message);
}
}))
..add(_builder.builds.listen((status) {
// Don't serialize or send changed assets if the client isn't interested
// in them.
String? message, messageWithoutChangedAssets;
for (var channel in _interestedChannels) {
var targets = _buildTargetManager.targetsFor(channel);
var wantsChangedAssets = targets
.any((e) => e is DefaultBuildTarget && e.reportChangedAssets);
String messageForChannel;
if (wantsChangedAssets) {
messageForChannel =
message ??= jsonEncode(_serializers.serialize(status));
} else {
messageForChannel = messageWithoutChangedAssets ??= jsonEncode(
_serializers
.serialize(status.rebuild((b) => b.changedAssets = null)));
}
channel.sink.add(messageForChannel);
}
}))
..add(_logs.listen((log) {
var message = jsonEncode(_serializers.serialize(log));
for (var channel in _interestedChannels) {
channel.sink.add(message);
}
}));
}
void _handleChanges(Stream<List<WatchEvent>> changes) {
_subs.add(changes.asyncMapBuffer((changesLists) async {
var changes = changesLists.expand((x) => x).toList();
if (changes.isEmpty) return;
if (_buildTargetManager.targets.isEmpty) return;
var buildTargets = _buildTargetManager.targetsForChanges(changes);
if (buildTargets.isEmpty) return;
await _build(buildTargets, changes);
}).listen((_) {}, onError: (e) {
stop(
message: 'Error in file change event: $e',
failureType: fileChangeEventErrorCode);
}, onDone: () {
stop(
message: 'File change stream closed',
failureType: fileChangeStreamClosedErrorCode);
}));
}
void _removeChannel(WebSocketChannel channel) async {
_buildTargetManager.removeChannel(channel);
if (_buildTargetManager.isEmpty) {
await stop();
}
}
void _logMessage(Level level, String message,
[Object? error, StackTrace? stackTrace]) =>
_outputStreamController.add(ServerLog((b) => b
..message = message
..level = level
..loggerName = loggerName
..error = error?.toString()
..stackTrace = stackTrace?.toString()));
}