Add appengine/gcloud/mustache dependencies.

pkg/appengine/lib/src/api_impl/logging_impl.dart

+// Copyright (c) 2014, 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.
+
+library appengine.logging_impl;
+
+import 'dart:async';
+
+import 'package:fixnum/fixnum.dart';
+import 'package:appengine/api/logging.dart';
+
+import '../protobuf_api/rpc/rpc_service.dart';
+import '../protobuf_api/logging_service.dart';
+import '../protobuf_api/internal/log_service.pb.dart' as pb;
+
+class LoggingRpcImpl extends Logging {
+  final LoggingServiceClientRPCStub _clientRPCStub;
+  final List<pb.UserAppLogLine> _logLines = <pb.UserAppLogLine>[];
+
+  LoggingRpcImpl(RPCService rpcService, String ticket)
+      : _clientRPCStub = new LoggingServiceClientRPCStub(rpcService, ticket);
+
+  void log(LogLevel level, String message, {DateTime timestamp}) {
+    if (timestamp == null) {
+      timestamp = new DateTime.now();
+    }
+
+    // Issue 15747158.
+    print('$timestamp: ApplicationLog | $level: ${message.trim()}');
+
+    _logLines.add(_createLogLine(level, message, timestamp));
+  }
+
+  pb.UserAppLogLine _createLogLine(
+      LogLevel level, String message, DateTime timestamp) {
+    var timestampUsec = timestamp.toUtc().millisecondsSinceEpoch * 1000;
+    return new pb.UserAppLogLine()
+        ..timestampUsec = new Int64(timestampUsec)
+        ..level = new Int64(level.level)
+        ..message = message;
+  }
+
+  Future flush() {
+    if (_logLines.isEmpty) {
+      return new Future.value();
+    }
+
+    var group = new pb.UserAppLogGroup();
+    group.logLine.addAll(_logLines);
+    _logLines.clear();
+
+    var request = new pb.FlushRequest()
+        ..logs = group.writeToBuffer();
+
+    // NOTE: We swallow errors here to prevent clients sending error messages
+    // using the logging service -- which would create an infinite error loop.
+    // TODO: We could introduce a local logging mechanism in the future which
+    // we could use to report such errors.
+    return _clientRPCStub.Flush(request).catchError((_) {}).then((_) => null);
+  }
+}