logs.dart 2.24 KB
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// Copyright 2015 The Chromium 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';

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import '../base/common.dart';
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import '../base/io.dart';
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import '../cache.dart';
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import '../device.dart';
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import '../globals.dart';
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import '../runner/flutter_command.dart';
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class LogsCommand extends FlutterCommand {
  LogsCommand() {
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    argParser.addFlag('clear',
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      negatable: false,
      abbr: 'c',
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      help: 'Clear log history before reading from logs.',
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    );
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  }

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  @override
  final String name = 'logs';

  @override
  final String description = 'Show log output for running Flutter apps.';

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  @override
  Future<Set<DevelopmentArtifact>> get requiredArtifacts async => const <DevelopmentArtifact>{};

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  Device device;
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  @override
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  Future<FlutterCommandResult> verifyThenRunCommand(String commandPath) async {
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    device = await findTargetDevice();
    if (device == null)
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      throwToolExit(null);
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    return super.verifyThenRunCommand(commandPath);
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  }
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  @override
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  Future<FlutterCommandResult> runCommand() async {
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    if (argResults['clear'])
      device.clearLogs();
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    final DeviceLogReader logReader = device.getLogReader();
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    Cache.releaseLockEarly();

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    printStatus('Showing $logReader logs:');
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    final Completer<int> exitCompleter = Completer<int>();
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    // Start reading.
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    final StreamSubscription<String> subscription = logReader.logLines.listen(
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      (String message) => printStatus(message, wrap: false),
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      onDone: () {
        exitCompleter.complete(0);
      },
      onError: (dynamic error) {
        exitCompleter.complete(error is int ? error : 1);
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      },
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    );
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    // When terminating, close down the log reader.
    ProcessSignal.SIGINT.watch().listen((ProcessSignal signal) {
      subscription.cancel();
      printStatus('');
      exitCompleter.complete(0);
    });
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    ProcessSignal.SIGTERM.watch().listen((ProcessSignal signal) {
      subscription.cancel();
      exitCompleter.complete(0);
    });
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    // Wait for the log reader to be finished.
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    final int result = await exitCompleter.future;
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    await subscription.cancel();
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    if (result != 0)
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      throwToolExit('Error listening to $logReader logs.');
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    return null;
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  }
}