Flutter attach (#18677)

Add `flutter attach` command.

This command allows Flutter to connect to applications that haven't been launched using `flutter run`.

dev/devicelab/bin/tasks/flutter_attach_test.dart

@@ -0,0 +1,145 @@
+// Copyright (c) 2018 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';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:path/path.dart' as path;
+import 'package:flutter_devicelab/framework/adb.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/framework/utils.dart';
+
+Future<void> testReload(Process process, { Future<void> Function() onListening }) async {
+  section('Testing hot reload, restart and quit');
+  final Completer<Null> listening = new Completer<Null>();
+  final Completer<Null> ready = new Completer<Null>();
+  final Completer<Null> reloaded = new Completer<Null>();
+  final Completer<Null> restarted = new Completer<Null>();
+  final Completer<Null> finished = new Completer<Null>();
+  final List<String> stdout = <String>[];
+  final List<String> stderr = <String>[];
+
+  if (onListening == null)
+    listening.complete();
+
+  int exitCode;
+  process.stdout
+      .transform(utf8.decoder)
+      .transform(const LineSplitter())
+      .listen((String line) {
+    print('attach:stdout: $line');
+    stdout.add(line);
+    if (line.contains('Listening') && onListening != null) {
+      listening.complete(onListening());
+    }
+    if (line.contains('To quit, press "q".'))
+      ready.complete();
+    if (line.contains('Reloaded '))
+      reloaded.complete();
+    if (line.contains('Restarted app in '))
+      restarted.complete();
+    if (line.contains('Application finished'))
+      finished.complete();
+  });
+  process.stderr
+      .transform(utf8.decoder)
+      .transform(const LineSplitter())
+      .listen((String line) {
+    print('run:stderr: $line');
+    stdout.add(line);
+  });
+
+  process.exitCode.then((int processExitCode) { exitCode = processExitCode; });
+
+  Future<dynamic> eventOrExit(Future<Null> event) {
+    return Future.any<dynamic>(<Future<dynamic>>[ event, process.exitCode ]);
+  }
+
+  await eventOrExit(listening.future);
+  await eventOrExit(ready.future);
+
+  if (exitCode != null)
+    throw 'Failed to attach to test app; command unexpected exited, with exit code $exitCode.';
+
+  process.stdin.write('r');
+  process.stdin.flush();
+  await eventOrExit(reloaded.future);
+  process.stdin.write('R');
+  process.stdin.flush();
+  await eventOrExit(restarted.future);
+  process.stdin.write('q');
+  process.stdin.flush();
+  await eventOrExit(finished.future);
+
+  await process.exitCode;
+
+  if (stderr.isNotEmpty)
+    throw 'flutter attach had output on standard error.';
+
+  if (exitCode != 0)
+    throw 'exit code was not 0';
+}
+
+void main() {
+  const String kAppId = 'com.yourcompany.integration_ui';
+  const String kActivityId = '$kAppId/com.yourcompany.integration_ui.MainActivity';
+
+  task(() async {
+    final AndroidDevice device = await devices.workingDevice;
+    await device.unlock();
+    final Directory appDir = dir(path.join(flutterDirectory.path, 'dev/integration_tests/ui'));
+    await inDirectory(appDir, () async {
+      section('Build: starting...');
+      final String buildStdout = await eval(
+          path.join(flutterDirectory.path, 'bin', 'flutter'),
+          <String>['--suppress-analytics', 'build', 'apk', '--debug', 'lib/main.dart'],
+      );
+      final String lastLine = buildStdout.split('\n').last;
+      final RegExp builtRegExp = new RegExp(r'Built (.+)( \(|\.$)');
+      final String apkPath = builtRegExp.firstMatch(lastLine)[1];
+
+      section('Installing $apkPath');
+
+      await device.adb(<String>['install', apkPath]);
+
+      try {
+        section('Launching attach.');
+        Process attachProcess = await startProcess(
+          path.join(flutterDirectory.path, 'bin', 'flutter'),
+          <String>['--suppress-analytics', 'attach', '-d', device.deviceId],
+          isBot: false, // we just want to test the output, not have any debugging info
+        );
+
+        await testReload(attachProcess, onListening: () async {
+          section('Launching app.');
+          await device.shellExec('am', <String>['start', '-n', kActivityId]);
+        });
+
+        final String currentTime = (await device.shellEval('date', <String>['"+%F %R:%S.000"'])).trim();
+        print('Start time on device: $currentTime');
+        section('Launching app');
+        await device.shellExec('am', <String>['start', '-n', kActivityId]);
+
+        final String observatoryLine = await device.adb(<String>['logcat', '-e', 'Observatory listening on http:', '-m', '1', '-T', currentTime]);
+        print('Found observatory line: $observatoryLine');
+        final String observatoryPort = new RegExp(r'Observatory listening on http://.*:([0-9]+)').firstMatch(observatoryLine)[1];
+        print('Extracted observatory port: $observatoryPort');
+
+        section('Launching attach with given port.');
+        attachProcess = await startProcess(
+          path.join(flutterDirectory.path, 'bin', 'flutter'),
+          <String>['--suppress-analytics', 'attach', '--debug-port', observatoryPort, '-d', device.deviceId],
+          isBot: false, // we just want to test the output, not have any debugging info
+        );
+        await testReload(attachProcess);
+
+      } finally {
+        section('Uninstalling');
+        await device.adb(<String>['uninstall', kAppId]);
+      }
+    });
+    return new TaskResult.success(null);
+  });
+}

dev/devicelab/lib/framework/adb.dart

@@ -248,12 +248,17 @@ class AndroidDevice implements Device {
 
   /// Executes [command] on `adb shell` and returns its exit code.
   Future<Null> shellExec(String command, List<String> arguments, { Map<String, String> environment }) async {
-    await exec(adbPath, <String>['shell', command]..addAll(arguments), environment: environment, canFail: false);
+    await adb(<String>['shell', command]..addAll(arguments), environment: environment);
   }
 
   /// Executes [command] on `adb shell` and returns its standard output as a [String].
   Future<String> shellEval(String command, List<String> arguments, { Map<String, String> environment }) {
-    return eval(adbPath, <String>['shell', command]..addAll(arguments), environment: environment, canFail: false);
+    return adb(<String>['shell', command]..addAll(arguments), environment: environment);
+  }
+
+  /// Runs `adb` with the given [arguments], selecting this device.
+  Future<String> adb(List<String> arguments, { Map<String, String> environment }) {
+    return eval(adbPath, <String>['-s', deviceId]..addAll(arguments), environment: environment, canFail: false);
   }
 
   @override

dev/devicelab/manifest.yaml

@@ -269,6 +269,12 @@ tasks:
     stage: devicelab
     required_agent_capabilities: ["linux/android"]
 
+  flutter_attach_test:
+    description: >
+      Tests the `flutter attach` command.
+    stage: devicelab
+    required_agent_capabilities: ["linux/android"]
+
   # iOS on-device tests
 
   flavors_test_ios: