tool/lib/commands/serve.dart - external/github.com/flutter/devtools - Git at Google

 // Copyright 2022 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.

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

 import 'package:args/command_runner.dart';
 import 'package:devtools_tool/model.dart';
 import 'package:devtools_tool/utils.dart';
 import 'package:io/io.dart';
 import 'package:path/path.dart' as path;

 import 'shared.dart';

 const _buildAppFlag = 'build-app';

 // TODO(https://github.com/flutter/devtools/issues/7232): Consider using
 // AllowAnythingParser instead of manually passing these args through.
 const _machineFlag = 'machine';
 const _dtdUriFlag = 'dtd-uri';
 const _allowEmbeddingFlag = 'allow-embedding';

 /// This command builds DevTools in release mode by running the
 /// `dt build` command and then serves DevTools with a locally
 /// running DevTools server.
 ///
 /// If the [_buildAppFlag] argument is negated (e.g. --no-build-app), then the
 /// DevTools web app will not be rebuilt before serving. The following arguments
 /// are ignored if '--no-build-app' is present in the list of arguments passed
 /// to this command. All of the following commands are passed along to the
 /// `dt build` command.
 ///
 /// If the [SharedCommandArgs.runApp] argument is passed (e.g. --run-app), then
 /// DevTools will be run with `flutter run` instead of being built with
 /// `flutter build web`. The DevTools web app running from Flutter Tool will be
 /// connected to a locally running instance of the DevTools server.
 ///
 /// If the [SharedCommandArgs.debugServer] argument is present, the DevTools
 /// server will be started with the `--observe` flag. This will allow you to
 /// debug and profile the server with a local VM service connection. By default,
 /// this will set `--pause-isolates-on-start` and
 /// `--pause-isolates-on-unhandled-exceptions` for the DevTools server VM
 /// service connection.
 ///
 /// If the [SharedCommandArgs.useFlutterFromPath] argument is present, the
 /// Flutter SDK will not be updated to the latest Flutter candidate before
 /// building DevTools. Use this flag to save the cost of updating the Flutter
 /// SDK when you already have the proper SDK checked out. This is helpful when
 /// developing with the DevTools server.
 ///
 /// If the [SharedCommandArgs.updatePerfetto] argument is present, the
 /// precompiled bits for Perfetto will be updated from the
 /// `dt update-perfetto` command as part of the DevTools build
 /// process.
 ///
 /// If [SharedCommandArgs.pubGet] argument is negated (e.g. --no-pub-get), then
 /// `dt pub-get --only-main` command will not be run before building
 /// the DevTools web app. Use this flag to save the cost of updating pub
 /// packages if your pub cahce does not need to be updated. This is helpful when
 /// developing with the DevTools server.
 ///
 /// The [SharedCommandArgs.buildMode] argument specifies the Flutter build mode
 /// that the DevTools web app will be built in ('release', 'profile', 'debug').
 /// This defaults to 'release' if unspecified.
 class ServeCommand extends Command {
   ServeCommand() {
     argParser
       ..addFlag(
         _buildAppFlag,
         negatable: true,
         defaultsTo: true,
         help:
             'Whether to build the DevTools web app before starting the DevTools'
             ' server. If --no-build-app is passed, the existing assets from'
             ' devtools_app/build/web will be used.',
       )
       ..addFlag(
         SharedCommandArgs.runApp.flagName,
         negatable: false,
         defaultsTo: false,
         help:
             'Whether to run the DevTools web app using `flutter run` instead'
             ' of building it using `flutter build web` and serving the assets'
             ' directly from the DevTools server.',
       )
       ..addDebugServerFlag()
       ..addServeWithSdkOption()
       ..addUpdateFlutterFlag()
       ..addUpdatePerfettoFlag()
       ..addPubGetFlag()
       ..addBulidModeOption()
       ..addWasmFlag()
       ..addNoStripWasmFlag()
       ..addNoMinifyWasmFlag()
       // Flags defined in the server in DDS.
       ..addFlag(
         _machineFlag,
         negatable: false,
         help: 'Sets output format to JSON for consumption in tools.',
       )
       ..addOption(
         _dtdUriFlag,
         help: 'Sets the dtd uri when starting the devtools server',
       )
       ..addFlag(
         _allowEmbeddingFlag,
         help: 'Allow embedding DevTools inside an iframe.',
       );
   }

   static const _devToolsServerAddressLine = 'Serving DevTools at ';
   static const _debugServerVmServiceLine =
       'The Dart VM service is listening on ';
   static const _debugServerDartDevToolsLine =
       'The Dart DevTools debugger and profiler is available at: ';
   static const _runAppVmServiceLine =
       'A Dart VM Service on Chrome is available at: ';
   static const _runAppFlutterDevToolsLine =
       'The Flutter DevTools debugger and profiler on Chrome is available at: ';

   @override
   String get name => 'serve';

   @override
   String get description =>
       'Builds DevTools in release mode and serves the web app with a locally '
       'running DevTools server.';

   @override
   Future run() async {
     logStatus(
       'WARNING: if you have local changes in packages/devtools_shared, you will'
       ' need to add a path dependency override in sdk/pkg/dds/pubspec.yaml in'
       ' order for these changes to be picked up.',
     );

     final repo = DevToolsRepo.getInstance();
     final processManager = ProcessManager();

     final results = argResults!;
     final buildApp = results[_buildAppFlag] as bool;
     final runApp = results[SharedCommandArgs.runApp.flagName] as bool;
     final debugServer = results[SharedCommandArgs.debugServer.flagName] as bool;
     final updateFlutter =
         results[SharedCommandArgs.updateFlutter.flagName] as bool;
     final updatePerfetto =
         results[SharedCommandArgs.updatePerfetto.flagName] as bool;
     final useWasm = results[SharedCommandArgs.wasm.flagName] as bool;
     final noStripWasm = results[SharedCommandArgs.noStripWasm.flagName] as bool;
     final noMinifyWasm = results[SharedCommandArgs.noMinifyWasm.flagName] as bool;
     final runPubGet = results[SharedCommandArgs.pubGet.flagName] as bool;
     final devToolsAppBuildMode =
         results[SharedCommandArgs.buildMode.flagName] as String;
     final serveWithDartSdk =
         results[SharedCommandArgs.serveWithDartSdk.flagName] as String?;
     final forMachine = results[_machineFlag] as bool;

     // TODO(https://github.com/flutter/devtools/issues/8643): Support running in
     // machine mode with a debuggable DevTools app.
     if (runApp && forMachine) {
       throw Exception(
         'Machine mode is not supported with `flutter run` DevTools.\n'
         'Please use either --machine or --run-app, not both.\n'
         'See https://github.com/flutter/devtools/issues/8643 for details.',
       );
     }

     // Any flag that we aren't removing here is intended to be passed through.
     final remainingArguments =
         List.of(results.arguments)
           ..remove(SharedCommandArgs.updateFlutter.asArg())
           ..remove(SharedCommandArgs.updateFlutter.asArg(negated: true))
           ..remove(SharedCommandArgs.updatePerfetto.asArg())
           ..remove(SharedCommandArgs.wasm.asArg())
           ..remove(SharedCommandArgs.noStripWasm.asArg())
           ..remove(SharedCommandArgs.noMinifyWasm.asArg())
           ..remove(valueAsArg(_buildAppFlag))
           ..remove(valueAsArg(_buildAppFlag, negated: true))
           ..remove(SharedCommandArgs.runApp.asArg())
           ..remove(SharedCommandArgs.debugServer.asArg())
           ..remove(SharedCommandArgs.pubGet.asArg())
           ..remove(SharedCommandArgs.pubGet.asArg(negated: true))
           ..removeWhere(
             (element) =>
                 element.startsWith(SharedCommandArgs.buildMode.asArg()),
           )
           ..removeWhere(
             (element) => element.startsWith(
               valueAsArg(SharedCommandArgs.serveWithDartSdk.flagName),
             ),
           );

     final localDartSdkLocation = Platform.environment['LOCAL_DART_SDK'];
     if (localDartSdkLocation == null) {
       throw Exception(
         'LOCAL_DART_SDK environment variable not set. Please add '
         'the following to your \'.bash_profile\' or \'.bashrc\' file:\n'
         'export LOCAL_DART_SDK=<absolute/path/to/my/sdk>',
       );
     }

     // Validate the path looks correct in case it was set without the /sdk or
     // similar.
     final pkgDir = Directory(path.join(localDartSdkLocation, 'pkg'));
     if (!pkgDir.existsSync()) {
       throw Exception(
         'No pkg directory found in LOCAL_DART_SDK at "${pkgDir.path}"\n'
         'Is LOCAL_DART_SDK set correctly to the "sdk" directory?',
       );
     }

     final devToolsBuildLocation = path.join(
       repo.devtoolsAppDirectoryPath,
       'build',
       'web',
     );

     if (buildApp && !runApp) {
       final process = await processManager.runProcess(
         CliCommand.tool([
           'build',
           SharedCommandArgs.updateFlutter.asArg(negated: !updateFlutter),
           if (updatePerfetto) SharedCommandArgs.updatePerfetto.asArg(),
           if (useWasm) SharedCommandArgs.wasm.asArg(),
           if (noStripWasm) SharedCommandArgs.noStripWasm.asArg(),
           if (noMinifyWasm) SharedCommandArgs.noMinifyWasm.asArg(),
           '${SharedCommandArgs.buildMode.asArg()}=$devToolsAppBuildMode',
           SharedCommandArgs.pubGet.asArg(negated: !runPubGet),
         ]),
       );
       if (process.exitCode == 1) {
         throw Exception('Something went wrong while running `dt build`');
       }
       logStatus('completed building DevTools: $devToolsBuildLocation');
     }

     logStatus('running pub get for DDS in the local dart sdk');
     await processManager.runProcess(
       CliCommand.dart(['pub', 'get']),
       workingDirectory: path.join(localDartSdkLocation, 'pkg', 'dds'),
     );

     logStatus('serving DevTools with a local devtools server...');
     final ddsServeLocalScriptPath = path.join(
       'pkg',
       'dds',
       'tool',
       'devtools_server',
       'serve_local.dart',
     );

     // The address of the locally running DevTools server.
     String? devToolsServerAddress;

     // This is the DevTools URI associated with the DevTools server process
     // when the '--debug-server' flag is present. This DevTools connection
     // allows you to debug the DevTools server logic.
     String? debugServerDevToolsConnection;

     // This is the VM Service URI associated with the DevTools server process
     // when the '--debug-server' flag is present.
     String? debugServerVmServiceUri;

     void processServeLocalOutput(String line) {
       if (line.startsWith(_debugServerVmServiceLine)) {
         debugServerVmServiceUri =
             line.substring(_debugServerVmServiceLine.length).trim();
       } else if (line.startsWith(_debugServerDartDevToolsLine)) {
         debugServerDevToolsConnection =
             line.substring(_debugServerDartDevToolsLine.length).trim();
       } else if (line.startsWith(_devToolsServerAddressLine)) {
         // This will pull the server address from a String like:
         // "Serving DevTools at http://127.0.0.1:9104.".
         final regexp = RegExp(
           r'http:\/\/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:\d+',
         );
         final match = regexp.firstMatch(line);
         if (match != null) {
           devToolsServerAddress = match.group(0);
         }
       }
     }

     // This call will not exit until explicitly terminated by the user.
     final cliCommand = CliCommand.dart([
       if (debugServer) ...['run', '--observe=0'],
       ddsServeLocalScriptPath,
       if (runApp)
         // When running DevTools via `flutter run`, the [flutterRunProcess]
         // below will launch DevTools in the browser.
         '--no-launch-browser'
       else
         // Only pass a build location if the server is serving the web assets
         // (i.e. not when DevTools app is ran via `flutter run`).
         '--devtools-build=$devToolsBuildLocation',
       // Pass any args that were provided to our script along. This allows IDEs
       // to pass `--machine` (etc.) so that this script can behave the same as
       // the "dart devtools" command for testing local DevTools/server changes.
       ...remainingArguments,
     ], sdkOverride: serveWithDartSdk);
     if (forMachine) {
       // If --machine flag is true, then the output is a tool-readable JSON.
       // Therefore, skip reading the process output and instead just run the
       // process.
       return processManager.runProcess(
         cliCommand,
         workingDirectory: localDartSdkLocation,
       );
     }

     final serveLocalProcess = await startIndependentProcess(
       cliCommand,
       workingDirectory: localDartSdkLocation,
       waitForOutput: _devToolsServerAddressLine,
       onOutput: processServeLocalOutput,
     );

     Process? flutterRunProcess;
     if (runApp) {
       if (devToolsServerAddress == null) {
         await _killProcess(serveLocalProcess);
         throw Exception(
           'Cannot run DevTools and connect to the DevTools server because '
           'devToolsServerAddress is null.',
         );
       }

       // This is the DevTools URI associated with the DevTools web app when it is
       // run using `flutter run` (e.g. when [runApp] is true).
       String? devToolsWebAppDevToolsConnection;

       // This is the VM service URI associated with the DevTools web app when it
       // is run using `flutter run` (e.g. when [runApp] is true).
       String? devToolsWebAppVmServiceUri;

       void processFlutterRunOutput(String line) {
         if (line.contains(_runAppVmServiceLine)) {
           final index = line.indexOf(_runAppVmServiceLine);
           devToolsWebAppVmServiceUri =
               line.substring(index + _runAppVmServiceLine.length).trim();
         } else if (line.contains(_runAppFlutterDevToolsLine)) {
           final index = line.indexOf(_runAppFlutterDevToolsLine);
           devToolsWebAppDevToolsConnection =
               line.substring(index + _runAppFlutterDevToolsLine.length).trim();
         }
       }

       logStatus('running DevTools');
       flutterRunProcess = await startIndependentProcess(
         CliCommand.flutter([
           'run',
           '-d',
           'chrome',
           // TODO(https://github.com/flutter/flutter/issues/160130):
           //  [flutterRunProcess] exits without the --verbose flag.
           '--verbose',
           // Add the trailing slash because this is what DevTools app expects.
           '--dart-define=debug_devtools_server=$devToolsServerAddress/',
         ]),
         workingDirectory: repo.devtoolsAppDirectoryPath,
         waitForOutput: _runAppFlutterDevToolsLine,
         onOutput: processFlutterRunOutput,
       );

       // Consolidate important stdout content for easy access.
       final debugServerContent =
           debugServer
               ? '''
 - VM Service URI: $debugServerVmServiceUri
 - DevTools URI for debugging the DevTools server: $debugServerDevToolsConnection
 '''
               : '';

       print('''
 -------------------------------------------------------------------

 The DevTools web app should have just launched on Chrome.
 - VM Service URI: $devToolsWebAppVmServiceUri
 - DevTools URI for debugging the DevTools web app: $devToolsWebAppDevToolsConnection

 The DevTools server is running at: $devToolsServerAddress.
 $debugServerContent
 -------------------------------------------------------------------
 ''');
     }

     await _waitForAndHandleExit(
       serveLocalProcess: serveLocalProcess,
       flutterRunProcess: flutterRunProcess,
     );
   }

   Future<void> _waitForAndHandleExit({
     required Process serveLocalProcess,
     required Process? flutterRunProcess,
   }) async {
     final serveLocalProcessExited = Completer<int>();
     final flutterRunProcessExited = Completer<int>();
     unawaited(
       serveLocalProcess.exitCode.then((code) {
         serveLocalProcessExited.complete(code);
       }),
     );
     if (flutterRunProcess != null) {
       unawaited(
         flutterRunProcess.exitCode.then((code) {
           flutterRunProcessExited.complete(code);
         }),
       );
     }

     await Future.any([
       serveLocalProcessExited.future,
       flutterRunProcessExited.future,
     ]);

     if (serveLocalProcessExited.isCompleted &&
         !flutterRunProcessExited.isCompleted &&
         flutterRunProcess != null) {
       final exitCode = await serveLocalProcessExited.future;
       logStatus(
         'Killing the flutterRunProcess because the serveLocalProcess has '
         'exited with code $exitCode.',
       );
       await _killProcess(flutterRunProcess);
     }

     if (flutterRunProcessExited.isCompleted &&
         !serveLocalProcessExited.isCompleted) {
       final exitCode = await flutterRunProcessExited.future;
       logStatus(
         'Killing the serveLocalProcess because the flutterRunProcess has '
         'exited with code $exitCode.',
       );
       await _killProcess(serveLocalProcess);
     }
   }

   Future<void> _killProcess(Process? process) async {
     if (process != null) {
       Process.killPid(process.pid, ProcessSignal.sigint);
       await process.exitCode;
     }
   }
 }
	// Copyright 2022 The Flutter Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.

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

	import 'package:args/command_runner.dart';
	import 'package:devtools_tool/model.dart';
	import 'package:devtools_tool/utils.dart';
	import 'package:io/io.dart';
	import 'package:path/path.dart' as path;

	import 'shared.dart';

	const _buildAppFlag = 'build-app';

	// TODO(https://github.com/flutter/devtools/issues/7232): Consider using
	// AllowAnythingParser instead of manually passing these args through.
	const _machineFlag = 'machine';
	const _dtdUriFlag = 'dtd-uri';
	const _allowEmbeddingFlag = 'allow-embedding';

	/// This command builds DevTools in release mode by running the
	/// `dt build` command and then serves DevTools with a locally
	/// running DevTools server.
	///
	/// If the [_buildAppFlag] argument is negated (e.g. --no-build-app), then the
	/// DevTools web app will not be rebuilt before serving. The following arguments
	/// are ignored if '--no-build-app' is present in the list of arguments passed
	/// to this command. All of the following commands are passed along to the
	/// `dt build` command.
	///
	/// If the [SharedCommandArgs.runApp] argument is passed (e.g. --run-app), then
	/// DevTools will be run with `flutter run` instead of being built with
	/// `flutter build web`. The DevTools web app running from Flutter Tool will be
	/// connected to a locally running instance of the DevTools server.
	///
	/// If the [SharedCommandArgs.debugServer] argument is present, the DevTools
	/// server will be started with the `--observe` flag. This will allow you to
	/// debug and profile the server with a local VM service connection. By default,
	/// this will set `--pause-isolates-on-start` and
	/// `--pause-isolates-on-unhandled-exceptions` for the DevTools server VM
	/// service connection.
	///
	/// If the [SharedCommandArgs.useFlutterFromPath] argument is present, the
	/// Flutter SDK will not be updated to the latest Flutter candidate before
	/// building DevTools. Use this flag to save the cost of updating the Flutter
	/// SDK when you already have the proper SDK checked out. This is helpful when
	/// developing with the DevTools server.
	///
	/// If the [SharedCommandArgs.updatePerfetto] argument is present, the
	/// precompiled bits for Perfetto will be updated from the
	/// `dt update-perfetto` command as part of the DevTools build
	/// process.
	///
	/// If [SharedCommandArgs.pubGet] argument is negated (e.g. --no-pub-get), then
	/// `dt pub-get --only-main` command will not be run before building
	/// the DevTools web app. Use this flag to save the cost of updating pub
	/// packages if your pub cahce does not need to be updated. This is helpful when
	/// developing with the DevTools server.
	///
	/// The [SharedCommandArgs.buildMode] argument specifies the Flutter build mode
	/// that the DevTools web app will be built in ('release', 'profile', 'debug').
	/// This defaults to 'release' if unspecified.
	class ServeCommand extends Command {
	ServeCommand() {
	argParser
	..addFlag(
	_buildAppFlag,
	negatable: true,
	defaultsTo: true,
	help:
	'Whether to build the DevTools web app before starting the DevTools'
	' server. If --no-build-app is passed, the existing assets from'
	' devtools_app/build/web will be used.',
	)
	..addFlag(
	SharedCommandArgs.runApp.flagName,
	negatable: false,
	defaultsTo: false,
	help:
	'Whether to run the DevTools web app using `flutter run` instead'
	' of building it using `flutter build web` and serving the assets'
	' directly from the DevTools server.',
	)
	..addDebugServerFlag()
	..addServeWithSdkOption()
	..addUpdateFlutterFlag()
	..addUpdatePerfettoFlag()
	..addPubGetFlag()
	..addBulidModeOption()
	..addWasmFlag()
	..addNoStripWasmFlag()
	..addNoMinifyWasmFlag()
	// Flags defined in the server in DDS.
	..addFlag(
	_machineFlag,
	negatable: false,
	help: 'Sets output format to JSON for consumption in tools.',
	)
	..addOption(
	_dtdUriFlag,
	help: 'Sets the dtd uri when starting the devtools server',
	)
	..addFlag(
	_allowEmbeddingFlag,
	help: 'Allow embedding DevTools inside an iframe.',
	);
	}

	static const _devToolsServerAddressLine = 'Serving DevTools at ';
	static const _debugServerVmServiceLine =
	'The Dart VM service is listening on ';
	static const _debugServerDartDevToolsLine =
	'The Dart DevTools debugger and profiler is available at: ';
	static const _runAppVmServiceLine =
	'A Dart VM Service on Chrome is available at: ';
	static const _runAppFlutterDevToolsLine =
	'The Flutter DevTools debugger and profiler on Chrome is available at: ';

	@override
	String get name => 'serve';

	@override
	String get description =>
	'Builds DevTools in release mode and serves the web app with a locally '
	'running DevTools server.';

	@override
	Future run() async {
	logStatus(
	'WARNING: if you have local changes in packages/devtools_shared, you will'
	' need to add a path dependency override in sdk/pkg/dds/pubspec.yaml in'
	' order for these changes to be picked up.',
	);

	final repo = DevToolsRepo.getInstance();
	final processManager = ProcessManager();

	final results = argResults!;
	final buildApp = results[_buildAppFlag] as bool;
	final runApp = results[SharedCommandArgs.runApp.flagName] as bool;
	final debugServer = results[SharedCommandArgs.debugServer.flagName] as bool;
	final updateFlutter =
	results[SharedCommandArgs.updateFlutter.flagName] as bool;
	final updatePerfetto =
	results[SharedCommandArgs.updatePerfetto.flagName] as bool;
	final useWasm = results[SharedCommandArgs.wasm.flagName] as bool;
	final noStripWasm = results[SharedCommandArgs.noStripWasm.flagName] as bool;
	final noMinifyWasm = results[SharedCommandArgs.noMinifyWasm.flagName] as bool;
	final runPubGet = results[SharedCommandArgs.pubGet.flagName] as bool;
	final devToolsAppBuildMode =
	results[SharedCommandArgs.buildMode.flagName] as String;
	final serveWithDartSdk =
	results[SharedCommandArgs.serveWithDartSdk.flagName] as String?;
	final forMachine = results[_machineFlag] as bool;

	// TODO(https://github.com/flutter/devtools/issues/8643): Support running in
	// machine mode with a debuggable DevTools app.
	if (runApp && forMachine) {
	throw Exception(
	'Machine mode is not supported with `flutter run` DevTools.\n'
	'Please use either --machine or --run-app, not both.\n'
	'See https://github.com/flutter/devtools/issues/8643 for details.',
	);
	}

	// Any flag that we aren't removing here is intended to be passed through.
	final remainingArguments =
	List.of(results.arguments)
	..remove(SharedCommandArgs.updateFlutter.asArg())
	..remove(SharedCommandArgs.updateFlutter.asArg(negated: true))
	..remove(SharedCommandArgs.updatePerfetto.asArg())
	..remove(SharedCommandArgs.wasm.asArg())
	..remove(SharedCommandArgs.noStripWasm.asArg())
	..remove(SharedCommandArgs.noMinifyWasm.asArg())
	..remove(valueAsArg(_buildAppFlag))
	..remove(valueAsArg(_buildAppFlag, negated: true))
	..remove(SharedCommandArgs.runApp.asArg())
	..remove(SharedCommandArgs.debugServer.asArg())
	..remove(SharedCommandArgs.pubGet.asArg())
	..remove(SharedCommandArgs.pubGet.asArg(negated: true))
	..removeWhere(
	(element) =>
	element.startsWith(SharedCommandArgs.buildMode.asArg()),
	)
	..removeWhere(
	(element) => element.startsWith(
	valueAsArg(SharedCommandArgs.serveWithDartSdk.flagName),
	),
	);

	final localDartSdkLocation = Platform.environment['LOCAL_DART_SDK'];
	if (localDartSdkLocation == null) {
	throw Exception(
	'LOCAL_DART_SDK environment variable not set. Please add '
	'the following to your \'.bash_profile\' or \'.bashrc\' file:\n'
	'export LOCAL_DART_SDK=<absolute/path/to/my/sdk>',
	);
	}

	// Validate the path looks correct in case it was set without the /sdk or
	// similar.
	final pkgDir = Directory(path.join(localDartSdkLocation, 'pkg'));
	if (!pkgDir.existsSync()) {
	throw Exception(
	'No pkg directory found in LOCAL_DART_SDK at "${pkgDir.path}"\n'
	'Is LOCAL_DART_SDK set correctly to the "sdk" directory?',
	);
	}

	final devToolsBuildLocation = path.join(
	repo.devtoolsAppDirectoryPath,
	'build',
	'web',
	);

	if (buildApp && !runApp) {
	final process = await processManager.runProcess(
	CliCommand.tool([
	'build',
	SharedCommandArgs.updateFlutter.asArg(negated: !updateFlutter),
	if (updatePerfetto) SharedCommandArgs.updatePerfetto.asArg(),
	if (useWasm) SharedCommandArgs.wasm.asArg(),
	if (noStripWasm) SharedCommandArgs.noStripWasm.asArg(),
	if (noMinifyWasm) SharedCommandArgs.noMinifyWasm.asArg(),
	'${SharedCommandArgs.buildMode.asArg()}=$devToolsAppBuildMode',
	SharedCommandArgs.pubGet.asArg(negated: !runPubGet),
	]),
	);
	if (process.exitCode == 1) {
	throw Exception('Something went wrong while running `dt build`');
	}
	logStatus('completed building DevTools: $devToolsBuildLocation');
	}

	logStatus('running pub get for DDS in the local dart sdk');
	await processManager.runProcess(
	CliCommand.dart(['pub', 'get']),
	workingDirectory: path.join(localDartSdkLocation, 'pkg', 'dds'),
	);

	logStatus('serving DevTools with a local devtools server...');
	final ddsServeLocalScriptPath = path.join(
	'pkg',
	'dds',
	'tool',
	'devtools_server',
	'serve_local.dart',
	);

	// The address of the locally running DevTools server.
	String? devToolsServerAddress;

	// This is the DevTools URI associated with the DevTools server process
	// when the '--debug-server' flag is present. This DevTools connection
	// allows you to debug the DevTools server logic.
	String? debugServerDevToolsConnection;

	// This is the VM Service URI associated with the DevTools server process
	// when the '--debug-server' flag is present.
	String? debugServerVmServiceUri;

	void processServeLocalOutput(String line) {
	if (line.startsWith(_debugServerVmServiceLine)) {
	debugServerVmServiceUri =
	line.substring(_debugServerVmServiceLine.length).trim();
	} else if (line.startsWith(_debugServerDartDevToolsLine)) {
	debugServerDevToolsConnection =
	line.substring(_debugServerDartDevToolsLine.length).trim();
	} else if (line.startsWith(_devToolsServerAddressLine)) {
	// This will pull the server address from a String like:
	// "Serving DevTools at http://127.0.0.1:9104.".
	final regexp = RegExp(
	r'http:\/\/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:\d+',
	);
	final match = regexp.firstMatch(line);
	if (match != null) {
	devToolsServerAddress = match.group(0);
	}
	}
	}

	// This call will not exit until explicitly terminated by the user.
	final cliCommand = CliCommand.dart([
	if (debugServer) ...['run', '--observe=0'],
	ddsServeLocalScriptPath,
	if (runApp)
	// When running DevTools via `flutter run`, the [flutterRunProcess]
	// below will launch DevTools in the browser.
	'--no-launch-browser'
	else
	// Only pass a build location if the server is serving the web assets
	// (i.e. not when DevTools app is ran via `flutter run`).
	'--devtools-build=$devToolsBuildLocation',
	// Pass any args that were provided to our script along. This allows IDEs
	// to pass `--machine` (etc.) so that this script can behave the same as
	// the "dart devtools" command for testing local DevTools/server changes.
	...remainingArguments,
	], sdkOverride: serveWithDartSdk);
	if (forMachine) {
	// If --machine flag is true, then the output is a tool-readable JSON.
	// Therefore, skip reading the process output and instead just run the
	// process.
	return processManager.runProcess(
	cliCommand,
	workingDirectory: localDartSdkLocation,
	);
	}

	final serveLocalProcess = await startIndependentProcess(
	cliCommand,
	workingDirectory: localDartSdkLocation,
	waitForOutput: _devToolsServerAddressLine,
	onOutput: processServeLocalOutput,
	);

	Process? flutterRunProcess;
	if (runApp) {
	if (devToolsServerAddress == null) {
	await _killProcess(serveLocalProcess);
	throw Exception(
	'Cannot run DevTools and connect to the DevTools server because '
	'devToolsServerAddress is null.',
	);
	}

	// This is the DevTools URI associated with the DevTools web app when it is
	// run using `flutter run` (e.g. when [runApp] is true).
	String? devToolsWebAppDevToolsConnection;

	// This is the VM service URI associated with the DevTools web app when it
	// is run using `flutter run` (e.g. when [runApp] is true).
	String? devToolsWebAppVmServiceUri;

	void processFlutterRunOutput(String line) {
	if (line.contains(_runAppVmServiceLine)) {
	final index = line.indexOf(_runAppVmServiceLine);
	devToolsWebAppVmServiceUri =
	line.substring(index + _runAppVmServiceLine.length).trim();
	} else if (line.contains(_runAppFlutterDevToolsLine)) {
	final index = line.indexOf(_runAppFlutterDevToolsLine);
	devToolsWebAppDevToolsConnection =
	line.substring(index + _runAppFlutterDevToolsLine.length).trim();
	}
	}

	logStatus('running DevTools');
	flutterRunProcess = await startIndependentProcess(
	CliCommand.flutter([
	'run',
	'-d',
	'chrome',
	// TODO(https://github.com/flutter/flutter/issues/160130):
	// [flutterRunProcess] exits without the --verbose flag.
	'--verbose',
	// Add the trailing slash because this is what DevTools app expects.
	'--dart-define=debug_devtools_server=$devToolsServerAddress/',
	]),
	workingDirectory: repo.devtoolsAppDirectoryPath,
	waitForOutput: _runAppFlutterDevToolsLine,
	onOutput: processFlutterRunOutput,
	);

	// Consolidate important stdout content for easy access.
	final debugServerContent =
	debugServer
	? '''
	- VM Service URI: $debugServerVmServiceUri
	- DevTools URI for debugging the DevTools server: $debugServerDevToolsConnection
	'''
	: '';

	print('''
	-------------------------------------------------------------------

	The DevTools web app should have just launched on Chrome.
	- VM Service URI: $devToolsWebAppVmServiceUri
	- DevTools URI for debugging the DevTools web app: $devToolsWebAppDevToolsConnection

	The DevTools server is running at: $devToolsServerAddress.
	$debugServerContent
	-------------------------------------------------------------------
	''');
	}

	await _waitForAndHandleExit(
	serveLocalProcess: serveLocalProcess,
	flutterRunProcess: flutterRunProcess,
	);
	}

	Future<void> _waitForAndHandleExit({
	required Process serveLocalProcess,
	required Process? flutterRunProcess,
	}) async {
	final serveLocalProcessExited = Completer<int>();
	final flutterRunProcessExited = Completer<int>();
	unawaited(
	serveLocalProcess.exitCode.then((code) {
	serveLocalProcessExited.complete(code);
	}),
	);
	if (flutterRunProcess != null) {
	unawaited(
	flutterRunProcess.exitCode.then((code) {
	flutterRunProcessExited.complete(code);
	}),
	);
	}

	await Future.any([
	serveLocalProcessExited.future,
	flutterRunProcessExited.future,
	]);

	if (serveLocalProcessExited.isCompleted &&
	!flutterRunProcessExited.isCompleted &&
	flutterRunProcess != null) {
	final exitCode = await serveLocalProcessExited.future;
	logStatus(
	'Killing the flutterRunProcess because the serveLocalProcess has '
	'exited with code $exitCode.',
	);
	await _killProcess(flutterRunProcess);
	}

	if (flutterRunProcessExited.isCompleted &&
	!serveLocalProcessExited.isCompleted) {
	final exitCode = await flutterRunProcessExited.future;
	logStatus(
	'Killing the serveLocalProcess because the flutterRunProcess has '
	'exited with code $exitCode.',
	);
	await _killProcess(serveLocalProcess);
	}
	}

	Future<void> _killProcess(Process? process) async {
	if (process != null) {
	Process.killPid(process.pid, ProcessSignal.sigint);
	await process.exitCode;
	}
	}
	}