Restart Aqueduct devserver upon file change [ Attemp #1 ]. Replace `bin/main.dart` with this.

main.dart

/// Tried to autoreloading aqueduct on code change. First attempt off my head.
/// Dependency: `watcher: ^0.9.7+10`, maybe this whole thing is a bad idea?
///
/// TODO:
/// 1. Refactor so that it has minimal code change from the generated `bin/main.dart`
/// 2. Reload only once if lots of files change (i.e. scaffolding while devserver was running)
/// 3. Take hints from configuration file
/// 4. What to do if error occurs?
import "package:watcher/watcher.dart";

import 'package:backend/backend.dart';

Future _getApp([List<String> infoMessages]) async {
  final app = Application<BackendChannel>()
    ..options.configurationFilePath = "config.yaml"
    ..options.port = 8888;

  final count = Platform.numberOfProcessors ~/ 2;
  await app.start(numberOfInstances: count > 0 ? count : 1);

  print(infoMessages.join("\n"));

  return app;
}

Future runApp() async {
  var app = await _getApp(["App started on port: 8888", "CTRL+C to Exit"]);

  final watcher =
      DirectoryWatcher("lib"); // From config, and do some path-fu here?
  watcher.events.listen((event) async {
    final bool shouldReload = // From config? Maybe throttling here?
        [ChangeType.REMOVE, ChangeType.MODIFY].contains(event.type) ||
            event.path.endsWith(".dart");
    if (shouldReload) {
      await app.stop();
      app = await _getApp(["File Changed: ${event}, reload app"]);
    }
  });
}

Future main() async {
  await runApp();
}