Important

This repo has moved to https://github.com/dart-lang/tools/tree/main/pkgs/bazel_worker

Tools for creating a persistent worker loop for bazel.

Usage

There are two abstract classes provided by this package, AsyncWorkerLoop and SyncWorkerLoop. These each have a performRequest method which you must implement.

Lets look at a simple example of a SyncWorkerLoop implementation:

import 'dart:io';
import 'package:bazel_worker/bazel_worker.dart';

void main() {
  // Blocks until it gets an EOF from stdin.
  SyncSimpleWorker().run();
}

class SyncSimpleWorker extends SyncWorkerLoop {
  /// Must synchronously return a [WorkResponse], since this is a
  /// [SyncWorkerLoop].
  WorkResponse performRequest(WorkRequest request) {
    File('hello.txt').writeAsStringSync('hello world!');
    return WorkResponse()..exitCode = EXIT_CODE_OK;
  }
}

And now the same thing, implemented as an AsyncWorkerLoop:

import 'dart:io';
import 'package:bazel_worker/bazel_worker.dart';

void main() {
  // Doesn't block, runs tasks async as they are received on stdin.
  AsyncSimpleWorker().run();
}

class AsyncSimpleWorker extends AsyncWorkerLoop {
  /// Must return a [Future<WorkResponse>], since this is an
  /// [AsyncWorkerLoop].
  Future<WorkResponse> performRequest(WorkRequest request) async {
    await File('hello.txt').writeAsString('hello world!');
    return WorkResponse()..exitCode = EXIT_CODE_OK;
  }
}

As you can see, these are nearly identical, it mostly comes down to the constraints on your package and personal preference which one you choose to implement.

Testing

A package:bazel_worker/testing.dart file is also provided, which can greatly assist with writing unit tests for your worker. See the test/worker_loop_test.dart test included in this package for an example of how the helpers can be used.

Features and bugs

Please file feature requests and bugs at the issue tracker.