runfork

runfork runs a Node.js script isolated as a process.

Installation

$ npm install runfork

Quick start

To use runfork first you need to add a reference to your application.

const runfork = require('runfork');

Then to run a Node.js script, run runfork and provide the path to the script using an options object. In case the script can not be started, an exception is thrown.

const stop = runfork({ path: './app.js' });

Passing arguments to the fork

You can also pass arguments to the fork.

const stop = runfork({
  path: './app.js',
  args: ['--type', 'test'],
});

Passing environment variables to the fork

From time to time you need to set environment variables for the script being called. To do so provide an env property in the options object that contains the environment variables as key-value pairs.

const stop = runfork({
  path: './app.js',
  env: {
    PORT: 3000
  }
});

Sending messages from the fork to the parent

To send messages from the fork to the parent use the process.send function from within your fork. In the parent provide an onMessage function to receive the messages:

const stop = runfork({
  path: './app.js',
  onMessage (message) {
    // ...
  }
});

Stopping the fork

Sometimes, e.g. when executing a long-running task, it may be necessary to stop the fork. For this, call the stop function that is returned.

This function will send 10 SIGINT signals with 10ms breaks in between. If the process does not respond to this, it finally sends a SIGKILL signal to kill the process.

As the stop function returns a promise, you can wait for the process to terminate.

const stop = runfork({ path: './app.js' });

// ...

await stop();

Detecting when the fork exits

To get notified when the script exits, provide the onExit property in the options object. This function will get called with the exit code as well as the stdout and the stderr streams.

const stop = runfork({
  path: './app.js',
  onExit (exitCode, stdout, stderr) {
    // ...
  }
});

Running the build

To build this module use roboter.

$ bot

License

The MIT License (MIT) Copyright (c) 2016-2018 the native web.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.