observable-process

Node.js Child Process Observer

A high-level API for spawning child processes in Node.js and waiting until they output a certain text.

ObservableProcess = require('observable-process');

observer = new ObservableProcess('my-server --port 3000');
observer.wait('listening on port 3000', function() {
  // the child process says it is ready now
});

More details around waiting for output of spawned processes in the spec and its implementation.

Logging the output

• by default the output of the observed process is hidden
• provide the option verbose: true to log the output on stdio
• provide custom console streams via the option console

observer = new ObservableProcess('my-server', { verbose: true });
// output goes to your terminal

observer = new ObservableProcess('my-server', { verbose: true, console: myConsole });
// output goes to your myConsole object

More details around logging options in the spec and its implementation.

Killing the process

If the process is running, you can kill it via:

observer.kill()

To let ObservableProcess notify you when a process ended, provide it a callback via the onExit parameter:

observer = new ObservableProcess('my-server', onExit: function() {
  // here the server has ended/crashed
});

related libraries

• nexpect: Allows to define expectations on command output, and send it input, but doesn't allow to add more listeners to existing long-running processes, which makes declarative testing hard.