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forever-monitor Build Status

The core monitoring functionality of forever without the CLI


You can also use forever from inside your own node.js code.

  var forever = require('forever-monitor');

  var child = new (forever.Monitor)('your-filename.js', {
    max: 3,
    silent: true,
    options: []

  child.on('exit', function () {
    console.log('your-filename.js has exited after 3 restarts');

Spawning a non-node process

You can spawn non-node processes too. Either set the command key in the options hash or pass in an Array in place of the file argument like this:

  var forever = require('forever-monitor');
  var child = forever.start([ 'perl', '-le', 'print "moo"' ], {
    max : 1,
    silent : true

Options available when using Forever in node.js

There are several options that you should be aware of when using forever. Most of this configuration is optional.

    // Basic configuration options
    'silent': false,            // Silences the output from stdout and stderr in the parent process
    'uid': 'your-UID'           // Custom uid for this forever process. (default: autogen)
    'pidFile': 'path/to/', // Path to put pid information for the process(es) started
    'max': 10,                  // Sets the maximum number of times a given script should run
    'killTree': true            // Kills the entire child process tree on `exit`
    // These options control how quickly forever restarts a child process
    // as well as when to kill a "spinning" process
    'minUptime': 2000,     // Minimum time a child process has to be up. Forever will 'exit' otherwise.
    'spinSleepTime': 1000, // Interval between restarts if a child is spinning (i.e. alive < minUptime).
    // Command to spawn as well as options and other vars 
    // (env, cwd, etc) to pass along
    'command': 'perl',         // Binary to run (default: 'node')
    'options': ['foo','bar'],  // Additional arguments to pass to the script,
    'sourceDir': 'script/path' // Directory that the source script is in
    // Options for restarting on watched files.
    'watch': false              // Value indicating if we should watch files.
    'watchIgnoreDotFiles': null // Dot files we should read to ignore ('.foreverignore', etc).
    'watchIgnorePatterns': null // Ignore patterns to use when watching files.
    'watchDirectory': null      // Top-level directory to watch from.
    // All or nothing options passed along to `child_process.spawn`.
    'spawnWith': {
      customFds: [-1, -1, -1], // that forever spawns.
      setsid: false
    // More specific options to pass along to `child_process.spawn` which 
    // will override anything passed to the `spawnWith` option
    'env': { 'ADDITIONAL': 'CHILD ENV VARS' }
    'cwd': '/path/to/child/working/directory'
    // Log files and associated logging options for this instance
    'logFile': 'path/to/file', // Path to log output from forever process (when daemonized)
    'outFile': 'path/to/file', // Path to log output from child stdout
    'errFile': 'path/to/file'  // Path to log output from child stderr

Events available when using an instance of Forever in node.js

Each forever object is an instance of the node.js core EventEmitter. There are several core events that you can listen for:

  • error [err]: Raised when an error occurs
  • start [process, data]: Raised when the target script is first started.
  • stop [process]: Raised when the target script is stopped by the user
  • restart [forever]: Raised each time the target script is restarted
  • exit [forever]: Raised when the target script actually exits (permenantly).
  • stdout [data]: Raised when data is received from the child process' stdout
  • stderr [data]: Raised when data is received from the child process' stderr


  $ npm install forever-monitor

Run Tests

  $ npm test

License: MIT

Author: Charlie Robbins

Contributors: Fedor Indutny, James Halliday, Charlie McConnell, Maciej Malecki