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,
args: []
});
child.on('exit', function () {
console.log('your-filename.js has exited after 3 restarts');
});
child.start();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
});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/a.pid', // 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')
'args': ['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': true, // Value indicating if we should watch files.
'watchIgnoreDotFiles': null, // Whether to ignore file starting with a '.'
'watchIgnorePatterns': null, // Ignore patterns to use when watching files.
'watchDirectory': null, // Top-level directory to watch from. You can provide multiple watchDirectory options to watch multiple directories (e.g. for cli: forever start -w='app' -w='some_other_directory' app\index.js)
//
// All or nothing options passed along to `child_process.spawn`.
//
'spawnWith': {
customFds: [-1, -1, -1], // that forever spawns.
setsid: false,
uid: 0, // Custom UID
gid: 0, // Custom GID
shell: false // Windows only - makes forever spawn in a shell
},
//
// 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
//
// ### function parseCommand (command, args)
// #### @command {String} Command string to parse
// #### @args {Array} Additional default arguments
//
// Returns the `command` and the `args` parsed from
// any command. Use this to modify the default parsing
// done by 'forever-monitor' around spaces.
//
'parser': function (command, args) {
return {
command: command,
args: args
};
}
}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 (permanently).
- stdout [data]: Raised when data is received from the child process' stdout
- stderr [data]: Raised when data is received from the child process' stderr
When running the forever CLI tool, it produces debug outputs about which files have changed / how processes exited / etc. To get a similar behaviour with forever-monitor, add the following event listeners:
const child = new (forever.Monitor)('your-filename.js');
child.on('watch:restart', function(info) {
console.error('Restarting script because ' + info.file + ' changed');
});
child.on('restart', function() {
console.error('Forever restarting script for ' + child.times + ' time');
});
child.on('exit:code', function(code) {
console.error('Forever detected script exited with code ' + code);
}); $ npm install forever-monitor $ npm test