To help you get started, we've collected the most common ways that forever is being used within popular public projects.

appnexus / sicksync / bin / remote.js View on Github

/**
 *  Bootstrapper for remote-daemon.js
 *
 *  Triggered by first run of sicksync client, through ssh connection
 *  This file should only run on your devbox, (IE, in the data center).
 *  
 */

 console.log('starting daemon');

var forever = require('forever'),
    daemonFilePath = './sicksync-dev/lib/remote-daemon.js';

// TODO: change these files paths, right now they output to user's home location on remote server
// due to the fact that the process.cwd() is /home/cdopuch
var daemon = forever.startDaemon(
    daemonFilePath,
    {
        // NOTE: these log files are truncated on each new run
        // TODO: rotate the logs so we can save old logs
        'logFile': 'new-remote-daemon.log',
        'outFile': 'new-remote-daemon-stdout.log',
        'errFile': 'new-remote-daemon-stderr.log',
        'max': 1,
        'uid': 'remote-daemon'
    }
);
var server = forever.startServer(daemon);

// process.stdout.write('[remote.js] up and waiting');
console.log('[remote.js] up and waiting');

View more ways to use forever

forever

A simple CLI tool for ensuring that a given script runs continuously (i.e. forever). Note that this project currently fully depends on the community for implementing fixes and new features. For new installations we encourage you to use pm2 or nodemon

Installation

  $ [sudo] npm install forever -g

Note: If you are using forever programmatically you should install forever-monitor.

  $ cd /path/to/your/project
  $ [sudo] npm install forever-monitor

Usage

There are two ways to use forever: through the command line or by using forever in your code. Note: If you are using forever programatically you should install forever-monitor.

Command Line Usage

You can use forever to run scripts continuously (whether it is written in node.js or not).

Example

forever start app.js

Options

  $ forever --help
  usage: forever [action] [options] SCRIPT [script-options]

  Monitors the script specified in the current process or as a daemon

  actions:
    start               Start SCRIPT as a daemon
    stop                Stop the daemon SCRIPT by Id|Uid|Pid|Index|Script
    stopall             Stop all running forever scripts
    restart             Restart the daemon SCRIPT
    restartall          Restart all running forever scripts
    list                List all running forever scripts
    config              Lists all forever user configuration
    set       Sets the specified forever config 
    clear          Clears the specified forever config 
    logs                Lists log files for all forever processes
    logs  Tails the logs for 
    columns add    Adds the specified column to the output in `forever list`. Supported columns: 'uid', 'command', 'script', 'forever', 'pid', 'id', 'logfile', 'uptime'
    columns rm     Removed the specified column from the output in `forever list`
    columns set   Set all columns for the output in `forever list`
    columns reset       Resets all columns to defaults for the output in `forever list`
    cleanlogs           [CAREFUL] Deletes all historical forever log files

  options:
    -m  MAX          Only run the specified script MAX times
    -l  LOGFILE      Logs the forever output to LOGFILE
    -o  OUTFILE      Logs stdout from child script to OUTFILE
    -e  ERRFILE      Logs stderr from child script to ERRFILE
    -p  PATH         Base path for all forever related files (pid files, etc.)
    -c  COMMAND      COMMAND to execute (defaults to node)
    -a, --append     Append logs
    -f, --fifo       Stream logs to stdout
    -n, --number     Number of log lines to print
    --pidFile        The pid file
    --uid            DEPRECATED. Process uid, useful as a namespace for processes (must wrap in a string)
                     e.g. forever start --uid "production" app.js
                         forever stop production
    --id             DEPRECATED. Process id, similar to uid, useful as a namespace for processes (must wrap in a string)
                     e.g. forever start --id "test" app.js
                         forever stop test
    --sourceDir      The source directory for which SCRIPT is relative to
    --workingDir     The working directory in which SCRIPT will execute
    --minUptime      Minimum uptime (millis) for a script to not be considered "spinning"
    --spinSleepTime  Time to wait (millis) between launches of a spinning script.
    --colors         --no-colors will disable output coloring
    --plain          Disable command line colors
    -d, --debug      Forces forever to log debug output
    -v, --verbose    Turns on the verbose messages from Forever
    -s, --silent     Run the child script silencing stdout and stderr
    -w, --watch      Watch for file changes
    --watchDirectory Top-level directory to watch from
    --watchIgnore    To ignore pattern when watch is enabled (multiple option is allowed)
    -t, --killTree   Kills the entire child process tree on `stop`
    --killSignal     Support exit signal customization (default is SIGKILL),
                     used for restarting script gracefully e.g. --killSignal=SIGTERM
                     Any console output generated after calling `forever stop/stopall` will not appear in the logs
    -h, --help       You're staring at it

  [Long Running Process]
    The forever process will continue to run outputting log messages to the console.
    ex. forever -o out.log -e err.log my-script.js

  [Daemon]
    The forever process will run as a daemon which will make the target process start
    in the background. This is extremely useful for remote starting simple node.js scripts
    without using nohup. It is recommended to run start with -o -l, & -e.
    ex. forever start -l forever.log -o out.log -e err.log my-daemon.js
        forever stop my-daemon.js

There are several examples designed to test the fault tolerance of forever. Here's a simple usage example:

  $ forever -m 5 examples/error-on-timer.js

JSON Configuration Files

In addition to passing forever the path to a script (along with accompanying options, described above), you may also pass forever the path to a JSON file containing these options. For example, consider an application with the following file structure:

.
├── forever
│   └── development.json
└── index.js

// forever/development.json
{
	// Comments are supported
    "uid": "app",
    "append": true,
    "watch": true,
    "script": "index.js",
    "sourceDir": "/home/myuser/app",
    "logFile": "/home/myuser/logs/forever.log",
    "outFile": "/home/myuser/logs/out.log",
    "errFile": "/home/myuser/logs/error.log"
}

This application could be started with forever, as shown below:

$ forever start ./forever/development.json

Absolute paths to such configuration files are also supported:

$ forever start /home/myuser/app/forever/development.json

Note: Forever parses JSON configuration files using shush, allowing the use of in-line comments within such files.

Multi-App Configuration Files

JSON configuration files can also be used to define the startup options for multiple applications, as shown below.

[
  {
    // App1
    "uid": "app1",
    "append": true,
    "watch": true,
    "script": "index.js",
    "sourceDir": "/home/myuser/app1"
  },
  {
    // App2
    "uid": "app2",
    "append": true,
    "watch": true,
    "script": "index.js",
    "sourceDir": "/home/myuser/app2",
    "args": ["--port", "8081"]
  }
]

Using In Your Code

The forever module exposes some useful methods to use in your code. Each method returns an instance of an EventEmitter which emits when complete. See the forever cli commands for sample usage.

Remark: As of forever@0.6.0 processes will not automatically be available in forever.list(). In order to get your processes into forever.list() or forever list you must instantiate the forever socket server:

  forever.startServer(child);

This method takes multiple forever.Monitor instances which are defined in the forever-monitor dependency.

forever.load (config)

Synchronously sets the specified configuration (config) for the forever module. There are two important options:

forever.start (file, options)

Starts a script with forever. The options object is what is expected by the Monitor of forever-monitor.

forever.startDaemon (file, options)

Starts a script with forever as a daemon. WARNING: Will daemonize the current process. The options object is what is expected by the Monitor of forever-monitor.

forever.stop (index)

Stops the forever daemon script at the specified index. These indices are the same as those returned by forever.list(). This method returns an EventEmitter that raises the 'stop' event when complete.

forever.stopAll (format)

Stops all forever scripts currently running. This method returns an EventEmitter that raises the 'stopAll' event when complete.

The format parameter is a boolean value indicating whether the returned values should be formatted according to the configured columns which can set with forever columns or programmatically forever.config.set('columns').

forever.list (format, callback)

Returns a list of metadata objects about each process that is being run using forever. This method will return the list of metadata as such. Only processes which have invoked forever.startServer() will be available from forever.list()

The format parameter is a boolean value indicating whether the returned values should be formatted according to the configured columns which can set with forever columns or programmatically forever.config.set('columns').

forever.tail (target, options, callback)

Responds with the logs from the target script(s) from tail. There are two options:

• length (numeric): is is used as the -n parameter to tail.
• stream (boolean): is is used as the -f parameter to tail.

forever.cleanUp ()

Cleans up any extraneous forever *.pid files that are on the target system. This method returns an EventEmitter that raises the 'cleanUp' event when complete.

forever.cleanLogsSync (processes)

Removes all log files from the root forever directory that do not belong to current running forever processes. Processes are the value returned from Monitor.data in forever-monitor.

forever.startServer (monitor0, monitor1, ..., monitorN)

Starts the forever HTTP server for communication with the forever CLI. NOTE: This will change your process.title. This method takes multiple forever.Monitor instances which are defined in the forever-monitor dependency.

Logging and output file locations

By default forever places all of the files it needs into /$HOME/.forever. If you would like to change that location just set the FOREVER_ROOT environment variable when you are running forever:

FOREVER_ROOT=/etc/forever forever start index.js

Make sure that the user running the process has the appropriate privileges to read & write to this directory.

Run Tests

  $ npm test

License: MIT

Author: Charlie Robbins

Maintainer: Igor Savin

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