A simple CLI tool for ensuring that a given script runs continuously (i.e. forever).
curl http://npmjs.org/install.sh | sh $ [sudo] npm install forever -gNote: If you are using forever programatically you should not install it globally.
$ cd /path/to/your/project
$ [sudo] npm install foreverThere are two distinct ways to use forever: through the command line interface, or by requiring the forever module in your own code.
You can use forever to run any kind of script continuously (whether it is written in node.js or not). The usage options are simple:
$ forever --help
usage: forever [options] [action] 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
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 <key> <val> Sets the specified forever config <key>
clear <key> Clears the specified forever config <key>
logs Lists log files for all forever processes
logs <script|index> Tails the logs for <script|index>
columns add <col> Adds the specified column to the output in `forever list`
columns rm <col> Removed the specified column from the output in `forever list`
columns set <cols> Set all columns 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
--pidFile The pid file
--sourceDir The source directory for which SCRIPT is relative to
--minUptime Minimum uptime (millis) for a script to not be considered "spinning"
--spinSleepTime Time to wait (millis) between launches of a spinning script.
--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
-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.jsYou can also use forever from inside your own node.js code.
var forever = require('forever');
var child = new (forever.Monitor)('your-filename.js', {
max: 3,
silent: true,
options: []
});
child.on('exit', this.callback);
child.start();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);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');
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')
'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': {
env: process.env, // Information passed along to the child process
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
}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
In addition to using a Forever object, the forever module also exposes some useful methods. Each method returns an instance of an EventEmitter which emits when complete. See the forever cli commands for sample usage.
Synchronously sets the specified configuration (config) for the forever module. There are two important options:
- root: Directory to put all default forever log files
- pidPath: Directory to put all forever *.pid files
Starts a script with forever.
Starts a script with forever as a daemon. WARNING: Will daemonize the current process.
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.
Stops all forever scripts currently running. This method returns an EventEmitter that raises the 'stopAll' event when complete.
Returns a list of metadata objects about each process that is being run using forever. This method is synchronous and will return the list of metadata as such. Only processes which have invoked forever.startServer() will be available from forever.list()
Responds with the logs from the target script(s) from tail. If length is provided it is used as the -n parameter to tail.
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.
Removes all log files from the root forever directory that do not belong to current running forever processes.
$ npm test