forever
A simple CLI tool for ensuring that a given script runs continuously (i.e. forever).
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 <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
-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
-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"
}
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:
| Option | Description | Default |
|---|---|---|
| root | Directory to put all default forever log files | forever.root |
| pidPath | Directory to put all forever *.pid files | [root]/pids |
| sockPath | Directory for sockets for IPC between workers | [root]/sock |
| loglength | Number of logs to return in forever tail
|
100 |
| columns | Array of columns to display when format is true |
forever.config.get('columns') |
| debug | Boolean value indicating to run in debug mode | false |
| stream | Boolean value indicating if logs will be streamed | false |
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-nparameter totail. -
stream(boolean): is is used as the-fparameter totail.
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