process to - How do I run a node.js app as a background service?




ubuntu closed (21)

I am simply using the daemon npm module:

var daemon = require('daemon');

daemon.daemonize({
    stdout: './log.log'
  , stderr: './log.error.log'
  }
, './node.pid'
, function (err, pid) {
  if (err) {
    console.log('Error starting daemon: \n', err);
    return process.exit(-1);
  }
  console.log('Daemonized successfully with pid: ' + pid);

  // Your Application Code goes here
});

Lately I'm also using mon(1) from TJ Holowaychuk to start and manage simple node apps.

Since this post has gotten a lot of attention over the years, I've listed the top solutions per platform at the bottom of this post.


Original post:

I want my node.js server to run in the background, i.e.: when I close my terminal I want my server to keep running. I've googled this and came up with this tutorial, however it doesn't work as intended. So instead of using that daemon script, I thought I just used the output redirection (the 2>&1 >> file part), but this too does not exit - I get a blank line in my terminal, like it's waiting for output/errors.

I've also tried to put the process in the background, but as soon as I close my terminal the process is killed as well.

So how can I leave it running when I shut down my local computer?


Top solutions:

  • Systemd (Linux)
  • Launchd (Mac)
  • node-windows (Windows)
  • PM2 (Node.js)

Its very simple.

  1. Add package.json in your project
  2. Add script file name or path in your Package.JSON Start
  3. Then simple go to your console open your project directory by cd path/to/directory/
  4. Write nohup npm start

Following is a Package.JSON sample that anyone can use. { "name": "Project",

  "version": "1.0.0",

  "main": "httpsserver.js",

  "scripts": {

    "start": "node httpsserver.js"
  },

  "keywords": [],

  "author": "",

  "license": "ISC",

  "dependencies": {},

  "devDependencies": {},

  "description": ""

}

If you are running OSX, then the easiest way to produce a true system process is to use launchd to launch it.

Build a plist like this, and put it into the /Library/LaunchDaemons with the name top-level-domain.your-domain.application.plist (you need to be root when placing it):

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>top-level-domain.your-domain.application</string>

    <key>WorkingDirectory</key>
    <string>/your/preferred/workingdirectory</string>

    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/node</string>
        <string>your-script-file</string>
    </array>

    <key>RunAtLoad</key>
    <true/>

    <key>KeepAlive</key>
    <true/>

</dict>
</plist>

When done, issue this (as root):

launchctl load /Library/LaunchDaemons/top-level-domain.your-domain.application.plist
launchctl start top-level-domain.your-domain.application

and you are running.

And you will still be running after a restart.

For other options in the plist look at the man page here: https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man5/launchd.plist.5.html


Try to run this command if you are using nohup -

nohup npm start 2>/dev/null 1>/dev/null&

You can also use forever to start server

forever start -c "npm start" ./ 

If you simply want to run the script uninterrupted until it completes you can use nohop as already mentioned in the answers here. However, none of the answers provide a full command that also logs stdin and stdout.

nohup node index.js >> app.log 2>&1 &
  • The >> means append to app.log.
  • 2>&1 makes sure that errors are also send to stdout and added to the app.log.
  • The ending & makes sure your current terminal is disconnected from command so you can continue working.

If you want to run a node server (or something that should start back up when the server restarts) you should use systemd / systemctl.


I use tmux for a multiple window/pane development environment on remote hosts. It's really simple to detach and keep the process running in the background. Have a look at tmux


has anyone noticed a trivial mistaken of the position of "2>&1" ?

2>&1 >> file

should be

>> file 2>&1

2016 Update: The node-windows/mac/linux series uses a common API across all operating systems, so it is absolutely a relevant solution. However; node-linux generates systemv init files. As systemd continues to grow in popularity, it is realistically a better option on Linux. PR's welcome if anyone wants to add systemd support to node-linux :-)

Original Thread:

This is a pretty old thread now, but node-windows provides another way to create background services on Windows. It is loosely based on the nssm concept of using an exe wrapper around your node script. However; it uses winsw.exe instead and provides a configurable node wrapper for more granular control over how the process starts/stops on failures. These processes are available like any other service:

The module also bakes in some event logging:

Daemonizing your script is accomplished through code. For example:

var Service = require('node-windows').Service;

// Create a new service object
var svc = new Service({
  name:'Hello World',
  description: 'The nodejs.org example web server.',
  script: 'C:\\path\\to\\my\\node\\script.js'
});

// Listen for the "install" event, which indicates the
// process is available as a service.
svc.on('install',function(){
  svc.start();
});

// Listen for the "start" event and let us know when the
// process has actually started working.
svc.on('start',function(){
  console.log(svc.name+' started!\nVisit http://127.0.0.1:3000 to see it in action.');
});

// Install the script as a service.
svc.install();

The module supports things like capping restarts (so bad scripts don't hose your server) and growing time intervals between restarts.

Since node-windows services run like any other, it is possible to manage/monitor the service with whatever software you already use.

Finally, there are no make dependencies. In other words, a straightforward npm install -g node-windows will work. You don't need Visual Studio, .NET, or node-gyp magic to install this. Also, it's MIT and BSD licensed.

In full disclosure, I'm the author of this module. It was designed to relieve the exact pain the OP experienced, but with tighter integration into the functionality the Operating System already provides. I hope future viewers with this same question find it useful.


To round out the various options suggested, here is one more: the daemon command in GNU/Linux, which you can read about here: http://libslack.org/daemon/manpages/daemon.1.html. (apologies if this is already mentioned in one of the comments above).


June 2017 Update:
Solution for Linux: (Red hat). Previous comments doesn't work for me. This works for me on Amazon Web Service - Red Hat 7. Hope this works for somebody out there.

A. Create the service file 
sudo vi /etc/systemd/system/myapp.service
[Unit]
Description=Your app
After=network.target

[Service]
ExecStart=/home/ec2-user/meantodos/start.sh
WorkingDirectory=/home/ec2-user/meantodos/

[Install]
WantedBy=multi-user.target

B. Create a shell file
/home/ec2-root/meantodos/start.sh
#!/bin/sh -
sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to 8080
npm start

then:
chmod +rx /home/ec2-root/meantodos/start.sh
(to make this file executable)

C. Execute the Following

sudo systemctl daemon-reload
sudo systemctl start myapp
sudo systemctl status myapp

(If there are no errors, execute below.  Autorun after server restarted.)
chkconfig myapp -add

use nssm the best solution for windows, just download nssm, open cmd to nssm directory and type

nssm install <service name> <node path> <app.js path> 

eg: nssm install myservice "C:\Program Files\nodejs" "C:\myapp\app.js" 

this will install a new windows service which will be listed at services.msc from there you can start or stop the service, this service will auto start and you can configure to restart if it fails.


I use Supervisor for development. It just works. When ever you make changes to a .js file Supervisor automatically restarts your app with those changes loaded.

Here's a link to its Github page

Install :

sudo npm install supervisor -g

You can easily make it watch other extensions with -e. Another command I use often is -i to ignore certain folders.

You can use nohup and supervisor to make your node app run in the background even after you log out.

sudo nohup supervisor myapp.js &


This answer is quite late to the party, but I found that the best solution was to write a shell script that used the both the screen -dmS and nohup commands.

screen -dmS newScreenName nohup node myserver.js >> logfile.log

I also add the >> logfile bit on the end so I can easily save the node console.log() statements.

Why did I use a shell script? Well I also added in an if statement that checked to see if the node myserver.js process was already running.

That way I was able to create a single command line option that both lets me keep the server going and also restart it when I have made changes, which is very helpful for development.



UPDATE - As mentioned in one of the answers below, PM2 has some really nice functionality missing from forever. Consider using it.

Original Answer

Use nohup:

nohup node server.js &

EDIT I wanted to add that the accepted answer is really the way to go. I'm using forever on instances that need to stay up. I like to do npm install -g forever so it's in the node path and then just do forever start server.js


Copying my own answer from How do I run a Node.js application as its own process?

2015 answer: nearly every Linux distro comes with systemd, which means forever, monit, etc are no longer necessary - your OS already handles these tasks.

Make a myapp.service file (replacing 'myapp' with your app's name, obviously):

[Unit]
Description=My app

[Service]
ExecStart=/var/www/myapp/app.js
Restart=always
User=nobody
# Note Debian/Ubuntu uses 'nogroup', RHEL/Fedora uses 'nobody'
Group=nogroup
Environment=PATH=/usr/bin:/usr/local/bin
Environment=NODE_ENV=production
WorkingDirectory=/var/www/myapp

[Install]
WantedBy=multi-user.target

Note if you're new to Unix: /var/www/myapp/app.js should have #!/usr/bin/env node on the very first line.

Copy your service file into the /etc/systemd/system.

Start it with systemctl start myapp.

Enable it to run on boot with systemctl enable myapp.

See logs with journalctl -u myapp

This is taken from How we deploy node apps on Linux, 2018 edition, which also includes commands to generate an AWS/DigitalOcean/Azure CloudConfig to build Linux/node servers (including the .service file).


The accepted answer is probably the best production answer, but for a quick hack doing dev work, I found this:

nodejs scriptname.js & didn't work, because nodejs seemed to gobble up the &, and so the thing didn't let me keep using the terminal without scriptname.js dying.

But I put nodejs scriptname.js in a .sh file, and nohup sh startscriptname.sh & worked.

Definitely not a production thing, but it solves the "I need to keep using my terminal and don't want to start 5 different terminals" problem.


I am surprised that nobody has mentioned Guvnor

I have tried forever, pm2, etc. But, when it comes to solid control and web based performance metrics, I have found Guvnor to be by far the best. Plus, it is also fully opensource.

Edit : However, I am not sure if it works on windows. I've only used it on linux.


PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks. https://github.com/Unitech/pm2


UPDATE: i updated to include the latest from pm2:

for many use cases, using a systemd service is the simplest and most appropriate way to manage a node process. for those that are running numerous node processes or independently-running node microservices in a single environment, pm2 is a more full featured tool.

https://github.com/unitech/pm2

http://pm2.io

  • it has a really useful monitoring feature -> pretty 'gui' for command line monitoring of multiple processes with pm2 monit or process list with pm2 list
  • organized Log management -> pm2 logs
  • other stuff:
    • Behavior configuration
    • Source map support
    • PaaS Compatible
    • Watch & Reload
    • Module System
    • Max memory reload
    • Cluster Mode
    • Hot reload
    • Development workflow
    • Startup Scripts
    • Auto completion
    • Deployment workflow
    • Keymetrics monitoring
    • API

You may write to a file using fs (file system) module.

Here is an example of how you may do it:

const fs = require('fs');

const writeToFile = (fileName, callback) => {
  fs.open(fileName, 'wx', (error, fileDescriptor) => {
    if (!error && fileDescriptor) {
      // Do something with the file here ...
      fs.writeFile(fileDescriptor, newData, (error) => {
        if (!error) {
          fs.close(fileDescriptor, (error) => {
            if (!error) {
              callback(false);
            } else {
              callback('Error closing the file');
            }
          });
        } else {
          callback('Error writing to new file');
        }
      });
    } else {
      callback('Could not create new file, it may already exists');
    }
  });
};

You might also want to get rid of this callback-inside-callback code structure by useing Promises and async/await statements. This will make asynchronous code structure much more flat. For doing that there is a handy util.promisify(original) function might be utilized. It allows us to switch from callbacks to promises. Take a look at the example with fs functions below:

// Dependencies.
const util = require('util');
const fs = require('fs');

// Promisify "error-back" functions.
const fsOpen = util.promisify(fs.open);
const fsWrite = util.promisify(fs.writeFile);
const fsClose = util.promisify(fs.close);

// Now we may create 'async' function with 'await's.
async function doSomethingWithFile(fileName) {
  const fileDescriptor = await fsOpen(fileName, 'wx');
  
  // Do something with the file here...
  
  await fsWrite(fileDescriptor, newData);
  await fsClose(fileDescriptor);
}




node.js process background server daemon