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Restart node upon changing a file
(9 answers)
Closed 7 years ago.
I found that forever can run nodejs server forever. Is forever supports this feautre?
-- If the nodejs script is modified changed, the server shld restarted automatically.
How can I enable this feature using forever? or I need something else?
From the forever readme. Use the -w flag to watch file for changes.
In case someone else, like myself, comes to find this through google.
I have to run it thusly:
forever --watch ./start/file
For me, at least, it defaults to watching the current directory I'm running the command in for changes. ./start/file is the file that "npm start" hits up from your package.json.
If you need to watch a different directory from where you're pwd shows you to be, try:
forever --watch --watchDirectory ./path/to/dir ./start/file
For some reason "forever start xxxxxxxxx" only brings up the help information for me, but this works. /me shrugs.
Again just another example of its usage (and it does work :D)
forever -w --watchDirectory . --watchIgnore *.log -o ./log/out.log -e ./log/err.log index.js
That will launch the app in the same process with output to stdout/stderr (but also written to the logs)
To launch it in prod watching is obviously not a good idea and running it as a deamon is probably what you are after so drop the -w flags and add the "start" command
forever -o ./log/out.log -e ./log/err.log start index.js
I personally use Nodemon to handle that. Its a replacement for the node server. It automatically restarts the server when your files are updated. You might want to check it out.
Related
I have a sailsjs app on AWS EC2, which I have been running till now using forever. I have two adantages using forever:
1) Perpetuality: I can use the CLI forever start app.js or forever restart app.js and then app starts running and keeps on running till I stop it with the command forever stop app.js. So, the app does not stop even when I close my terminal. The process keeps on running.
2) Runtime Log: I have a .forever directory that has a log file, while on real time records the server logs, and when I check the log using tail -f file_name.log, I get to see run time logs.
However there is a disadvantage: Every time I upload a new/modified server file, I have to restart the app manually. To get rid of this, I am switching from forever to nodemon.
From the documentation provided by Nodemon, I cant figure out how can I replicate the two advantages, as mentioned above, from Nodemon too. Will be a great help if anyone can guide me on how to start my nodejs app using nodemon so that it can keep running even after closing the terminal on my side, and how to watch runtime log of server.
Just my two cents.
I use nodemon daily while developing and I dont think its something you want to use in place of something like forever. Nodemon is used when developing, the software will detect when there has been a file change and restart the server but for deployment it should not be considered.
There is no need to change either because forever has this use case handled with the --w or --watchDirectory comand that will watch for file changes(It can be found here on their readme).
As you can tell by my question, I'm new to this...
I built my first website, I set up my first Node.js server to serve it and then pushed everything live on EC2.
I tested everything on my EC2 IP address and everything seems to be working.
Now up until now, I've been testing my app locally so it makes sense that whenever I closed the terminal, app.js would stop running so nothing would be served on localhost.
Now that my server is on EC2, the same thing happens ("obviously" one could say..) whenever I close my terminal.
So my question is how do I keep my Node.js server running on EC2 for like... forever..so that my site stays live.. forever :)
I read something about a node module called "forever" but I'm wondering (being new and all..) why isn't this "forever" functionality a default setting of the Node.js-EC2 system ?
I mean, correct me if I'm wrong, but isn't the whole point of setting up a web server and pushing it live to have it stay live forever? Isn't that what servers are supposed to do anyway (infinitely listening for requests) ? And if that's the case why do we need extra modules/settings to achieve that ?
Thanks for your help.. As you can tell I'm not only looking for a solution but an explanation as well because I got really confused.. :-)
EDIT (a few details you might need) - After installing my app on EC2 these are the steps that I follow on the terminal (The app is running on Amazon Linux by the way) :
I type ssh -i xxxxxxxxxxx.pem ec2-user#ec2-xx-xx-xx-x.eu-west-1.compute.amazonaws.com on the
terminal
After logging onto the Amazon machine I then go to the relevant folder and execute node app.js
There are 3 folders in the machine : node, node_modules and *name of my app*
app.js resides in *name of my app*
After that, the site goes live on my EC2 IP
Once I close the terminal, everything is switched off
Before you invoke Node.js, run the command:
screen
This will create a persistent environment which will allow your process to keep running after you disconnect.
When you reconnect, you can use this command to reconnect to that environment:
screen -r
Here's a random link to learn more about screen:
http://www.rackaid.com/blog/linux-screen-tutorial-and-how-to/
However, this won't help you if your EC2 instance restarts. There are many different ways to do that. Adding your startup command to /etc/rc.local is one way. Here's a link to an Amazon guide which includes adding something to /etc/rc.local.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/building-shared-amis.html
I worked with the valid answer for a while but some times the screen just end with no reason also screen has no balance loader and others features that in a production enviroment you should care , Currently I use a npm component to do this job.
https://www.npmjs.com/package/pm2
This is so easy to use.
$ npm install pm2 -g
then just start your app with pm2 like this
$ pm2 start app.js
In the above link you can find diferents tasks to perform if you need.
Hope this help the newbies like me.
There's a better way. Use forever.js.
See it here: https://github.com/foreverjs/forever
This is a nice tutorial for how to use chkconfig with forever on CENTOS.
http://aronduby.com/starting-node-forever-scripts-at-boot-w-centos/
Or use tmux
Just Enter a tmux screen run node server
Ctrl+b Hit D and you're done.
I am very late to join the thread and seems its basic problem with every newbie. Follow the below to setup properly your first server.
follow the step on the ec2 instance(before doing this make sure you have a start script for pm2 in your package.json file):
npm install pm2 -g
pm2 startup systemd
See the output and at the last line it must be like..
You have to run this command as root. Execute the following command:
sudo env PATH=$PATH:/usr/bin /usr/lib/node_modules/pm2/bin/pm2 startup
systemd -u sammy --hp /home/sammy
Take the last line command and run again with root privilege.
(before running the next command, Provide a new start script for pm2 in your package.json file e.g: "pm2-start": "pm2 start ./bin/www")
npm run pm2-start
for more info follow the link.
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-node-js-application-for-production-on-ubuntu-16-04
If you are using a Ubuntu EC2, better to use the following we have been using this for the past 6 years and have had no issues with this.
sudo npm i -g forever
Now start your main, example
forever start index.js
forever start src/server.js
To stop the server use the following command
forever stop index.js
To list multiple servers running forever
forever listall
What are the steps required for setting up a Node.js application on Webfaction shared hosting account?
Introduction
The result of the following instructions is a Node.js application that is running continously, produces logfiles and restarts itself even after the reboot of the server machine. The instructions are especially targeted for the shared host accounts on Webfaction but can be used for general purpose also.
Install Node.js
Eventhough Node.js download page offers Linux binaries, it would be more robust to install Node.js from source. Download the most recent source codes and extract them to ~/src/.
(log in to your webfaction console)
> mkdir -p ~/src/
> cd src/
> wget http://nodejs.org/dist/v0.10.18/node-v0.10.18.tar.gz
> tar -xzf node-v0.10.18.tar.gz
The next step is to compile and install the code. For this Python is used. Because the default python version is 2.4 (at least on my Webfaction server web223) and because the Node.js installation requires one of the versions 2.6+, you must temporarily set newer version to be the default. See the following snippet (also see this article for details). Note --prefix=$HOME which is required due Webfaction's environment restrictions (you have access only to your home directory).
> cd node-v0.10.18/
> alias python=python2.7
> python configure --prefix=$HOME
> make
> make install
Node.js installed. Verify the success by
> node -v
v0.10.18
That also installed node package manager npm.
> npm -v
1.3.8
Install Forever
To keep run Node.js application running as long as possible and logging the output for maintenance, you need Forever. For convenience, install it globally (for you) using flag -g.
> cd ~
> npm install -g forever
> forever --version
v0.10.8
You can later update forever by
> npm update -g forever
Start the Application
First, create a custom application via Webfaction Control Panel (Custom app (listening on port)). Name it for example foonode. You may also create a domain and website for the app.
Second, make a note about the socket port number that was given for the app by Webfaction. Let the example be 48888.
Third, copy your application code to the directory of the app i.e. ~/webapps/foonode/. After that the directory contents would for example be the following.
> cd ~/webapps/foonode/
> ls
node_modules/
index.js
Index.js would be something like the snippet below. The key point is using the given port number for the app.
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello Universe.\n');
}).listen(48888, '127.0.0.1');
console.log('Listening at http://127.0.0.1:48888/');
Now you could run the app by node index.js. However there is a problem: when you exit the shell, also the app exits. Therefore you should run the Node.js as a daemon. That is something where Forever does a lot for you. Start node with forever:
> cd ~/webapps/foonode/
> forever start index.js
Now the app continues running after you logout and, as a very nice thing to have, is quickly restarted if it happens to crash. This is a lot but still not enough. What if the server reboots? Where is the output from the app going? What if the script crashes continously? What if you have multiple scripts with the name index.js? Keep reading.
Use Absolute Paths with Forever
Forever identifies the process by the filename of the script fed to forever start <filename_of_script>. A problem arises when you have multiple applications with the same filename for the script.
For example consider you have two applications /home/foouser/webapps/foonode/index.js and /home/foouser/webapps/barnode/index.js. If you now start both with forever start index.js within the directories of the applications and then run forever stop index.js only once, the result is that both applications become stopped. This happens because they both had the same identity index.js
The solution is to use the absolute filepaths when specifying the script.
> forever start /home/foouser/webapps/foonode/index.js
And to stop execution:
> forever stop /home/foouser/webapps/foonode/index.js
This ensures that only the intended application becomes stopped. This habit of using absolute paths has also positive effects to forever list. See this issue for details.
Logging
To store the application output to somewhere, specify the following arguments.
-l <logfile> = stream all output to this file. Relative to ~/.forever/
-o <logfile> = stream script's stdout to this file. Relative to current dir.
-e <logfile> = stream script's stderr to this file. Relative to current dir.
-a = append to the files instead of overwriting them.
It seems convenient to have a subdirectory for the logs, e.g. logs/. With the arguments, absolute path and the subdirectory logs/ the command becomes the following:
> cd ~/webapps/foonode/
> mkdir -p logs/
> forever start -a -l forever.log -o logs/out.log -e logs/err.log /home/foouser/webapps/foonode/index.js
Detecting and Restarting a Spinning Process
Forever has the parameters --minUptime and --spinSleepTime which are not so well documented currently. The meaning of the parameters is to control situation where the script crashes and almost immediately crashes again after restart. As forever tries to restart the script as soon as possible after the crash, this can lead to a busy loop which may eat lots of resources of the server.
--minUptime specifies the number of milliseconds the script has to be up and running without crashes to be restarted immediately. If the uptime of the crashed script is less than minUptime, then the script is considered spinning i.e. problematic. If uptime is greater then the script is considered non-spinning.
If a spinning script crashes i.e. the uptime of the script is less than --minUptime then forever waits --spinSleepTime number of milliseconds before restarting the script. Otherwise the script is restarted as soon as possible. This prevents the resource-eating loop. See this answer for futher discussion.
I personally use 5000 for --minUptime to make sure that Node is fully started before declaring it non-spinning. 2000 would be a good one for --spinSleepTime to avoid the loop but still trying to start the script quickly after the problematic situation resolves.
> forever start -a -l forever.log -o logs/out.log -e logs/err.log --minUptime=5000 --spinSleepTime=2000 /home/foouser/webapps/foonode/index.js
Manage the Application
As the commands grow, memorizing and writing them becomes more and more cumbersome. Therefore it is convenient to copy them into a Makefile. The makefile also becomes handy later on when you need to specify a command to run after the server reboot.
> cd ~/webapps/foonode/
> cat Makefile
foreverstart:
# Run server forever (until reboot)
mkdir -p logs
forever start -a -l forever.log -o logs/out.log -e logs/err.log --minUptime 5000 --spinSleepTime 2000 /home/foouser/webapps/foonode/index.js
foreverstop:
forever stop /home/foouser/webapps/foonode/index.js
Keeping the Application Running
Forever does not cover the case where the server reboots. For that you need to specify a cronjob with #reboot rule that start the forever after reboot.
> export EDITOR=nano # Editor to use to edit crontab. A matter of taste.
> crontab -e
Add the following line and save.
#reboot make -C ~/webapps/foonode/ -f ~/webapps/foonode/Makefile foreverstart
The line ensures that foonode is started immediately after the server reboot. The flag -C specifies the directory to run the makefile from and -f the actual location of the makefile. See this answer for details about using #reboot.
Conclusion
Now you have a node process running truly forever or at least as long as there is maintenance guys feeding the server with electricity. Lots of things done but maybe more will come. Things you may like to do in the future which were not covered here includes the following.
Watching for file changes and automatically restarting when detected (See --watch in forever --help)
Using Grunt.js instead of Make (See bustardcelly/grunt-forever)
Backupping the application once in a while.
See also
Setting up Redis on Webfaction
Any ideas, comments or corrections?
Well, you probably already followed all the steps in the other answer (wow! such detail! great), but it is now a lot easier: they now have a one-click installer for node.js.
Another option is to install nvm (Node Version Manager) and type:
nvm install node
It's not only valid for Webfaction.
Since node is basically a single process, when something goes terribly wrong, the whole application dies.
I now have a couple of apps built on express and I am using some manual methods to prevent extended downtimes ( process.on('uncaughtException') and a custom heartbeat monitor ).
Any suggestions from the community?
Best-practices? Frameworks?
Thanks!
A
Use something like forever
or use supervisor.
Just npm link and then sudo supervisor server.js.
These types of libraries also support hot reloading. There are some which you use from the command line and they run node services as sub processes for you. There are others which expect you to write your code to reload itself.
Ideally what you want to move towards a full blown load balancer which is failure safe. If a single node proccess in your load balancer crashes you want it to be quietly restarted and all the connections and data rescued.
Personally I would recommend supervisor for development (It's written by isaacs!) and a full blown load balancer (either nginx or node) for your real production server.
Of course your already running multiple node server processes in parallel because you care about scaling across multiple cores right ;)
Use forever.
"A simple CLI tool for ensuring that a given script runs continuously (i.e. forever)"
Just install it with npm
npm install forever
and type
forever start app.js
Try to look at forever module.
If you're using Ubuntu you can use upstart (which is installed by default).
$ cat /etc/init/my_app.conf
description "my_app"
author "me"
start on (local-filesystems and net-device-up IFACE=eth0) stop on
shutdown
respawn
exec sh -c "env NODE_ENV=production node /path/myapp/app.js >> /var/log/node.log 2>&1"
"respawn" mean that the app will be restarted if it dies.
To start the app
start my_app
For other commands
man initctl
I'll strongly recommend forever too. I used it yesterday and its a breeze:
Install npm install forever
Start your app forever start myapp.js
Check if its working forever list
Try killing your app :
ps
Get your myapp.js pid and run kill <pid
run forever list and you'll see it's running again
You can try using Fugue, a library for node.js similar to Spark or Unicorn:
https://github.com/pgte/fugue
Fugue can manage any node.js server type, not just web servers, and it's set up and configured as a node.js script, not a CLI command, so normal node.js build & deployment toolchains can use it.
I connect to my remote server via ssh. Then I start my node.js app with Forever. Everything works fine until I close my console window. How to run node.js app FOREVER on my remote server even when I close my connection via ssh? I just want to start an app and shut down my copmputer. My app should be working in the background on my remote server.
You may also want to consider using the upstart utility. It will allow you to start, stop and restart you node application like a service. Upstart can configured to automatically restart your application if it crashes.
Install upstart:
sudo apt-get install upstart
Create a simple script for your application that will look something like:
#!upstart
description "my app"
start on started mountall
stop on shutdown
# Automatically Respawn:
respawn
respawn limit 99 5
env NODE_ENV=production
exec node /somepath/myapp/app.js >> /var/log/myapp.log 2>&1
Then copy the script file (myapp.conf) to /etc/init and make sure its marked as executable. Your application can then be managed using the following commands:
sudo start myapp
sudo stop myapp
sudo restart myapp
Two answers: One for Windows, one for *nix:
On Windows, you can use the start command to start the process disconnected from your instance of cmd.exe:
start node example.js
On *nix, there are two aspects of this: Disconnecting the process from the console, and making sure it doesn't receive the HUP signal ("hang up"), which most processes (including Node) will respond to by terminating. The former is possibly optional, but the latter is necessary.
Starting disconnected from the console is easy: Usually, you just put an ampersand (&) at the end of the command line:
# Keep reading, don't just grab this and use it
node example.js &
But the above doesn't protect the process from HUP signals. The program may or may not receive HUP when you close the shell (console), depending on a shell option called huponexit. If huponexit is true, the process will receive HUP when the shell exits and will presumably terminate.
huponexit defaults to false on the various Linux variants I've used, and in fact I happily used the above for years until coderjoe and others helped me understand (in a very long comment stream under the answer that may have since been deleted) that I was relying on huponexit being false.
To avoid the possibility that huponexit might be true in your environment, explicitly use nohup. nohup runs the process immune from HUP signals. You use it like this:
nohup node example.js > /dev/null &
or
nohup node example.js > your-desired-filename-or-stream-here &
The redirection is important; if you don't do it, you'll end up with a nohup.out file containing the output from stdout and stderr. (By default, nohup redirects stderr to stdout, and if stdout is outputting to a terminal, it redirects that to nohup.out. nohup also redirects stdin if it's receiving from a terminal, so we don't have to do that. See man nohup or info coreutils 'nohup invocation' for details.)
In general for these things, you want to use a process monitor so that if the process crashes for some reason, the monitor restarts it, but the above does work for simple cases.
I would definitely recommend pm2
npm install -g pm2
To start server: pm2 start [yourServerFile.js]
To stop server: pm2 stop [yourServerFile.js]
Close client and server will run forever....will also restart if app crashes.
Ive been running a node server on Ubuntu for months with zero issues
Always, simple is the best, no need upstart, no need forever, just nohup:
nohup node file.js &
Believe me, I'm running so that for my case!
You could install forever using npm like this:
sudo npm install -g forever
Or as a service:
forever start server.js
Or stop service
forever stop server.js
To list all running processes:
forever list
node expamle.js & for example
In Linux, SSH into your remote server and run
screen
to launch into a new screen.
Finally, type ctrlad to detach the screen session without killing the process.
More info here.
I had similar issue and I think using forever will help to handle crashed and restarts
You can install forever globally:
sudo nom install -g forever
And run this command:
nohup forever server.js &
This should handle all the trouble of closing the terminal, closing ssh session, node crashes and restarts.
If you're running node.js in a production environment, you should consider using PM2, forever.js, or Nodemon.
There is no shortage of articles online comparing the different packages.
This is only a partial answer for Windows. I’ve created a single line Visual Basic Script called app.vbs that will start your node application within a hidden window:
CreateObject("Wscript.Shell").Run "node app.js", 0
To execute it automatically at startup, open the %AppData%\Microsoft\Windows\Start Menu\Programs\Startup\ directory and add a shortcut to the app.vbs file.
More info at: https://keestalkstech.com/2016/07/start-nodejs-app-windowless-windows/
Wow, I just found a very simple solution:
First, start your process (node app)
forever dist/index.js
run: ^Z cmd + z.
Then: bg. Yeah.. bg (background).
And pum.. you are out.
Finish with exitif you are with sshor just close the terminal.
my start.sh file:
#/bin/bash
nohup forever -c php artisan your:command >>storage/logs/yourcommand.log 2>&1 &
There is one important thing only. FIRST COMMAND MUST BE "nohup", second command must be "forever" and "-c" parameter is forever's param, "2>&1 &" area is for "nohup". After running this line then you can logout from your terminal, relogin and run "forever restartall" voilaa... You can restart and you can be sure that if script halts then forever will restart it.
I <3 forever