I am running a node.js application in Windows and I want to make it automatically restart if there is an unhandled exception in the code which causes the application to stop.
I have done some research and I found that a combination "Forever" and "Nodemon" can achieve this goal.
I installed both packages globally on my Windows 10 Device.
npm install forever -g
npm install -g nodemon
I tried using the following command to launch my app:
forever start nodemon --exitcrash app.js
However, I get the following error: "nodemon does not exist"
If try just running "nodemon" the application starts which indicates the Nodemon package is installed however, this will not allow the app to restart after a crash.
Am I doing something wrong? Most advice I find online is only relevant to Linux systems.
If you are already using forever, then you can get rid of nodemon. Instead you can use a combination of forever and cluster module. Simply fork the worker in case of exceptions, and it makes your app more scalable too!
If still nodemon is preferable, maybe try installing it globally using the -g flag
Forever and nodemon achieve 2 completely different objectives
nodemon is used to run your application in development mode, where you are frequently changing code, and need to restart the server .It will not restart your application in case of a crash. more about that later
Forever, on the other hand, is for making your application run as a daemon in production. And auto restart if you have uncaught exceptions.
Historically people have used Forever stand alone, or with upstart scripts, running as a linux service one of the most famous being upstart
Current norm is to use PM2
Related
I' ve created my node.js app with express, now i want to upload it on my local server machine.
I've created a bat file (I will use task planner to run this) that basically move to folder app and launch "npm run start".
The question is: There's a more correct way to this? (no cloud) and is it possible to hide the cmd window?
Putting a node.js application to production can be done with pm2. Pm2 will spin up your application and keep it alive, without having any terminal/cmd open.
Simply install pm2 globally on your machine:
$ npm install pm2 -g
Then launch your application with pm2:
$ pm2 start app.js
There are some configurations you could do, so I suggest you look at their repo
I installed Nodejs(v 10.16.0 LTS) and then using Windows Powershell I run following commands
npx create-react-app my-app
cd my-app
npm start
The actual problem I am facing is that if PowerShell window is opened in the background, then my code works properly. But when I close PowerShell and reload Browser Tab, the error occurs which say
This site can’t be reached
localhost refused to connect.
Try:
Checking the connection
Checking the proxy and the firewall.
Kindly help me to figure out this issue. Thanks
When you close PowerShell window you terminate your React app as well, it has to stay opened. Running npm start kicks off local server with your app running. If you want to have possibility to have application running with terminal closed you can use libs like https://www.npmjs.com/package/forever, but I do not recommend that- it's easy to forget you have one app instance running already :)
When you run the command npm start, this is the expected behaviour. This command spawns a new npm instance in the directory from where you have executed it and directs it to start a server. The catch here is that the server runs as an attached process with PowerShell, by default and it is bound to terminate once you close the PowerShell window.
To manually detach a process from the terminal, we use an & after the command on a UNIX-based system (Linux, MacOS etc.) something like npm start &.In case of PowerShell, you can make use of a built-in function called Start-Process like this -
Start-Process -NoNewWindow npm start
If you'd like to read more about it, you can refer a blog post here - https://ariefbayu.xyz/run-background-command-in-powershell-8ea86436684e
I am using Nodemon to speed up my development so it restarts my app when I do some changes.
As WebStorm debug is not working with Nodemon in standard way (%NODE_DEBUG% or --debug-brk does not trigger debugger properly), I found the way where I run nodemon --debug-brk and remote debugging session in WebStorm.
The issue which I got is that every time when nodemon restarts my app it hangs on (the app) until I will restart my remote debug and then it enters my entry JS file and then I can 'continue' and it works then. It is annoying and I have no idea how to set it up properly.
Is it either better way to set up Nodemon+WebStorm or somehow set WebStorm in a way when it will not loose connection to that debug session?
As WebStorm debug is not working with Nodemon in standard way
(%NODE_DEBUG% or --debug-brk does not trigger debugger properly)
WebStorm does allow debugging applications run with Nodemon using either Node.js
or NPM run configurations
The issue which I got is that every time when nodemon restarts my app
it hangs on (the app) until I will restart my remote debug and then it
enters my entry JS file and then I can 'continue' and it works then.
Known issue, WEB-25672
I'm doing small programming challenges locally.
In one tab I draft a solution, let's call it challenge.js and in another tab I run the command node challenge.js whenever I make a change.
Is there a way for node to compile automatically whenever a change has been made to challenge.js?
The first comment answered the question.
I installed nodemon:
$ npm install nodemon -g
$ nodemon app.js
and it works perfectly.
This is for development environment?
If yes, you can use a build tool like webpack, gulp, etc.
Webpack provides a tool webpack-dev-server, that recompile your bundle at every change.
I hope to have helped.
Use nodemon. https://www.npmjs.com/package/nodemon I work in server development and it refershes the server every time I save a file. If its a case you want something live to restart every time it crashes or if theres any change use pm2
https://www.npmjs.com/package/pm2
My NodeJs is working fine but i have an issue I'm not seeing $ in the prompt as most example point.
Another issue is when i put sudo I dont get anything.Things I have tried are the following
$ sudo npm install npm -g
/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js
npm#2.7.1 /usr/lib/node_modules/npm
given on the following Website
http://www.tutorialspoint.com/nodejs/nodejs_npm.htm
Apologies am very new to Node.JS.Please help
I'm going to explain this in terms familiar to MS windows.
$ npm --version
^ dollar sign is the same as "C:\" in windows.
It just means "from here..." in the most basic terms I can use.
You don't need the dollar sign for anything in that tutorial.
"sudo" means "elevate to an administrator level" similar to opening a command line terminal "in administrator mode." But for Linux (Ubuntu and Mac as *NIX) systems.
--version can be called as "-v" most of the time and means "for the thing I've named before, in this case "npm" show me the version.
Once you've installed NodeJS it comes with a "package manager" called NPM. The best way to relate this to windows is by considering it a command line version of an "installation" that installs different programs as you tell it to with different options.
"npm install -g" means "Hey NPM! Install to EVERYWHERE(call from command line/terminal/bash) the thing I Tell you next. "npm install -g express" for example, means hey NPM, install "expressJS" globally, so I can use the terminal to write commands(micro apps) from the expressJS I just installed with node.
"npm install --save" means hey, install this microapp, but ONLY let me use it in THIS EXACT FOLDER I'm in, and let anyone else that is in this folder know they need to install it to use this application I'm making.
"npm init" Is actually the FIRST thing you should do in any node project folder. It creates the "package.json" file in the current directory, and it will define the folder you're in as the folder to start installing stuff you "npm install" to the "node_modules" folder that will show in the folder you're currently in.
If you want to tinker with NodeJS code, and you don't want to tamper with your local machine and install all kinds of stuff you're not totally sure about yet you can use "REPL.it" (https://repl.it/languages/nodejs) the white window on the right is treated like a file you'd run in node. The dark window on the right is an actual NODE TERMINAL that you can run nodejs commands/code in directly.
There's one other good resources in general and that is here (https://devdocs.io/) it's called "Devdocs" and it has Node, npm, and express code examples, clean explanations, and examples that you can download directly to your local machine.
I hope that gets you moving with NodeJS. It's hard to understand, but with a bit of try and fail you'll start to try more and fail less. Cheers!