I'm not a Node.js developer. So I have no idea how it works. I've been a PHP developer for over 8 years.
Because of some reason, I need to make a small change in a Node.js project which is live. All I have to do is changing a payment gateway token. I did it like this:
After pulling it on the server, users still go to the old payment gateway. So I guess I need to do a restart. (I'm saying so because, for PHP projects, when you change a config-related thing, you need to restart PHP).
Not sure should I restart what thing? Noted that, the server is Ubuntu 20.04 and uses Nginx to talk to Node.js. In other word, how can I see Node is running as what service on Linux?
Also, there are two files that I think I need to run the project again after restarting Node through one of them: index.js, server.js. Am I right?
And
Your Node.js script likely runs under a process that restarts the script in case it dies. There are several "run forever" wrappers, the most popular one is pm2. Find out which one is used in your project. Try pm2 list as the user your project executes under. If pm2 type pm2 restart app_name to restart your project.
Please check if it is a node.js project so you can write the command node index.js or node server.js with this command you can start your node server.
When creating a react app, I run these commands in my terminal:
npx create-react-app app-name
npm install
npm start
npm start allows me to view my project locally, but I accidently closed my terminal before running ctrl + c to end it. The browswer tab containing localhost 3000 (the npm start default host) has been closed for a while now, but my project can still be viewed there everytime I follow that link. Now everytime I run npm start it tells me that localhost 3000 is taken and I have to input another command and run it on localhost 3001. I've made this mistake a few times. I don't mind doing this, but it got me wondering if there is a global version of ctrl + c that will close all of these at once.
Firstly, I think you've had a misconceptions here: closing the browser tab will never end the server that you've started (i.e. the server npm start created).
For your question I think you can use the approach of killing a process based on the port they're occupying in this question:
Find (and kill) process locking port 3000 on Mac
I keep on getting "? Something is already running on port 3000" message in my terminal when I start up my react server when there is absolutely nothing running on my port 3000
What I have tried to solve with:
Restart the macOS.
checking my "http://localhost:3000" on chrome browser. (Nothing: This site can’t be reached)
Go to chrome://serviceworker-internals and chrome://appcache-internals, search for localhost:3000 (Nothing found)
I also tried almost every command lines I found on Google regarding this issue
I also created another express.js app, and it was successfully launch on port 3000 while React said there is something running on 3000. React on my computer just keeping thinking there is something running on port 3000.
If you are a windows user you can try using
npx kill-port 3000
in your console. I was having the same problem and it worked for me.
Not sure about MAC.
Open cmd and write this
netstat -a -o -n
You will get list of active connections then find 3000 by hitting
Cntrl + f
Copy the PID of that port and hit this command
taskkill /F /PID PID_of_port
Edit
This guide is for windows.
Kill Node.Js process from Task Manager.
Step 1: Open Task Manager by clicking ctrl+shift+delete
Step 2: Open Prcesses tab
Step 3: Search for Node.JS process and right click on that then click on End Task
Step 4: Now you can start again.
As #khurram khan suggested terminating the process may be the best option for you, This work for me on linux:
$ lsof -i tcp:3000
$ kill -9 PID
the first command should give you the PID number to enter in the second command as PID.
I had this problem on Mac and I solved by running:
npx kill-port 3000
I had stuck with this one for few hours, and the end I had found the solution
There was incorrect mapping to the local host in the hosts file and didn't had any relation to the port taken something like
10.2.224.130 localhost
Just Change it back to
127.0.0.1 localhost
Host file locations
https://www.howtogeek.com/howto/27350/beginner-geek-how-to-edit-your-hosts-file/
In case anyone comes across this and the above solutions didn't help, make sure your /etc/hosts has:
127.0.0.1 localhost
For some reason this was wiped from my hosts file and CRA's dependency for checking ports (detect-port-alt) checks localhost:[PORT] to see if it's available. If it errors out, you'll always get the "Something is already running..." error when checking a specific port but not when using a random port (since that's picked by the dependency).
kill node.js from the background processes. that would soleve the probelem. alterntively, you could restart your system
for window use this in package.json
"start": "set PORT=3006 && react-scripts start"
for Linux and MacOS
"start": "PORT=3006 react-scripts start"
This worked for me on windows pc. This one is for those are not seeing the port when you run this command netstat -a -o -n on your command prompt.
Open your command prompt in administrator mode and run this command
net stop winnat
you'll get this response:
The Windows NAT Driver service was stopped successfully.
Them you run this next:
net start winnat
then you will get this response:
The Windows NAT Driver service was started successfully.
once you do that. Start the react server and it would work. Same too if your backend server doesn't run on 3000
It's very simple. You can fix it in 2 easy steps.
Check your environment variables if there is a key/entry with name "PORT".
If found delete that entry or rename it to something else.
It turns out that some other program is using that variable. Usually when you start react-scripts it will look for an environment variable with that title PORT.
Date: Sat 07, October 2020
Windows: Microsoft Windows 10 Pro Build 19041
Node: 12.16.1
NPM: 6.14.8
Something similar was happening to me on my Windows machine. Tried a lot of things suggested here on StackOverflow and other places.
In my case, I was following a video course that was suggesting adding --script-version 1.1.5 (as illustrated below) when creating a new React app.
create-react-app app-name --scripts-version 1.1.5
Here's the package.json scripts versions:
React: 17.0.1
React DOM: 17.0.1
React Scripts: 1.1.5
After running the command npm start and typing y to try to use a different port, the terminal will stay stucked until it was canceled.
Then I created a new React app without --scripts-version 1.1.5 and after trying to running it, it was still running into Something is already running on port 3000 but after typing y, the app will run with no problem on a different port.
Here's the package.json scripts versions (when it was running successfully):
React: 17.0.1
React-Dom: 17.0.1
React-Scripts: 4.0.0
Starting with the reason you do not see anything on localhost:3000, is because there must be a proper webapp or a website/server running on that port, but the port:3000 is currently running some process, just not of a server/site/app.
This out of the way, depending on your type of OS, it is quite easy to check if there is in-fact a process on port:3000 or not. For MacOS, opening a terminal and running sudo lsof -i ':3000' will list the current process on port 3000.
Note that we need to run command as sudo or root
Once you see what process is running, note the PID and run kill -9 {PID}, which should kill the process with PID (i.e distruptive process on port:3000). Now doing a npm start should get your app built, compiled and served on localhost:3000
Mostly what might've happened is that you had a npm start running which you either interrupted, or closed in the foreground. Doing a fg in your terminal will open any background tasks, so if this opens a npm start instance, it was this process stopping your flow. You can then properly end the session making sure all processes on port:3000 are killed.
Happy coding
If you are on linux you can try
pkill -f node
to terminate the processs
The error occurs when a task is left running on the port properly killing it.
this error can occur on both ports. Your react app and your node server.
To solve this you can run the following commands.
netstat -anp tcp | grep 3000
This command in the terminal will give you the list of activities on port 3000
npx kill-port 3000
This command will kill all the running servers on port 3000.
Now if you have the same problem for your Node server. You can follow the same steps.
netstat -anp tcp | grep 5000
Then
npx kill-port 5000
You don't need the first command. it's just to list out the running activities on the port.
just change the port number for any other port number.
This is the output you get after running the commands.
I am using Git bash on windows.
For me, this works every time (macOS): sudo kill -9 $(sudo lsof -t -i:3000)
Simple and Easy solution
close your current terminal and open a new one.
If you are running it in VS Code just create a new terminal and delete the old one.
On React - you can run an already created React single-page application (SPA) by
npm start command.
That may start your locally hosting development server and runs your app at:
http://localhost:3000/ which is equivalent to: 127.0.0.1:3000 address
127.0.0.1 is the default localhost IP number while the default port number set by
create-react-app package is 3000.
When getting: “Something is already running on port 3000" failure error message you may think that the port captured by another process running on your machine but you’ll find that it is captured permanently as if it runs on 0.0.0.0:3000 address
Solution:
In your project libraries created by create-react-app script navigate to:
node_modules/react-scripts/scripts/start.js
While running npm start command - the start.js script is being called and executed
There at start.js file in you editor find the above line:
const HOST = process.env.HOST || '0.0.0.0';
and change it to:
const HOST = process.env.HOST || '127.0.0.1';
save and run your web app again at: http://localhost:3000/ or http://127.0.0.1:3000
I inherited a project where the person wrote tools to test our site's UI using JQuery and JS.
I don't know too much about it other than it requires a browser to be spawned and I think the tool uses JS to interact with iframes to see if it's the expected values.
My job is to get this tool to run on a remote server and post the results to Jenkins.
The remote test server and staging server is linux. From our staging server, I want to write a script to spawn a browser and run cmds from the tool to test our UI. I ran the following manually:
ssh -X user#remote_test_server /usr/bin/firefox
However, the remote server says:
Error: no display specified
Is there a way to spawn a browser for automated testing from one headless server to another? Thanks in advance for your help.
I faced a similar problem when I tried to automate a GUI installation program. While there are quite some different possibilities to choose from (e.g. Xnest, Xephyr?), I ended up using vncserver, because it's relatively easy to debug the GUI session this way.
You need to create a vncpassword file, I think:
mkdir -p $HOME/.vnc
chmod 0700 $HOME/.vnc
echo MyLittlePassword | vncpasswd -f > $HOME/.vnc/passwd
chmod 0600 $HOME/.vnc/passwd
Starting the server is then quite straightforward
vncserver
export DISPLAY=:1
/usr/bin/firefox&
...
Now it is possible to connect to the VNC server with a VNC viewer of your choice. But beware there may be no window manager, depending on the X startup scripts of your environment.
Shutting the server down
vncserver -kill :1
In the configuration of Jenkins project , specify the
Build Environment
Start Xvfb before the build, and shut it down after.
#
I have setup a test of a Node.js server but how is the server best launched?
My strategy for now is to use cluster (http://learnboost.github.com/cluster/). This mostly works really nice. I have the following setup in my app.js file (created with express):
cluster(app)
.use(cluster.reload())
.use(cluster.reload('views', {extensions: ['.js', '.ejs']}))
.use(cluster.logger('logs'))
.use(cluster.stats())
.use(cluster.repl('/Users/testuser/work/1test/test.sock'))
.use(cluster.debug())
.use(cluster.pidfiles())
.use(cluster.cli())
.listen(3000);
It works on my Mac when i test locally. I launch it with the command
nohup node app.js &
But when I run on Linux and detach from the terminal the master dies - the working threads are still working. On the Mac it runs even when I close the terminal.
I read that it might be necessary to change the user, this can apparently be done in cluster with:
.set('user', 'rambo')
Does anyone have a "best practice" for launching node.js as a "Daemon" with cluster so you can detach the terminal?
If I change the user who should I be logged in as when I launch?
Should I use a program such as screen to detach from the terminal without killing any processes?
try forever.
npm install -g forever
https://github.com/indexzero/forever
Looks like you're also setting
.use(cluster.repl('/Users/testuser/work/1test/test.sock'))
which probably doesn't exist on your linux server.