Killing a NodeJS Process
Background
When running a NodeJS application using node app.js or sudo node app.js through a ssh connection, the process will continue to run even after the ssh connection is closed. This can happen if the ssh application is closed, the ssh client computer falls asleep, or the network connection is lost. This can be a problem if you reconnect and try to run the same application again. You will get an error that looks similar the following:
pi@raspberrypi:~ $ sudo node app.js
node:events:491
throw er; // Unhandled 'error' event
^
Error: listen EADDRINUSE: address already in use :::5000
at Server.setupListenHandle [as _listen2] (node:net:1463:16)
at listenInCluster (node:net:1511:12)
at Server.listen (node:net:1599:7)
at Object.<anonymous> (/home/pi/app.js:867:10)
at Module._compile (node:internal/modules/cjs/loader:1191:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1245:10)
at Module.load (node:internal/modules/cjs/loader:1069:32)
at Function.Module._load (node:internal/modules/cjs/loader:904:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:22:47
Emitted 'error' event on Server instance at:
at emitErrorNT (node:net:1490:8)
at processTicksAndRejections (node:internal/process/task_queues:83:21) {
code: 'EADDRINUSE',
errno: -98,
syscall: 'listen',
address: '::',
port: 5000
}
Solution
TO kill the process, follow the steps below:
Run the following command to find the process ID (PID) of the process:
sudo lsof -i :PORTReplace PORT with the port number listed in the error message and run the command . For this example the port is 5000.
The output will look like the following:
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 12345 pi 3u IPv6 12345 0t0 TCP *:5000 (LISTEN)Kill the process using the PID
sudo kill -9 PIDReplace PID with the PID from the previous step and run the command. For this example the PID is 12345.
Once the process is killed, you can run the application without issues
Additional Information
The following commands may also be useful for depending on the situation:
kill -9 pid
killall -9 app-name
sudo kill -9 pid
sudo killall -9 app-name