Cannot attach to second node process by using SIGUSR1

[aldafu]

• Version: 6.12.3 +
• Platform: Win 10 x64 / Linux 4.x
• Subsystem:

Suppose I have two or more running node processes which are not in debugging mode and I want to activate the debugger in these processes. By using SIGUSR1 or process._debugProcess() the process starts listening on the default port 5858 for the debugging client. All node processes after the first that receive SIGUSR1 will fail to take port 5858 and thus cannot be debugged while already running.

Worse, if you use node debug -p $PID_OF_SECOND_PROCESS the debugger will attach to the first node process that was able to take port 5858 instead of the PID given on the command-line.

Is there any way to change the default debugging port for an already running node process, so I can attach to that?

[bnoordhuis]

Start node with --inspect-port=0 to bind to a random port or set process.debugPort to the desired port number.

process.debugPort should be documented. I've added labels. Could use a note in doc/api/process.md and doc/api/debugger.md.

[juggernaut451]

can i take this up @bnoordhuis ?
It would be my first contribution

[aldafu]

This is about already running processes, so I don't think --inspect-port=0 or process.debugPort are valid options, right? How configure that port once the process is already running?

[bnoordhuis]

As long as the inspector hasn't been started yet, you can configure the port with process.debugPort.