Counting the processes on linux in Golang

Issue

I am working on a plugin that can count the processes running on a Linux system. I have searched around and it seems that I need to access /proc and gather information from there. I also tried using the os, os/exec, and syscall packages to run the external command ps -A --no-headers | wc -l but this isn’t working either. I am coding this in golang as well. Any help or suggestions are welcome.

Solution

You can find the code that the Linux ps uses to iterate through the list of processes here:

https://gitlab.com/procps-ng/procps/blob/master/proc/readproc.c#L1167

In short, the algorithm is:

  1. opendir on /proc
  2. call readdir until an entry whose first character is a digit is returned.

So to count the number of processes, you can read through the entire directory and count how many entries match.

You can do this in Go using os.Open to open /proc, and then call the Readdirnames method to list the processes.

Answered By – James Henstridge

Answer Checked By – Robin (GoLangFix Admin)

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