How to execute a non-blocking script in python and get its return code?

Question

I am trying to execute a non-blocking bash script from python and to get its return code. Here is my function so far:

def run_bash_script(script_fullname, logfile):
 my_cmd = ". " + script_fullname + " >" + logfile +" 2>&1"
 p = subprocess.Popen(my_cmd, shell=True)
 os.waitpid(p.pid, 0)
 print(p.returncode)

As you can see, all the output is redirected into a log file, which I can monitor while the bash process is running.

However, the last command just returns 'None' instead of a useful exit code.

What am I doing wrong here?

Answer 1

You should use p.wait() rather than os.waitpid(). os.waitpid() is a low level api and it knows nothing about the Popen object so it could not touch p.

• Alex: Thanks, it looks like that was exactly what I needed!