Timeout on subprocess readline in Python

Question

I have a small issue that I\'m not quite sure how to solve. Here is a minimal example:

What I have

scan_process = subprocess.Popen(command, stdout=su         


        

Answer 1

While Tom's solution works, using select() in the C idiom is more compact, this is the equivalent of your answer:

from select import select
scan_process = subprocess.Popen(command,
                                stdout=subprocess.PIPE,
                                stderr=subprocess.STDOUT,
                                bufsize=1)  # Line buffered
while some_criterium and not time_limit:
    poll_result = select([scan_process.stdout], [], [], time_limit)[0]

The rest is the same.

See pydoc select.select.

[Note: this is Unix-specific, as are some of the other answers.]

[Note 2: edited to add line buffering as per OP request]

[Note 3: the line buffering may not be reliable in all circumstances, leading to readline() blocking]