- 1 year ago
subprocess Popen stdin will only input and run after the script has finished
The behavior you described, where the input provided to subprocess.Popen
is not processed until the script has finished, is likely due to buffering. By default, the standard input (stdin) stream is line-buffered, meaning that the input is buffered until a newline character is encountered.
To overcome this buffering issue and allow the input to be processed immediately, you can disable buffering for the stdin stream. Here's an example:
pythonimport subprocess
# Start the subprocess
process = subprocess.Popen(['python', 'your_script.py'], stdin=subprocess.PIPE, bufsize=0)
# Send input to the subprocess
process.stdin.write(b'Your input\n')
process.stdin.flush()
# Wait for the subprocess to finish
process.wait()
In this example, the bufsize=0
argument is passed to subprocess.Popen
to disable buffering for stdin. Additionally, after writing to the stdin stream using process.stdin.write()
, we call process.stdin.flush()
to ensure the input is immediately sent to the subprocess.
By disabling buffering and flushing the stdin stream, the input provided to the subprocess should be processed immediately rather than waiting for the script to finish.