stdio_log.py

import subprocess
import sys
import threading

def log_and_forward(input_stream, output_stream, log_file, direction):
    """
    Reads from the input stream, writes to the output stream, and logs data.

    Args:
        input_stream: Stream to read data from (e.g., stdin of the user).
        output_stream: Stream to write data to (e.g., stdin or stdout of the process).
        log_file: File object to write logs to.
        direction: Direction of traffic (e.g., 'stdin->process' or 'process->stdout').
    """
    while True:
        data = input_stream.readline()
        if not data:
            break
        log_file.write(f"[{direction}] {data}")
        log_file.flush()
        output_stream.write(data)
        output_stream.flush()

def main():
    if len(sys.argv) < 2:
        print("Usage: python log_stdio.py <command>")
        sys.exit(1)

    command = sys.argv[1:]  # Command and its arguments
    log_file_path = "traffic.log"

    with open(log_file_path, "w") as log_file:
        # Start the subprocess with pipes for stdin, stdout, and stderr
        process = subprocess.Popen(
            command,
            stdin=subprocess.PIPE,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,  # Log stderr along with stdout
            text=True,  # Use text mode
            bufsize=1  # Line-buffered for interactive output
        )

        # Start threads to handle stdin and stdout
        stdin_thread = threading.Thread(
            target=log_and_forward,
            args=(sys.stdin, process.stdin, log_file, "stdin->process"),
            daemon=True
        )
        stdout_thread = threading.Thread(
            target=log_and_forward,
            args=(process.stdout, sys.stdout, log_file, "process->stdout"),
            daemon=True
        )

        # Start the threads
        stdin_thread.start()
        stdout_thread.start()

        # Wait for the process to complete
        process.wait()

        # Wait for threads to finish
        stdin_thread.join()
        stdout_thread.join()

if __name__ == "__main__":
    main()