op.pla subprocess logging

subprocess_log.py

"""
Optimize saving the stdout of a subprocess.
"""
import os
import subprocess
import sys
import io


def run_command(cmd, log_file_path, timeout=28800, timeout_rerun=3):
    """
    Runs the input command via subprocess module with a default timeout of 8 hours.
    """
    def write_log(log):
        """Appends the input to the log file."""
        with open(log_file_path, "a") as f:
            f.write(log)

    try:
        process = subprocess.run(
            cmd,
            shell=False,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            timeout=timeout,
            universal_newlines=True)

        write_log(process.stdout)

        return process

    except subprocess.CalledProcessError as cmdError:
        write_log(cmdError.stdout)
        write_log(str(cmdError))
        return process

    except subprocess.TimeoutExpired as cmdTimeout:
        write_log(cmdTimeout.stdout)
        write_log(str(cmdTimeout))

        # relaunch the command after timeout.
        if timeout_rerun > 0:
            write_log("\n\n###########\nRELAUNCH AFTER TIMEOUT\n###########\n\n")

            # recursive call in which the "timeout_rerun" arg is used as a counter.
            rerun_count = timeout_rerun - 1
            process = run_command(cmd, log_file_path,
                                  timeout, timeout_rerun=rerun_count)
            return process
        else:
            write_log("\n\n###########\nTOO MANY TIMEOUTS\n###########\n\n")
            raise Exception("Too many timeouts")


if __name__ == "__main__":
    log_file_path = "test_log.txt"
    # remove old log file.
    if os.path.isfile(log_file_path):
        os.remove(log_file_path)

    # run the command and check if the return code is not 0.
    try:
        cmd_result = run_command(
            ["python3", "cmd_writer.py"], log_file_path, timeout=10)
        if cmd_result.returncode != 0:
            with open(log_file_path, "a") as log_file:
                log_file.write(
                    f"Unexpected Return Code: {cmd_result.returncode}")
            raise Exception()
    except Exception:
        sys.exit(1)