from garcon import task


@task.decorate(timeout=7200)
def communicate(activity, pipe, mysql_stderr=None):
    """Communicate to pipe that there is no more inputs.

    The pipe will therefore start to read all inputs and write all outputs.

    Args:
        activity (ActivityWorker): The swf activity worker.
        pipe (Popen): Store pipe signal.
        mysql_stderr (io.TextIOWrapper): Tempfile with stderr of MySQL client
            subprocess.
    """
    if not pipe:
        raise Exception('Pipe does not exist')

    activity.logger.info('Start writing and reading all inputs and outputs')
    pipe.communicate()

    # catch exception from MySQL client subprocess, if open tempfile was passed
    if mysql_stderr:
        errors = ''
        mysql_stderr.seek(0)
        errors_and_warnings = mysql_stderr.readlines()
        for error_or_warning in errors_and_warnings:
            # we always get mysql warning about using creds in command line
            if 'ERROR' in error_or_warning:
                errors += error_or_warning  # catch only errors
        mysql_stderr.close()
        if errors:
            raise Exception(errors)

    activity.logger.info('All pipe tasks done.')