Python sub-process with timeout

bash.py

from subprocess import PIPE, Popen
from signal import alarm, signal, SIGALRM, SIGKILL
import logging
from traceback import format_exception
import sys

class RuntimeException(Exception):
     pass

class Bash:
    def __init__(self, args, timeout=600):
        self.args = args
        logging.debug("execute:%s"%args)
        self.timeout = int(timeout)
        self.process = None
        self.success = False
        self.run()

    def run(self):
        class Alarm(Exception):
            pass
        def alarm_handler(signum, frame):
            raise Alarm

        try:
            self.process = Popen(self.args, shell=True, stdout=PIPE, stderr=PIPE)
            if self.timeout != -1:
                signal(SIGALRM, alarm_handler)
                alarm(self.timeout)

            try:
                self.stdout, self.stderr = self.process.communicate()
                if self.timeout != -1:
                    alarm(0)
            except Alarm:
                os.kill(self.process.pid, SIGKILL)
                raise  RuntimeException("Timeout during command execution")

            self.success = self.process.returncode == 0
        except:
            raise  RuntimeException(format_exception(*sys.exc_info()))

        if not self.success: 
            logging.debug("Failed to execute:" + self.get_err_msg())

    def is_success(self):
        return self.success
    
    def get_stdout(self):
        return self.stdout.strip("\n")
    
    def get_lines(self):
        return self.stdout.split("\n")

    def get_stderr(self):
        return self.stderr.strip("\n")
    
    def get_err_msg(self):
        if self.is_success():
            return ""
        
        if self.get_stderr() is None or self.get_stderr() == "":
            return self.get_stdout()
        else:
            return self.get_stderr()
            
            
if __name__ == '__main__':
  b = Bash('ls -al /etc/')
  b.get_lines()