Python script to run two processes simultaneously

Question

I am using python script with multiprocessing module to run 2 processes at the same time. Each process takes 4-5 minutes to complete. I am not able to run both process simultaneously. Below is my script.

My script run on server C and it takes two arguments as IP addresses and takes MTR from server A & B. A---->B & B----->A. This should happen at the same time.

 import paramiko
 import os
 import argparse
 from multiprocessing import Process, Queue, Lock
 parser = argparse.ArgumentParser()
 parser.add_argument("ip1", help="Input the Source IP Address: ")
 parser.add_argument("ip2", help="Input the Destination IP Address: ")
 args = parser.parse_args()
 class Myssh:
 def __init__(self, iph, ipd):
 self.iph = iph
 self.ipd = ipd
 self.cmd = "mtr --no-dns -rwc 300 %s" % ipd
 def do(self):
 count = 1
 print "Starting Thread"
 client = paramiko.SSHClient()
 client.set_missing_host_key_policy(paramiko.WarningPolicy())
 client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
 key = os.path.expanduser(r'/home/rsharma/master004_rsa')
 privkey = paramiko.RSAKey.from_private_key_file(key)
 client.connect(self.iph, port=12001, username="master", pkey=privkey, look_for_keys=False)
 stdin, stdout, stderr = client.exec_command(self.cmd)
 for line in stdout:
 print '...' + line.strip('\n')
 client.close()
 if __name__ == "__main__":
 lock = Lock()
 s1 = Myssh(args.ip1, args.ip2)
 s2 = Myssh(args.ip2, args.ip1)
 p1 = Process(target=s1.do())
 p1.start()
 p2 = Process(target=s2.do())
 p2.start()
 p1.join()
 p2.join()

• Rohit_Sharma: Right now, my script is executing both processes sequentially not in parallel. I want it to run both commands in parallel and complete in 5 minutes inspite of 10 minutes.
• Vincent Savard: @timlyo If you edit indentation (and you really shouldn't in most of the cases), at least make sure you don't change the intent of the code. It's a shame this was approved by reviewers who pay no attention.

Answer 1

This code is saying run the function, and set what it returns as the process target. You need to change these lines

p1 = Process(target=s1.do())
p2 = Process(target=s2.do())

to

p1 = Process(target=s1.do)
p2 = Process(target=s2.do)

The brackets after the function are running it there and then.

• Rohit_Sharma: Thanks for the answer. I am not getting any error due to indentation. Please clarify your comment on indentation in my script.
• timlyo: The error isn't from the indentation. I was simply trying to format the code in your answer so that it looked better. You need to remove the brackets after the s1.do in your code. See my answer.