Question

I am trying to run a shell from my python program.
I have used a mltithreaded approach where an input from user is accepted and should be executed via the shell.

Everything seems right, except that the program execution just doesn’t take place beyond stdin.

I am not sure if there is something wrong with the way I have used Popen.stdin.

So please help on what is wrong here.

from subprocess import Popen,PIPE
import shlex
import threading
from Queue import Queue


class MyThread(threading.Thread):
    def __init__(self,func,args):
        threading.Thread.__init__(self)
        self.func=func
        self.args=args

    def run(self):
        apply(self.func,self.args)



def bash(command,output):
    commandList=shlex.split('python test.py')   
    process=Popen(commandList,stdout=PIPE,stdin=PIPE,stderr=PIPE,shell=True)
    print process.stdout.readlines()
    while (process.pole()==None):
        #commandList=shlex.split(command.get(1))
        print 'bash'
        process.stdin.write(command.get(1))
        process.stdin.flush()
        output.put(process.stdout.readlines(),1)
        process.stdout.flush()



def communicate(command,output):
    while True:
        command.put(raw_input('enter command>'))
        print 'communicate'
        print output.get(1)



funcs=[bash,communicate]
nfuncs=len(funcs)    

def main():

    command=Queue(1)
    output=Queue(1)
    threads=[]

    for i in range(nfuncs):
        t=MyThread(funcs[i],(command,output))
        threads.append(t)

    for i in range(nfuncs):
        threads[i].start()

    for i in range(nfuncs):
        threads[i].join()

    print 'successful'       

if __name__=='__main__':
    main()

I have given the output below.

karthik@ubuntu:~/TerminalChatBot/test$ python threadTerminal.py
enter command>ls
communicate

After this there is no execution. I can’t even use ctrl+c to stop the python script. It just hangs.

NOTE: the thread communicate needs to be there as we need to integrate this code with the bigger module.

Answer 1

Minor things:

It’s process.poll() not process.pole().

Instead of

 for i in range(nfuncs):
    t=MyThread(funcs[i],(command,output))
    threads.append(t)

do

 for func in nfuncs:
    t=MyThread(func,(command,output))
    threads.append(t)

Now, why are you running python test.py? Don’t you want to run ls communicate in a shell, in which case you should be doing something like:

def bash(command,output):
    process=Popen('bash',stdout=PIPE,stdin=PIPE,stderr=PIPE,shell=True)
    print process.stdout.readlines()
    # I don't really understand what's going on here
    while (process.pole()==None):
        print 'bash'
        process.stdin.write(command.get(1))
        process.stdin.flush()
        output.put(process.stdout.readlines(),1)
        process.stdout.flush()