Reading/writing stdout/stdin

run_test_robot.py

import os, psutil, subprocess
# Usage:
# This script MUST be run from the root of the 
# teraview-test-robot directory for example using,
#     python run_test_robot_cmd.py


def make_test_robot_process():
    """Creates the test robot process."""
    REL_TEST_ROBOT_EXE = "bin\\Debug\\test-robot.exe"
    REL_CONFIG = "config\\test2"
    setup_args = [REL_TEST_ROBOT_EXE, REL_CONFIG]
    #print setup_args
    p = subprocess.Popen(setup_args,
                         stdout=subprocess.PIPE, stdin=subprocess.PIPE)
    # this works but closes the pipe!
    #print p.communicate('show')
    return p

p = make_test_robot_process()

EOL = "\r\n"
#print "{}Test Robot is ready for commands e.g. type 'help' or 'show' to start.{}".format(EOL, EOL)

# Start command loop
while True:

    # Wait for user input
    s = raw_input("> ")
    # Append end-of-line
    cmd_str = "{}{}".format(s.strip(), EOL)

    # Do we need to flush before sending?
    p.stdin.flush()
    p.stdout.flush()

    # Write command to stdin
    p.stdin.write(cmd_str)
    import time; time.sleep(0.3)
    print "Send command '{}' now reading lines... this will probably hang...".format(cmd_str.strip())

    # Print debug values because this is not working...
    print p
    print p.stdout

    # This line hangs! Grrr
    response = p.stdout.readline()

    # Do something with the response
    if response != '': 
        print "{}".format(response)
    else:
        print "Breaking out"
        break