python pipe only stdin,out once, how to do twice or more time

Question

success python pipe stdin, out only one time this source

main.py

import subprocess from subprocess import PIPE, STDOUT

player_pipe = subprocess.Popen(["source\call.py", 'arg1'], stdin=PIPE,
     stdout=PIPE, stderr=STDOUT, shell=True)

player_pipe.stdin.write("Send Msg\n")
get_stdout = player_pipe.stdout.readline()
print("[Get Msg]" + get_stdout)

player_pipe.kill()
player_pipe.wait()

call.py

import sys

getMsg = raw_input()
print getMsg

but I want twice or more time stdin, out

so update source but it's not work

What's wrong this source

main.py (update-not work)

import subprocess from subprocess import PIPE, STDOUT

player_pipe = subprocess.Popen(["source\call.py", 'arg1'], stdin=PIPE,
     stdout=PIPE, stderr=STDOUT, shell=True)

player_pipe.stdin.write("Send Msg\n")
get_stdout = player_pipe.stdout.readline()
print("[Get Msg]" + get_stdout)

player_pipe.stdin.write("Send Msg2\n")
get_stdout = player_pipe.stdout.readline()
print("[Get Msg]" + get_stdout)

player_pipe.kill()
player_pipe.wait()

call.py(update-not work)

import sys

getMsg = raw_input()
print getMsg

getMsg2 = raw_input()
print getMsg2

:D

Answer 1

the output of call.py is buffered. so you have to flush() it to send to main.py.

#!/usr/bin/python2
import sys

getMsg = raw_input()
print getMsg
sys.stdout.flush()

getMsg2 = raw_input()
print getMsg2
sys.stdout.flush()

Note that you need shebang #!/usr/bin/python2 at least when your OS is Linux (I don't know why OP's code works without shebang. Maybe some Windows magic ?).

Also you can use -u option not to buffer the output of python.

player_pipe = subprocess.Popen(["/usr/bin/python2","-u","./call.py"], stdin=PIPE,
     stdout=PIPE, stderr=STDOUT, shell=False)