Mixing
Sending SIGINT to process launched from Python does not yield same result as when process is launched from...
I am writing a script that is supposed to launch an interactive shell of a third-party program from within python in linux (the third party program is Stata). The purpose of the script is to control the stdin and stdout of the interactive shell so I can access it from an editor and other scripts.
When started from within a linux shell, Stata launches an interactive shell where you can run Stata commands. When I press control+C or use some other way to send a SIGINT signal to Stata, it will stop executing the current command and will return to the interactive shell, but it will not kill the Stata process. I want to replicate this behavior for Stata launched from python.
When I send a SIGINT signal to a Stata process launched from python, it will kill the process instead of just stopping execution of the current command.
The behavior in the shell is:
> /usr/local/stata14/stata
(...other stuff...)
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
(I hit CTRL+C)
--Break--
r(1);
.
The following python program launches Stata from within python:
def handler(signum, frame):
stata.send_signal(signal.SIGINT)
signal.signal(signal.SIGINT, handler)
stata = subprocess.Popen(["/usr/local/stata14/stata"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, preexec_fn=os.setpgrp)
(... other stuff hat handles forwarding stata.stdout to sys.stdout in a separate thread...)
while true:
time.sleep(0.1)
userinput = raw_input(". ")
print(userinput, file=stata.stdin)
stata.stdin.flush()
print(stata.poll())
with the same for loop running in the subprocess, produces:
> /usr/local/stata14/stata
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
-2
-2
-2
and any further attempt to write to stata.stdin then produces
print(userinput, file=stata.stdin)
IOError: [Errno 32] Broken pipe
Anyone understands why this is happening? I already tried using subprocess.Popen with shell = True. In this case, Popen launches an sh process and a Stata process. If I send SIGINT to the sh process, nothing happens. If I send it to Stata, the same problem as with shell=False arises.
Thanks in advance.
python linux signals sh
asked Nov 19 '18 at 12:33
Tobias
316315
add a comment |
I am writing a script that is supposed to launch an interactive shell of a third-party program from within python in linux (the third party program is Stata). The purpose of the script is to control the stdin and stdout of the interactive shell so I can access it from an editor and other scripts.
When started from within a linux shell, Stata launches an interactive shell where you can run Stata commands. When I press control+C or use some other way to send a SIGINT signal to Stata, it will stop executing the current command and will return to the interactive shell, but it will not kill the Stata process. I want to replicate this behavior for Stata launched from python.
When I send a SIGINT signal to a Stata process launched from python, it will kill the process instead of just stopping execution of the current command.
The behavior in the shell is:
> /usr/local/stata14/stata
(...other stuff...)
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
(I hit CTRL+C)
--Break--
r(1);
.
The following python program launches Stata from within python:
def handler(signum, frame):
stata.send_signal(signal.SIGINT)
signal.signal(signal.SIGINT, handler)
stata = subprocess.Popen(["/usr/local/stata14/stata"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, preexec_fn=os.setpgrp)
(... other stuff hat handles forwarding stata.stdout to sys.stdout in a separate thread...)
while true:
time.sleep(0.1)
userinput = raw_input(". ")
print(userinput, file=stata.stdin)
stata.stdin.flush()
print(stata.poll())
with the same for loop running in the subprocess, produces:
> /usr/local/stata14/stata
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
-2
-2
-2
and any further attempt to write to stata.stdin then produces
print(userinput, file=stata.stdin)
IOError: [Errno 32] Broken pipe
Anyone understands why this is happening? I already tried using subprocess.Popen with shell = True. In this case, Popen launches an sh process and a Stata process. If I send SIGINT to the sh process, nothing happens. If I send it to Stata, the same problem as with shell=False arises.
Thanks in advance.
python linux signals sh
asked Nov 19 '18 at 12:33
Tobias
316315
If you usekill -intinstead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.
– that other guy
Nov 19 '18 at 12:36
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50
add a comment |
I am writing a script that is supposed to launch an interactive shell of a third-party program from within python in linux (the third party program is Stata). The purpose of the script is to control the stdin and stdout of the interactive shell so I can access it from an editor and other scripts.
When started from within a linux shell, Stata launches an interactive shell where you can run Stata commands. When I press control+C or use some other way to send a SIGINT signal to Stata, it will stop executing the current command and will return to the interactive shell, but it will not kill the Stata process. I want to replicate this behavior for Stata launched from python.
When I send a SIGINT signal to a Stata process launched from python, it will kill the process instead of just stopping execution of the current command.
The behavior in the shell is:
> /usr/local/stata14/stata
(...other stuff...)
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
(I hit CTRL+C)
--Break--
r(1);
.
The following python program launches Stata from within python:
def handler(signum, frame):
stata.send_signal(signal.SIGINT)
signal.signal(signal.SIGINT, handler)
stata = subprocess.Popen(["/usr/local/stata14/stata"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, preexec_fn=os.setpgrp)
(... other stuff hat handles forwarding stata.stdout to sys.stdout in a separate thread...)
while true:
time.sleep(0.1)
userinput = raw_input(". ")
print(userinput, file=stata.stdin)
stata.stdin.flush()
print(stata.poll())
with the same for loop running in the subprocess, produces:
> /usr/local/stata14/stata
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
-2
-2
-2
and any further attempt to write to stata.stdin then produces
print(userinput, file=stata.stdin)
IOError: [Errno 32] Broken pipe
Anyone understands why this is happening? I already tried using subprocess.Popen with shell = True. In this case, Popen launches an sh process and a Stata process. If I send SIGINT to the sh process, nothing happens. If I send it to Stata, the same problem as with shell=False arises.
Thanks in advance.
python linux signals sh
asked Nov 19 '18 at 12:33
Tobias
316315
I am writing a script that is supposed to launch an interactive shell of a third-party program from within python in linux (the third party program is Stata). The purpose of the script is to control the stdin and stdout of the interactive shell so I can access it from an editor and other scripts.
When started from within a linux shell, Stata launches an interactive shell where you can run Stata commands. When I press control+C or use some other way to send a SIGINT signal to Stata, it will stop executing the current command and will return to the interactive shell, but it will not kill the Stata process. I want to replicate this behavior for Stata launched from python.
When I send a SIGINT signal to a Stata process launched from python, it will kill the process instead of just stopping execution of the current command.
The behavior in the shell is:
> /usr/local/stata14/stata
(...other stuff...)
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
(I hit CTRL+C)
--Break--
r(1);
.
The following python program launches Stata from within python:
def handler(signum, frame):
stata.send_signal(signal.SIGINT)
signal.signal(signal.SIGINT, handler)
stata = subprocess.Popen(["/usr/local/stata14/stata"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, preexec_fn=os.setpgrp)
(... other stuff hat handles forwarding stata.stdout to sys.stdout in a separate thread...)
while true:
time.sleep(0.1)
userinput = raw_input(". ")
print(userinput, file=stata.stdin)
stata.stdin.flush()
print(stata.poll())
with the same for loop running in the subprocess, produces:
> /usr/local/stata14/stata
. forval i = 1/100000 {
2. sleep 10
3. di "`i'"
4. }
1
2
3
4
-2
-2
-2
and any further attempt to write to stata.stdin then produces
print(userinput, file=stata.stdin)
IOError: [Errno 32] Broken pipe
Anyone understands why this is happening? I already tried using subprocess.Popen with shell = True. In this case, Popen launches an sh process and a Stata process. If I send SIGINT to the sh process, nothing happens. If I send it to Stata, the same problem as with shell=False arises.
Thanks in advance.
python linux signals sh
python linux signals sh
asked Nov 19 '18 at 12:33
Tobias
316315
asked Nov 19 '18 at 12:33
Tobias
316315
asked Nov 19 '18 at 12:33
Tobias
316315
asked Nov 19 '18 at 12:33
Tobias
316315
asked Nov 19 '18 at 12:33
Tobias
316315
316315
If you usekill -intinstead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.
– that other guy
Nov 19 '18 at 12:36
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50
add a comment |
If you usekill -intinstead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.
– that other guy
Nov 19 '18 at 12:36
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50
If you use
kill -int instead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.– that other guy
Nov 19 '18 at 12:36
If you use
kill -int instead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.– that other guy
Nov 19 '18 at 12:36
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50
add a comment |
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If you use
kill -intinstead to simulate what your doing from Python, you'll see the same behavior. Ctrl+C will send sigint to the entire foreground process group.– that other guy
Nov 19 '18 at 12:36
I put the subprocess in a different group using preexec_fn=os.setpgrp (hard to spot because the code above does not wrap lines). But it's true that I do observe the same behavior when I use kill -int on the process launched from python. Anyways: how can I replicate the behavior of the process launched without python for the process launched in python?
– Tobias
Nov 19 '18 at 12:44
Apparently the underlying program just acts differently when it is run in a terminal. So I solved this using pty.fork() instead of subprocess.
– Tobias
Nov 20 '18 at 20:50