I am trying to open and close an application sequentially. But the problem is the application is being opened but to enter to the next line which is the closing line of that application I have to manually close the application.
import os
os.system("scad3 file.txt")
os.system("TASKKILL /PID scad3.exe /T")
scad3 is the application i wish to run,but to enter the next line i.e., taskkilling line, I have to manually close the window
please let me know is there any way to solve it??
thank you very much in advance
I guess os.system is a blocking call. Try using the Popen Objects in python:-
import subprocess
p = subprocess.Popen("notepad.exe")
p.terminate()
Refer :https://docs.python.org/2/library/subprocess.html#popen-objects
You can try using popen to execute command then wait given time and try to get result or kill the subrocess if it hasn't finished.
import subprocess
def get_array_from_cmd_str(cmd_str):
cmd_str_parts = cmd_str.split(" ")
return [cmd_part for cmd_part in cmd_str_parts]
def run_command_str(command):
p = subprocess.Popen(get_array_from_cmd_str(command),
stdout = subprocess.PIPE, stderr = subprocess.PIPE).communicate()[0]
resp = {'out': p[0],
'err': p[1]}
return resp
to run a command use the "run_command_str" function above in this way:
import time
cmd = "scad3 file.txt"
cmd_out = run_command_str(cmd)
expected_execution_time = 5
time.sleep(expected_execution_time)
if cmd_out['err'] != '':
pass # handle error here
Now if your program does not close automatically you can modify the approach to manually kill it using methods descriged in this thread.
(examples not tested on Windows)
EDIT: Code modified according to valuable comment. Example makes a blocking call and does not address the issue; use other ones.
Related
I want to capture an output in python.
My code:-
import os
import sys
import subprocess
import time
cmd = './abc'
proc = subprocess.Popen(cmd)
time.sleep(12)
stdoutOrigin=sys.stdout
sys.stdout = open("log.txt", "w")
sys.stdout.close()
sys.stdout=stdoutOrigin
proc.terminate()
Problem is it never comes out of ./abc and is always stuck there. I need kill the process .
Normally i have to give CTRL+C to come out of it.
In this case how can i capture the output and save in a file which comes every 30 seconds .I need to capture it once.
You can redirect the output of a subprocess when starting it. Consider the following:
with open('proc.out', 'w') as proc_out:
subprocess.run(cmd, stdout=proc_out)
The call to run is blocking, but all the output is written to the output file. Once your subprocess finished, so does your Python script. You can still kill it prematurely, however.
Ok i found the answer and since Using only timeout would throw error
what i did was i added it to try and expect block.
import os
import sys
import subprocess
import time
cmd = './abc'
try:
with open('proc.out', 'w') as proc_out:
subprocess.run(cmd, stdout=proc_out , timeout = 30)
except subprocess.TimeoutExpired:
pass
I'm trying to integrate ESA'2 sen2cor python-script into my workflow. To do this I create a subprocess with which I call the "L2A_Process.bat" file, which in turn calls the "L2A_Process.py" script.
I want to launch the sen2cor-script with a timeout since it gets stuck and freezes from time to time, so as to automatically re-launch it if it failed.
To launch it and catch a timeout I successfully used the following script:
import os, subprocess
from signal import CTRL_BREAK_EVENT
timeout = 3600 #1hour
l1c_safe_path = "path/to/my/input/file.SAFE" #product that I want to process
command = ["L2A_process.bat", l1c_safe_path]
p = subprocess.Popen(command,shell=False, creationflags=subprocess.CREATE_NEW_PROCESS_GROUP)
try:
p.wait(timeout)
except subprocess.TimeoutExpired:
os.kill(p.pid, CTRL_BREAK_EVENT)
This is as far as I got. It results in the sen2cor-script being paused giving the following output:
Terminate batch job (Y/N)
I'd like to know how I can properly terminate my subprocess "p" with all it own child-subprocesses (i.e. "L2A_Process.py").
Some observations:
This script needs to run on Windows;
I've tried to kill the subprocess without the creationflag I've used in the example above: this results in the subprocess being killed but the "L2A_Process.py" script deteaches an keeps running (which is the core of my problem);
I cannot use a CTRL_C_EVENT since I want to re-launch the failed "L2A_Process.py" in a loop until it succeeds.
This code works for me to monitor Sen2cor status while converting L1C to L2A for Sentinel 2 data. The Sen2cor process is time and cpu consuming so be patient. It took half an hour to create L2A with DEM, DDV, etc. Hope it helps
from subprocess import Popen, PIPE
import os
pathtoprodS1C = "path_to_L1C_product" // safe file
outdirS2A = "output_dir" // where L2A files will be placed
pathtoL2Process = "path_to_L2A_Process" //if not in path
pathtoGIPP = "path_to_your_GIPP/L2A_GIPP.xml"
procName = "./L2A_Process"
os.chdir(pathtoL2Process)
import shlex
pcall = "./{} {} --output_dir {} --tif --GIP_L2A {}".format(procName,
pathtoprodS1C,
pathtoprodS2A,
pathtoGIPP)
args = shlex.split(pcall)
print(args)
try:
p = Popen(args, stdout=PIPE)
eut = p.stdout.readline()
while eut:
eut = p.stdout.readline()
print(eut)
finally:
print('Sen2Cor is Done')
exit()
I am new to Python.
I am trying to SSH to a server to perform some operations. However, before performing the operations, i need to load a profile, which takes 60-90 seconds. After loading the profile, is there a way to keep the SSH session open so that i can perform the operations later?
p = subprocess.Popen("ssh abc#xyz'./profile'", stdout=subprocess.PIPE, shell=True)
result = p.communicate()[0]
print result
return result
This loads the profile and exits. Is there a way to keep the above ssh session open and run some commands?
Example:
p = subprocess.Popen("ssh abc#xyz'./profile'", stdout=subprocess.PIPE, shell=True)
<More Python Code>
<More Python Code>
<More Python Code>
<Run some scripts/commands on xyz server non-interactively>
After loading the profile, I want to run some scripts/commands on the remote server, which I am able to do by simply doing below:
p = subprocess.Popen("ssh abc#xyz './profile;**<./a.py;etc>**'", stdout=subprocess.PIPE, shell=True)
However, once done, it exists and the next time I want to execute some script on the above server, I need to load the profile again (which takes 60-90 seconds). I am trying to figure out a way where we can create some sort of tunnel (or any other way) where the ssh connection remains open after loading the profile, so that the users don't have to wait 60-90 seconds whenever anything is to be executed.
I don't have access to strip down the profile.
Try an ssh library like asyncssh or spur. Keeping the connection object should keep the session open.
You could send a dummy command like date to prevent the timeout as well.
You have to construct a ssh command like this ['ssh', '-T', 'host_user_name#host_address'] then follow below code.
Code:
from subprocess import Popen, PIPE
ssh_conn = ['ssh', '-T', 'host_user_name#host_address']
# if you have to add port then ssh_conn should be as following
# ssh_conn = ['ssh', '-T', 'host_user_name#host_address', '-p', 'port']
commands = """
cd Documents/
ls -l
cat test.txt
"""
with Popen(ssh_conn, stdin=PIPE, stdout=PIPE, stderr=PIPE, universal_newlines=True) as p:
output, error = p.communicate(commands)
print(output)
print(error)
print(p.returncode)
# or can do following things
p.stdin.write('command_1')
# add as many command as you want
p.stdin.write('command_n')
Terminal Output:
Please let me know if you need further explanations.
N.B: You can add command in commands string as many as you want.
What you want to do is write/read to the process's stdin/stdout.
from subprocess import Popen, PIPE
import shlex
shell_command = "ssh user#address"
proc = Popen(shlex.split(shell_command), stdin=PIPE, universal_newlines=True)
# Do python stuff here
proc.stdin.write("cd Desktop\n")
proc.stdin.write("mkdir Example\n")
# And so on
proc.stdin.write("exit\n")
You must include the trailing newline for each command. If you prefer, print() (as of Python 3.x, where it is a function) takes a keyword argument file, which allows you to forget about that newline (and also gain all the benefits of print()).
print("rm Example", file=proc.stdin)
Additionally, if you need to see the output of your command, you can pass stdout=PIPE and then read via proc.stdout.read() (same for stderr).
You may also want to but the exit command in a try/finally block, to ensure you exit the ssh session gracefully.
Note that a) read is blocking, so if there's no output, it'll block forever and b) it will only return what was available to read from the stdout at that time- so you may need to read repeatedly, sleep for a short time, or poll for additional data. See the fnctl and select stdlib modules for changing blocking -> nonblocking read and polling for events, respectively.
Hello Koshur!
I think that what you are trying to achieve looks like what I've tried in the past when trying to make my terminal accessible from a private website:
I would open a bash instance, keep it open and would listen for commands through a WebSocket connection.
What I did to achieve this was using the O_NONBLOCK flag on STDOUT.
Example
import fcntl
import os
import shlex
import subprocess
current_process = subprocess.Popen(shlex.split("/bin/sh"), stdin=subprocess.PIPE,
stdout=subprocess.PIPE, stderr=subprocess.STDOUT) # Open a shell prompt
fcntl.fcntl(current_process.stdout.fileno(), fcntl.F_SETFL,
os.O_NONBLOCK) # Non blocking stdout and stderr reading
What I would have after this is a loop checking for new output in another thread:
from time import sleep
from threading import Thread
def check_output(process):
"""
Checks the output of stdout and stderr to send it to the WebSocket client
"""
while process.poll() is None: # while the process isn't exited
try:
output = process.stdout.read() # Read the stdout PIPE (which contains stdout and stderr)
except Exception:
output = None
if output:
print(output)
sleep(.1)
# from here, we are outside the loop: the process exited
print("Process exited with return code: {code}".format(code=process.returncode))
Thread(target=check_output, args=(current_process,), daemon=True).start() # Start checking for new text in stdout and stderr
So you would need to implement your logic to SSH when starting the process:
current_process = subprocess.Popen(shlex.split("ssh abc#xyz'./profile'"), stdin=subprocess.PIPE,
stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
And send commands like so:
def send_command(process, cmd):
process.stdin.write(str(cmd + "\n").encode("utf-8")) # Write the input to STDIN
process.stdin.flush() # Run the command
send_command(current_process, "echo Hello")
EDIT
I tried to see the minimum Python requirements for the given examples and found out that Thread(daemon) might not work on Python 2.7, which you asked in the tags.
If you are sure to exit the Thread before exiting, you can ignore daemon and use Thread() which works on 2.7. (You could for example use atexit and terminate the process)
References
fcntl(2) man page
https://man7.org/linux/man-pages/man2/fcntl.2.html
fcntl Python 3 Documentation
https://docs.python.org/3/library/fcntl.html
fcntl Python 2.7 Documentation
https://docs.python.org/2.7/library/fcntl.html
O_NONBLOCK Python 3 Documentation
https://docs.python.org/3/library/os.html#os.O_NONBLOCK
O_NONBLOCK Python 2.7 Documentation
https://docs.python.org/2.7/library/os.html#os.O_NONBLOCK
I have a script that I want to run from within Python (2.6.5) that follows the logic below:
Prompts the user for a password. It looks like ("Enter password: ") (*Note: Input does not echo to screen)
Output irrelevant information
Prompt the user for a response ("Blah Blah filename.txt blah blah (Y/N)?: ")
The last prompt line contains text which I need to parse (filename.txt). The response provided doesn't matter (the program could actually exit here without providing one, as long as I can parse the line).
My requirements are somewhat similar to Wrapping an interactive command line application in a Python script, but the responses there seem a bit confusing, and mine still hangs even when the OP mentions that it doesn't for him.
Through looking around, I've come to the conclusion that subprocess is the best way of doing this, but I'm having a few issues. Here is my Popen line:
p = subprocess.Popen("cmd", shell=True, stdout=subprocess.PIPE,
stderr=subprocess.STDOUT, stdin=subprocess.PIPE)
When I call a read() or readline() on stdout, the prompt is printer to the screen and it hangs.
If I call a write("password\n") for stdin, the prompt is written to the screen and it hangs. The text in write() is not written (I don't the cursor move the a new line).
If I call p.communicate("password\n"), same behavior as write()
I was looking for a few ideas here on the best way to input to stdin and possibly how to parse the last line in the output if your feeling generous, though I could probably figure that out eventually.
If you are communicating with a program that subprocess spawns, you should check out A non-blocking read on a subprocess.PIPE in Python. I had a similar problem with my application and found using queues to be the best way to do ongoing communication with a subprocess.
As for getting values from the user, you can always use the raw_input() builtin to get responses, and for passwords, try using the getpass module to get non-echoing passwords from your user. You can then parse those responses and write them to your subprocess' stdin.
I ended up doing something akin to the following:
import sys
import subprocess
from threading import Thread
try:
from Queue import Queue, Empty
except ImportError:
from queue import Queue, Empty # Python 3.x
def enqueue_output(out, queue):
for line in iter(out.readline, b''):
queue.put(line)
out.close()
def getOutput(outQueue):
outStr = ''
try:
while True: # Adds output from the Queue until it is empty
outStr+=outQueue.get_nowait()
except Empty:
return outStr
p = subprocess.Popen("cmd", stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False, universal_newlines=True)
outQueue = Queue()
errQueue = Queue()
outThread = Thread(target=enqueue_output, args=(p.stdout, outQueue))
errThread = Thread(target=enqueue_output, args=(p.stderr, errQueue))
outThread.daemon = True
errThread.daemon = True
outThread.start()
errThread.start()
try:
someInput = raw_input("Input: ")
except NameError:
someInput = input("Input: ")
p.stdin.write(someInput)
errors = getOutput(errQueue)
output = getOutput(outQueue)
Once you have the queues made and the threads started, you can loop through getting input from the user, getting errors and output from the process, and processing and displaying them to the user.
Using threading it might be slightly overkill for simple tasks.
Instead os.spawnvpe can be used. It will spawn script shell as a process. You will be able to communicate interactively with the script.
In this example I passed password as an argument, obviously that is not a good idea.
import os
import sys
from getpass import unix_getpass
def cmd(cmd):
cmd = cmd.split()
code = os.spawnvpe(os.P_WAIT, cmd[0], cmd, os.environ)
if code == 127:
sys.stderr.write('{0}: command not found\n'.format(cmd[0]))
return code
password = unix_getpass('Password: ')
cmd_run = './run.sh --password {0}'.format(password)
cmd(cmd_run)
pattern = raw_input('Pattern: ')
lines = []
with open('filename.txt', 'r') as fd:
for line in fd:
if pattern in line:
lines.append(line)
# manipulate lines
If you just want a user to enter a password without it being echoed to the screen just use the standard library's getpass module:
import getpass
print("You entered:", getpass.getpass())
NOTE:The prompt for this function defaults to "Password: " also this will only work on command lines where echoing can be controlled. So if it doesn't work try running it from terminal.
I am trying to run a .bat file (which acts as a simulator) in a new window, so it must always be running in the background. I think that creating a new process is the only option that I have. Basically, I want my code to do something like this:
def startSim:
# open .bat file in a new window
os.system("startsim.bat")
# continue doing other stuff here
print("Simulator started")
I'm on Windows so I can't do os.fork.
Use subprocess.Popen (not tested on Windows, but should work).
import subprocess
def startSim():
child_process = subprocess.Popen("startsim.bat")
# Do your stuff here.
# You can terminate the child process after done.
child_process.terminate()
# You may want to give it some time to terminate before killing it.
time.sleep(1)
if child_process.returncode is None:
# It has not terminated. Kill it.
child_process.kill()
Edit: you could also use os.startfile (Windows only, not tested too).
import os
def startSim():
os.startfile("startsim.bat")
# Do your stuff here.
Looks like you want "os.spawn*", which seems to equate to os.fork, but for Windows.
Some searching turned up this example:
# File: os-spawn-example-3.py
import os
import string
if os.name in ("nt", "dos"):
exefile = ".exe"
else:
exefile = ""
def spawn(program, *args):
try:
# check if the os module provides a shortcut
return os.spawnvp(program, (program,) + args)
except AttributeError:
pass
try:
spawnv = os.spawnv
except AttributeError:
# assume it's unix
pid = os.fork()
if not pid:
os.execvp(program, (program,) + args)
return os.wait()[0]
else:
# got spawnv but no spawnp: go look for an executable
for path in string.split(os.environ["PATH"], os.pathsep):
file = os.path.join(path, program) + exefile
try:
return spawnv(os.P_WAIT, file, (file,) + args)
except os.error:
pass
raise IOError, "cannot find executable"
#
# try it out!
spawn("python", "hello.py")
print "goodbye"
On Windows, a background process is called a "service". Check this other question about how to create a Windows service with Python: Creating a python win32 service
import subprocess
proc = subprocess.Popen(['/path/script.bat'],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
Using subprocess.Popen() will run the given .bat path ( or any other executable).
If you do wish to wait for the process to finish just add proc.wait():
proc.wait()