Submitting a complex cmd string made of a full file path to an executable, the multiple flags, arguments, parameters, inputs and outputs seems to require me to set shell=True otherwise subprocess.Popen is not able understand anything more complex than just a simple path to executable (with no spaces in a filepath).
In my example I have quite a long cmd:
cmd = " '/Application/MyApp.app/Contents/MacOS/my_executable' '/Path/to/input/files' -some -flags -here -could -be -a -lot '/full/path/to/output/files' "
Submitting this cmd to subprocess.Popen " results to an error that complains on something about the path and not being able to find it.
So instead of using :
proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
check_call seems workings quite well:
proc = subprocess.check_call(cmd, shell=True)
Interesting, only after shell is set to True
shell=True
the subprocess.check_call works with a supplied cmd.
The side effect is that the rest of the code seems proceeds running without waiting for subprocess.check_call(cmd, shell=True) to finish first.
The code is designed the way that the rest of the execution is dependent on a result of subprocess.check_call(cmd, shell=True).
I wonder if there is anyway to enforce the code execution to wait till subprocess.check_call(cmd, shell=True) is finished. Thanks in advance!
As @mikkas suggest just use it as a list here is a working example:
mainProcess = subprocess.Popen(['python', pyfile, param1, param2], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
# get the return value from the method
communicateRes = mainProcess.communicate()
stdOutValue, stdErrValue = communicateRes
You are calling python.exe pyfile param1 param2
By using communicate() you can get the stdout and stderr as a Tuple
You can use python method split() to split your string to a list for example:
cmd = "python.exe myfile.py arg1 arg2"
cmd.split(" ")
Output:
['python.exe', 'myfile.py', 'arg1', 'arg2']