Python子流程更新子流程

Question

Is it possible to update portions of a subprocess spawned via Popen([cmd], stdin=PIPE) ?

I've been trying to build a script that interacts with a GUI for updating files. Here is what I've been toying with:

def __init__(self):
    #... <SNIPPED>
    process = self.outer._display(self.custom['dialog_name'], _passed, return_process=True)
    # Returns executed list, example -> ['/bin/foo', '--bar', '0', '--lyn', 'twenty']
    self.pipe = subprocess.Popen(process, stdin=subprocess.PIPE)

The pipe is built in the __init__ of my class. I want to be able to run the following function to update the process.

def update(self, bar, lyn):
    self.pipe.communicate('--bar {} --lyn {}\n'.format(bin, lyn))

After running the update function after initializing the class containing the pipe , the subprocess is not updated. I'm pretty new to Python, so I wouldn't be surprised if I was approaching this the wrong way.

If you can either help explain what I'm doing wrong or a better solution to this issue, please let me know.

Answer 1

I've been able to achieve what I want via os.popen, but I rather use the preferred (subprocess)

Each os.popen() starts a new shell process. self.pipe.communicate() doesn't start a new process: it writes all input, reads all output, and waits for the process to finish.

To start a command with a new set of parameters:

def update(self, bar, lyn):
    cmd = ['/bin/foo', '--bar', bar, '--lyn', lyn]
    self.processes.append(subprocess.Popen(cmd))