subprocess not working after onefile pyinstaller even with stdout/stdin defined

[Matthew Lawrence]

Hi - I posted this question to Stack Overflow (https://stackoverflow.com/questions/68042440/subprocess-not-working-after-onefile-pyinstaller-even-with-stdout-stdin-defined), but haven't had a response, so thought I'd try here.  Apologies if this is not the right forum.

I have a tkinter GUI with a text box and run button. Pressing the run button turns it to yellow and starts a subroutine that prints a few numbers. Text output from the subroutine is redirected to the GUI text box. However, after creating a standalone executable file with pyinstaller, it no longer works. Pressing the run button doesn't seem to start the subprocess. It does turn yellow, but no text appears in the text box and it seems to start another instance of the main program - a second GUI appears after about 10 seconds which is how long it takes for the initial GUI to appear. The run button stays yellow on the initial GUI.

I've seen a bit online about other people having issues with subprocesses not running after pyinstaller, but most of the solutions seem to be to make sure stdout, stdin are set to subprocess.PIPE which I have, so I'm at a bit of a loss what to try next.

When running the resulting executable from Anaconda prompt, I also get no error messages or anything useful to help debug.

I'm creating my standalone with this:

pyinstaller --onefile --add-data "testsubprocess.py;." simpleGUI.py

I've also tried without  --add-data "testsubprocess.py;.", making sure my executable and testsubprocess.py are in the same folder.

My subprocess file, testsubprocess.py is:

import time

for i in range(3):

    print("%d.%d" % divmod(i, 10))

    time.sleep(0.5)

My main GUI file, simpleGUI.py, is:

import sys

import subprocess

from threading import Thread

import tkinter as tk

from queue import Queue, Empty

def iter_except(function, exception):

    try:

        while True:

            yield function()

    except exception:

        return

class DisplaySubprocessOutputDemo:

    def __init__(self, root):

        self.root = root

        width=600

        height=350

        xloc=0

        yloc=10

        self.root.geometry('%dx%d+%d+%d' % (width, height, xloc, yloc))

        self.statustext = tk.Text(self.root, height=4, width=30)

        self.statustext.grid(row=3, column=1)

        self.startbutton = tk.Button(self.root, text = 'Start', command=self.startprocess, bg='green', activebackground = 'orange')

        self.startbutton.config(height = 2, width = 15)

        self.startbutton.grid(row = 5, column=0,sticky='E')

        self.startbuttonpresses = 0

        

        exitbutton = tk.Button(self.root, text = 'Exit', command=self.quit, bg='red')

        exitbutton.config(height = 2, width = 15)

        exitbutton.grid(row = 5, column=4, sticky='E')

        

        

    def startprocess(self):    

        self.startbuttonpresses = self.startbuttonpresses+1

        

        if self.startbuttonpresses == 1:

            

            self.startbutton.configure(bg='yellow')

            self.startbutton.configure(text='Stop')

         

            self.process = subprocess.Popen([sys.executable, "-u", "testsubprocess.py"], shell=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.STDOUT)

    

            q = Queue(maxsize=1024)  

            t = Thread(target=self.reader_thread, args=[q])

            t.daemon = True 

            t.start()

    

            self.updatetext(q) 

            

        else:

            self.startbuttonpresses = 0

            self.process.kill()

            self.startbutton.configure(bg='green')

            self.startbutton.configure(text='Start')

            

    def reader_thread(self, q):

        try:

            with self.process.stdout as pipe:

                for line in iter(pipe.readline, b''):

                    q.put(line)

        finally:

            q.put(None)

    def updatetext(self, q):

        for line in iter_except(q.get_nowait, Empty): # display all content

            if line is None:

                self.startbuttonpresses = 0

                self.startbutton.configure(bg='green')

                self.startbutton.configure(text='Start')

                

                return

            else:

                self.statustext.insert(tk.END, line)

        self.root.after(400, self.updatetext, q) 

    def quit(self):

        try:

            self.process.kill() 

        except Exception:

            pass

        self.root.destroy()

root = tk.Tk()

app = DisplaySubprocessOutputDemo(root)

root.protocol("WM_DELETE_WINDOW", app.quit)

root.eval('tk::PlaceWindow %s center' % root.winfo_pathname(root.winfo_id()))

root.mainloop()

[Steve Barnes]

A couple of things occur to me on looking at your code:

 

1. You have not if __name__ == "__main__": in your file - this is a great pattern to follow.
2. You would probably be better off using the multiprocessing library rather than subprocess

When you code: self.process = subprocess.Popen([sys.executable, "-u", "testsubprocess.py"], shell=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.STDOUT) is executed directly as python simpleGUI.py then sys.executable will be /path/to/python.exe but when you execute your simpleGUI.exe then it will be simpleGUI.exe this is why you get a new instance!

 

Hope that helps!

 

Steve

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[bwoodsend]

subprocess.Popen([sys.executable, “-u”, “testsubprocess.py”],

A frozen application does not ship a Python interpreter. Instead sys.executable points to your EXE file which is equivalent to python testsubprocess.py so what you’re effectively running is subprocess.Popen(["python", "testsubprocess.py", "-u", "testsubprocess.py"], which will result in an infinite loop of subprocesses with every process invoking another child process. As Steve says, use the multiprocessing module and make sure you use the freeze_support() function.

And for the reference, the issue with having to assign all 3 stdin, stdout, stderr is only applicable to --windowed mode and simply results in an exception of you don’t do it.

​

[Matthew Lawrence]

Thank you - that is helpful.

I'm sure it's not recommended, but I can get everything to work now if I replace sys.executable in the code with the path to my python.exe in quotes.

Matthew

[Steve Barnes]

Hi Matthew,

 

That will work on your machine at least as long as you don't change where python is installed but not on the machine of anybody else who doesn't have python installed in exactly the same place - since you are using pyinstaller I would guess that this is not what you would want.

To view this discussion on the web visit https://groups.google.com/d/msgid/pyinstaller/77c2276a-8850-406e-bc7d-75dfdbf75ed6n%40googlegroups.com.