How to print messages in tkinter from subprocess?

Question

everyone! I've run into a problem. Let's say I have a script that is launched using subprocess module from tkinter giu like this (params includes the name of the script):

p = Popen(['python.exe'] + params)

During being executed, my script has some messages that I want to be printed in my gui. While I was using console, I just did it with print function like this:

print(f'Connected to {ppm_file}')

What I now need to do, is to make this message be printed in a text widget in tkinter gui.

I suppose it implys using stdout, but I'm a newbie to this concept and find it a little bit hard to understand.

Thanks for your help!

Answer 1

You can capture the console output of the external script and insert the captured output into a Text widget.

Below is an example:

import tkinter as tk
import subprocess
import threading

root = tk.Tk()

logbox = tk.Text(root, width=80, height=20)
logbox.pack()

def capture_output():
    # "python -u" make stdout stream to be unbuffered
    p = subprocess.Popen(["python", "-u", "other.py"], stdout=subprocess.PIPE)
    while p.poll() is None: # process is still running
        logbox.insert("end", p.stdout.readline())
        logbox.see("end")
    logbox.insert("end", "--- done ---\n")

# use thread so that it won't block the application
tk.Button(root, text="Run", command=lambda: threading.Thread(target=capture_output, daemon=True).start()).pack()

root.mainloop()