Capture output from terminal (external program)

[3rav]

I have a simple program to run an external program (ccx.exe and cgx.exe, CalculiX solver and prepost), how can I capture their output from the terminal and display it live in a window (trame)?

# -----------------------------------------------------------------------------
# Run CGX
# -----------------------------------------------------------------------------
def run_cgx():
    if not os.path.isfile(CGX_PATH):
        state.output = f"ERROR: cgx not found:\n{CGX_PATH}\n"
        state.dirty("output")
        return

    if not os.path.isfile(FBD_PATH):
        state.output = f"ERROR: cgx.fbd not found:\n{FBD_PATH}\n"
        state.dirty("output")
        return

    state.output += "\nRunning CGX...\n"
    state.dirty("output")

    def worker():
        try:
            p = subprocess.Popen(
                [CGX_PATH, "-b", FBD_PATH],
                cwd=FBD_DIR,
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,
                text=True,
            )

            for line in p.stdout:
                state.output += line
                state.dirty("output")

            state.output += f"\n--- CGX finished ({p.returncode}) ---\n"
            state.dirty("output")

        except Exception as e:
            state.output += f"\nERROR: {e}\n"
            state.dirty("output")

    threading.Thread(target=worker, daemon=True).start()

ctrl.run_cgx = run_cgx

The script works in such a way that at the start it displays the information "Running CGX..." but it does not display the live output from cgx, after clicking the start button again only then it updates and you can see the previous output of the cgx process.

[jourdain]

def run_cgx():
    if not os.path.isfile(CGX_PATH):
        state.output = f"ERROR: cgx not found:\n{CGX_PATH}\n"
        return

    if not os.path.isfile(FBD_PATH):
        state.output = f"ERROR: cgx.fbd not found:\n{FBD_PATH}\n"
        return

    state.output += "\nRunning CGX...\n"

    def worker():
        try:
            p = subprocess.Popen(
                [CGX_PATH, "-b", FBD_PATH],
                cwd=FBD_DIR,
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,
                text=True,
            )

            for line in p.stdout:
                with state:
                   state.output += line

            with state:
               state.output += f"\n--- CGX finished ({p.returncode}) ---\n"


        except Exception as e:
            with state:
               state.output += f"\nERROR: {e}\n"

    threading.Thread(target=worker, daemon=True).start()

ctrl.run_cgx = run_cgx