Threading

__init__.py

import bpy
import subprocess
import threading
import re


# Function to parse progress from subprocess output
def parse_progress(line):
    """
    Parses progress information from a line of output.
    Example format: '23/100 [===>   ] 23%' or similar.
    Adjust regex as needed for your specific progress format.
    """
    match = re.search(r"(\d+)/(\d+)", line)
    if match:
        current = int(match.group(1))
        total = int(match.group(2))
        progress = current / total
        return progress
    return None


# Function to handle subprocess output
def process_output(stdout, stderr):
    """
    Reads the subprocess output and updates Blender's system bar progress.
    """
    wm = bpy.context.window_manager
    wm.progress_begin(0, 1)  # Start progress (min=0, max=1)

    try:
        for line in iter(stdout.readline, b""):
            line = line.decode().strip()
            print(line)  # Print to Blender's console for debugging

            # Try to parse progress from the line
            progress = parse_progress(line)
            if progress is not None:
                wm.progress_update(progress)  # Update Blender progress bar

        # Process stderr if needed
        if stderr:
            for line in iter(stderr.readline, b""):
                print("Error:", line.decode().strip())
    finally:
        wm.progress_end()  # End progress


# Function to run any subprocess command in a thread
def run_subprocess_in_thread(command, **kwargs):
    """
    Run a subprocess command in a separate thread.

    Args:
        command (list or str): The command to run (list for arguments).
        **kwargs: Additional keyword arguments to pass to subprocess.Popen.
    """
    def task():
        # Run the subprocess
        try:
            process = subprocess.Popen(
                command,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,  # Ensure text output (Python 3.6+)
                **kwargs,
            )
            process_output(process.stdout, process.stderr)
        except Exception as e:
            print(f"Subprocess Error: {e}")

    # Run the task in a separate thread
    thread = threading.Thread(target=task)
    thread.start()


# Add a button in the UI to trigger the subprocess
class RunSubprocessOperator(bpy.types.Operator):
    """Run Subprocess Example"""
    bl_idname = "wm.run_subprocess_example"
    bl_label = "Run Subprocess Example"

    def execute(self, context):
        # Replace with your actual subprocess command
        # Example: Simulating progress (Linux/macOS: 'seq', Windows: 'for /L')
        # This command simulates a progress bar-like output
        run_subprocess_in_thread(["python", "-c", """
import time
for i in range(1, 24):
    print(f'{i}/23 [{"="*i:<23}] {i*100//23}%')
    time.sleep(0.5)
        """])
        return {'FINISHED'}


# Register the operator and add to the UI
def menu_func(self, context):
    self.layout.operator(RunSubprocessOperator.bl_idname)


def register():
    bpy.utils.register_class(RunSubprocessOperator)
    bpy.types.TOPBAR_MT_file.append(menu_func)


def unregister():
    bpy.utils.unregister_class(RunSubprocessOperator)
    bpy.types.TOPBAR_MT_file.remove(menu_func)


# Enable the script to run in Blender
if __name__ == "__main__":
    register()