caylon/main.py

import pathlib
import subprocess
import asyncio
import os

HOME_DIR = str(pathlib.Path(os.getcwd()).parent.parent.resolve())
PARENT_DIR = str(pathlib.Path(__file__).parent.resolve())

class Plugin:
    backend_proc = None
    # Asyncio-compatible long-running code, executed in a task when the plugin is loaded
    async def _main(self):
        # startup
        self.backend_proc = subprocess.Popen(
            [PARENT_DIR + "/bin/backend", "--config", "./caylon.json"],
            env = dict(os.environ))
        while True:
            await asyncio.sleep(1)

    async def _unload(self):
        # shutdown
        if self.backend_proc is not None:
            self.backend_proc.terminate()
            try:
                self.backend_proc.wait(timeout=5) # 5 seconds timeout
            except subprocess.TimeoutExpired:
                self.backend_proc.kill()
            self.backend_proc = None