switch from WSGI using uWSGI to ASGI using custom event loop based on uvicorn

core/server.py

@@ -0,0 +1,130 @@
+#!/usr/bin/env python3
+import asyncio
+import logging
+
+import uvicorn
+from aiosmtpd.controller import Controller, UnixSocketController
+from aiosmtpd.lmtp import LMTP
+
+
+async def handle_echo(reader, writer):
+    # session = Session()
+    data = await reader.read(100)
+    message = data.decode()
+    addr = writer.get_extra_info('peername')
+
+    print(f"Received {message!r} from {addr!r}")
+
+    print(f"Send: {message!r}")
+    writer.write(data)
+    await writer.drain()
+
+    print("Close the connection")
+    writer.close()
+    await writer.wait_closed()
+
+
+class ExampleHandler:
+    async def handle_RCPT(self, server, session, envelope, address, rcpt_options):
+        if not address.endswith('@example.com'):
+            return '550 not relaying to that domain'
+        envelope.rcpt_tos.append(address)
+        return '250 OK'
+
+    async def handle_DATA(self, server, session, envelope):
+        print('Message from %s' % envelope.mail_from)
+        print('Message for %s' % envelope.rcpt_tos)
+        print('Message data:\n')
+        for ln in envelope.content.decode('utf8', errors='replace').splitlines():
+            print(f'> {ln}'.strip())
+        print()
+        print('End of message')
+        return '250 Message accepted for delivery'
+
+
+class LTMPController(Controller):
+    def factory(self):
+        return LMTP(self.handler)
+
+
+class UnixSocketLMTPController(UnixSocketController):
+    def factory(self):
+        return LMTP(self.handler)
+
+
+class UvicornServer(uvicorn.Server):
+    def install_signal_handlers(self):
+        pass
+
+
+async def web():
+    log_config = uvicorn.config.LOGGING_CONFIG
+    log_config["handlers"]["default"] = {"class": "logging.FileHandler", "filename": "web.log", "formatter": "default"}
+    log_config["handlers"]["access"] = {"class": "logging.FileHandler", "filename": "web-access.log",
+                                        "formatter": "access"}
+    config = uvicorn.Config("core.asgi:application", uds="web.sock", log_config=log_config)
+    server = UvicornServer(config=config)
+    await server.serve()
+
+
+async def tcp():
+    log = logging.getLogger('test')
+    log.info("Starting TCP server")
+    server = await asyncio.start_unix_server(handle_echo, path='test.sock')
+
+    addrs = ', '.join(str(sock.getsockname()) for sock in server.sockets)
+    log.info(f'Serving on {addrs}')
+
+    async with server:
+        await server.serve_forever()
+    log.info("TCP done")
+
+
+async def lmtp():
+    log = logging.getLogger('lmtp')
+    log.info("Starting LMTP server")
+    cont = UnixSocketLMTPController(ExampleHandler(), unix_socket='lmtp.sock')
+    cont.start()
+    log.info("LMTP done")
+
+
+async def shutdown(sig, loop):
+    log = logging.getLogger()
+    log.info(f"Received exit signal {sig.name}...")
+    tasks = [t for t in asyncio.all_tasks() if t is not
+             asyncio.current_task()]
+    [task.cancel() for task in tasks]
+    log.info(f"Cancelling {len(tasks)} outstanding tasks")
+    await asyncio.wait_for(loop.shutdown_asyncgens(), timeout=10)
+    loop.stop()
+    log.info("Shutdown complete.")
+
+
+def main():
+    import sdnotify
+    import signal
+    import setproctitle
+    setproctitle.setproctitle("c3lf-sys3")
+    logging.basicConfig(filename='server.log', level=logging.DEBUG, encoding='utf-8')
+    logging.basicConfig(filename='test.log', level=logging.DEBUG, encoding='utf-8')
+    logging.basicConfig(filename='lmtp.log', level=logging.DEBUG, encoding='utf-8')
+    log = logging.getLogger()
+    log.info("Starting server")
+    loop = asyncio.get_event_loop()
+    loop.add_signal_handler(signal.SIGTERM, lambda: asyncio.create_task(shutdown(signal.SIGTERM, loop)))
+    loop.add_signal_handler(signal.SIGINT, lambda: asyncio.create_task(shutdown(signal.SIGINT, loop)))
+    loop.create_task(web())
+    loop.create_task(tcp())
+    loop.create_task(lmtp())
+    n = sdnotify.SystemdNotifier()
+    n.notify("READY=1")
+    log.info("Server ready")
+    try:
+        loop.run_forever()
+    finally:
+        loop.close()
+    logging.info("Server stopped")
+
+
+if __name__ == '__main__':
+    main()