TCP echo server implemented using asyncio

echo.py

#!/usr/bin/env python3
"""TCP echo server

Implemented using asyncio for concurrent client handling

"""
import asyncio
import argparse
import logging


class EchoServer:

	address = "localhost"
	port = 8888

	_server = None

	def __init__(self, address=None, port=None):
		logging.basicConfig(
			level=logging.INFO,
			format="[%(asctime)s] %(levelname)s: %(message)s"
		)
		if address is not None:
			self.address = address
		if port is not None:
			self.port = port

	async def _init_server(self):
		"""Instantiate server"""
		self._server = await asyncio.start_server(
			self._echo,
			host=self.address,
			port=self.port,
			start_serving=False
		)

	async def _echo(self, reader, writer):
		"""Echo connection data"""
		client = writer.get_extra_info("peername")
		logging.info(f"{client}: Connected")
		data = await reader.readline()
		while data:
			logging.info(f"{client}: Received: {data}")
			await asyncio.sleep(1)   # Simulate e.g. network latency
			writer.write(data)
			await writer.drain()
			logging.info(f"{client}: Sent: {data}")
			data = await reader.readline()
		writer.write_eof()
		writer.close()
		await writer.wait_closed()
		logging.info(f"{client}: Disconnected")

	async def _listen(self):
		"""Start listening"""
		async with self._server:
			logging.info("Echo server started")
			logging.info(f"Listening on {self.address}:{self.port}")
			await self._server.serve_forever()

	async def __call__(self):
		"""Async main"""
		await self._init_server()
		await self._listen()

	def up(self):
		"""Start server"""
		try:
			asyncio.run(self())
		except KeyboardInterrupt:
			logging.info("Stopping echo server")


if __name__ == "__main__":
	parser = argparse.ArgumentParser(
		description="A simple TCP echo server"
	)
	parser.add_argument(
		"-a", "--address",
		nargs="?",
		default=EchoServer.address,
		help="Server address"
	)
	parser.add_argument(
		"-p", "--port",
		nargs="?",
		type=int,
		default=EchoServer.port,
		help="Port to listen on"
	)
	args = parser.parse_args()
	EchoServer(address=args.address, port=args.port).up()