Slow

slow.py

from time import time
from functools import partial
import random
import trio  # python3 -m pip install --upgrade trio

FTP_RESPONSE = "\r\n".join([
    "220 ProFTPD 1.3.1 Server (ProFTPD)",
    "220 " + "".join(random.choice('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ') for _ in range(1001)),
    "331 Password required"
])
HTTP_RESPONSE = "\r\n".join([
    "HTTP/1.1 200 OK",
    "connection: close",
    "server: gws",
    "content-type: text/html",
    "content-length: 2001"
    "", "",
    "".join(random.choice('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ') for _ in range(2001))
])

def e(extra):
    return extra + random.random()

t0 = time()
def log(msg):
    print(f"[{int(time()-t0)}] {msg}")

async def slow_read(stream):
    while b"" != await stream.receive_some(max_bytes=1):
        await trio.sleep(e(0.2))

async def slow_write(content, stream):
    for c in content:
        await trio.sleep(e(0.2))
        await stream.send_all(c.encode())

async def handler(content, stream):
    log(f"Got conn: {stream.socket}")
    async with trio.open_nursery() as nursery:
        nursery.start_soon(slow_read, stream)
        await trio.sleep(e(0.1))
        nursery.start_soon(partial(slow_write, content), stream)
    log(f"End conn: {stream}")

async def run_on_port(content, port):
    while True:
        try:
            f = partial(handler, content)
            await trio.serve_tcp(f, port)
        except Exception as ex:
            log(f"Server dead on port {port}. Exception: {ex}")

async def main():
    async with trio.open_nursery() as nursery:
        nursery.start_soon(run_on_port, FTP_RESPONSE, 21)
        nursery.start_soon(run_on_port, HTTP_RESPONSE, 80)
        nursery.start_soon(run_on_port, HTTP_RESPONSE, 81)
        nursery.start_soon(run_on_port, HTTP_RESPONSE, 8080)

if __name__ == '__main__':
    trio.run(main)