"""Listening sockets across a reload: a service of the new configuration on the same address and port takes over the old service's socket, so clients connecting all the while are never refused nor reset.""" import socket import threading import time def run(t): origin = t.free_port() proxy = t.free_port() adm = t.free_port() conf = f""" log auth iponly allow * http data * /data httpsrv -p{origin} flush auth iponly allow * proxy -p{proxy} admin -p{adm} """ server = t.start("takeover", conf, ports=[origin, proxy, adm]) done = {"ok": 0, "failed": 0, "errors": []} stop = threading.Event() def client(): url = f"http://127.0.0.1:{origin}/data?size=2000" while not stop.is_set(): r = t.http(url, proxy=f"127.0.0.1:{proxy}") if r.status == 200 and r.length == 2000: done["ok"] += 1 else: done["failed"] += 1 if len(done["errors"]) < 3: done["errors"].append(r.error or r.status) # paced, so as not to run out of local ports time.sleep(0.02) clients = [threading.Thread(target=client) for _ in range(4)] for c in clients: c.start() for i in range(3): time.sleep(0.5) before = server.output().count("taken over") t.write_config("takeover", conf) t.http(f"http://127.0.0.1:{adm}/R") deadline = time.time() + 10 while time.time() < deadline and server.output().count("taken over") < before + 3: time.sleep(0.05) # the old services stop within a second of each reload time.sleep(1.5) stop.set() for c in clients: c.join(20) taken = server.output().count("Accepting connections, taken over") t.eq(9, taken, "each reload hands the three listening sockets over") t.ok(f"requests go on through the reloads ({done['ok']})") if done["ok"] > 100 else \ t.fail("requests go on through the reloads", "more than 100", done["ok"]) t.eq(0, done["failed"], "no request is refused or reset by a reload " f"(first errors: {done['errors']})") # --- UDP: the socket is handed over too, and a session of the old # service goes on through it, its datagrams forwarded by the new one --- echo = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) echo.bind(("127.0.0.1", 0)) echo_port = echo.getsockname()[1] def echo_server(): while True: try: data, addr = echo.recvfrom(2048) except OSError: return echo.sendto(data, addr) threading.Thread(target=echo_server, daemon=True).start() udp = t.free_port() uconf = conf + f"\n udppm {udp} 127.0.0.1 {echo_port}\n" t.write_config("takeover", uconf) t.http(f"http://127.0.0.1:{adm}/R") time.sleep(1.5) client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) client.settimeout(1) sent = lost = 0 stopudp = time.time() + 5 reloads = 0 next_reload = time.time() + 0.5 while time.time() < stopudp: if reloads < 3 and time.time() >= next_reload: t.write_config("takeover", uconf) t.http(f"http://127.0.0.1:{adm}/R") reloads += 1 next_reload = time.time() + 1.2 msg = f"n{sent}".encode() client.sendto(msg, ("127.0.0.1", udp)) sent += 1 try: data, _ = client.recvfrom(2048) if data != msg: lost += 1 except OSError: lost += 1 time.sleep(0.02) client.close() echo.close() t.ok(f"a UDP session sends through three reloads ({sent} datagrams)") if sent > 100 else \ t.fail("a UDP session sends through three reloads", "more than 100", sent) t.eq(0, lost, "and every datagram comes back, the socket handed over") t.contains(server.output(), f"{udp} 0.0.0.0:0 0 0 0 Accepting connections, taken over", "the UDP service takes the socket over") # --- options: a live -ol option changed is set on the socket taken over, # a bind-time one makes another socket; two services of one # configuration on one address are each taken over ---------------------- def taken_for(port, since): return server.output()[since:].count(f":{port} 0.0.0.0:0 0 0 0 Accepting connections, taken over") def reload_conf(c): mark = len(server.output()) t.write_config("takeover", c) t.http(f"http://127.0.0.1:{adm}/R") time.sleep(1.5) return mark oconf = conf.replace(f"proxy -p{proxy}", f"proxy -olTCP_NODELAY -p{proxy}") reload_conf(oconf) mark = reload_conf(oconf.replace("-olTCP_NODELAY", "-olTCP_NODELAY,SO_KEEPALIVE")) t.eq(1, taken_for(proxy, mark), "a live socket option changed: the socket is taken over") t.eq(200, t.http(f"http://127.0.0.1:{origin}/data?size=100", proxy=f"127.0.0.1:{proxy}").status, "and serves") mark = reload_conf(oconf.replace("-olTCP_NODELAY", "-olTCP_NODELAY,SO_KEEPALIVE,SO_REUSEADDR=0")) t.eq(0, taken_for(proxy, mark), "a bind-time socket option changed: another socket") t.ok("which serves") if t.wait_port(proxy) and t.http( f"http://127.0.0.1:{origin}/data?size=100", proxy=f"127.0.0.1:{proxy}").status == 200 else \ t.fail("which serves", 200, "no answer") twice = conf.replace(f"proxy -p{proxy}", f"proxy -p{proxy}\n proxy -p{proxy}") reload_conf(twice) mark = reload_conf(twice) t.eq(2, taken_for(proxy, mark), "two services on one address are both taken over") reload_conf(conf) # a changed port is a new socket: the old one closes, the new one opens moved = t.free_port() t.write_config("takeover", conf.replace(f"proxy -p{proxy}", f"proxy -p{moved}")) t.http(f"http://127.0.0.1:{adm}/R") t.ok("a service moved to another port listens there") if t.wait_port(moved) else \ t.fail("a service moved to another port listens there", "open", "closed") deadline = time.time() + 5 while time.time() < deadline and t.wait_port(proxy, timeout=0.2): time.sleep(0.2) with socket.socket() as s: s.settimeout(1) refused = s.connect_ex(("127.0.0.1", proxy)) != 0 t.ok("and its old port is closed") if refused else \ t.fail("and its old port is closed", "refused", "accepted")