Merge branch '2216-find-servers-concurrently' into 2216-fix-connection-issues

monkey/infection_monkey/network/relay/utils.py

@@ -1,20 +1,53 @@
 import logging
 import socket
+from contextlib import suppress
 from ipaddress import IPv4Address
-from typing import Iterable, Optional
+from typing import Dict, Iterable, Iterator, MutableMapping, Optional
 
 import requests
 
 from common.common_consts.timeouts import MEDIUM_REQUEST_TIMEOUT
 from common.network.network_utils import address_to_ip_port
 from infection_monkey.network.relay import RELAY_CONTROL_MESSAGE_REMOVE_FROM_WAITLIST
-from infection_monkey.utils.threading import create_daemon_thread
+from infection_monkey.utils.threading import (
+    ThreadSafeIterator,
+    create_daemon_thread,
+    run_worker_threads,
+)
 
 logger = logging.getLogger(__name__)
 
+# The number of Island servers to test simultaneously. 32 threads seems large enough for all
+# practical purposes. Revisit this if it's not.
+NUM_FIND_SERVER_WORKERS = 32
+
 
 def find_server(servers: Iterable[str]) -> Optional[str]:
-    for server in servers:
+    server_list = list(servers)
+    server_iterator = ThreadSafeIterator(server_list.__iter__())
+    server_results: Dict[str, bool] = {}
+
+    run_worker_threads(
+        _find_island_server,
+        "FindIslandServer",
+        args=(server_iterator, server_results),
+        num_workers=NUM_FIND_SERVER_WORKERS,
+    )
+
+    for server in server_list:
+        if server_results[server]:
+            return server
+
+    return None
+
+
+def _find_island_server(servers: Iterator[str], server_status: MutableMapping[str, bool]):
+    with suppress(StopIteration):
+        server = next(servers)
+        server_status[server] = _check_if_island_server(server)
+
+
+def _check_if_island_server(server: str) -> bool:
     logger.debug(f"Trying to connect to server: {server}")
 
     try:
@@ -24,7 +57,7 @@ def find_server(servers: Iterable[str]) -> Optional[str]:
             timeout=MEDIUM_REQUEST_TIMEOUT,
         )
 
-            return server
+        return True
     except requests.exceptions.ConnectionError as err:
         logger.error(f"Unable to connect to server/relay {server}: {err}")
     except TimeoutError as err:
@@ -34,7 +67,7 @@ def find_server(servers: Iterable[str]) -> Optional[str]:
             f"Exception encountered when trying to connect to server/relay {server}: {err}"
         )
 
-    return None
+    return False
 
 
 def send_remove_from_waitlist_control_message_to_relays(servers: Iterable[str]):

monkey/infection_monkey/utils/threading.py

@@ -1,8 +1,8 @@
 import logging
 from functools import wraps
 from itertools import count
-from threading import Event, Thread
+from threading import Event, Lock, Thread
-from typing import Any, Callable, Iterable, Optional, Tuple
+from typing import Any, Callable, Iterable, Iterator, Optional, Tuple, TypeVar
 
 logger = logging.getLogger(__name__)
 
@@ -116,3 +116,19 @@ class InterruptableThreadMixin:
     def stop(self):
         """Stop a running thread."""
         self._interrupted.set()
+
+
+T = TypeVar("T")
+
+
+class ThreadSafeIterator(Iterator[T]):
+    """Provides a thread-safe iterator that wraps another iterator"""
+
+    def __init__(self, iterator: Iterator[T]):
+        self._lock = Lock()
+        self._iterator = iterator
+
+    def __next__(self) -> T:
+        while True:
+            with self._lock:
+                return next(self._iterator)

monkey/tests/unit_tests/infection_monkey/network/relay/test_utils.py

@@ -20,7 +20,7 @@ servers = [SERVER_1, SERVER_2, SERVER_3, SERVER_4]
         (
             SERVER_2,
             [(SERVER_1, {"exc": requests.exceptions.ConnectionError})]
-            + [(server, {"text": ""}) for server in servers[1:]],
+            + [(server, {"text": ""}) for server in servers[1:]],  # type: ignore[dict-item]
         ),
     ],
 )
@@ -30,3 +30,13 @@ def test_find_server(expected_server, server_response_pairs):
             mock.get(f"https://{server}/api?action=is-up", **response)
 
         assert find_server(servers) is expected_server
+
+
+def test_find_server__multiple_successes():
+    with requests_mock.Mocker() as mock:
+        mock.get(f"https://{SERVER_1}/api?action=is-up", exc=requests.exceptions.ConnectionError)
+        mock.get(f"https://{SERVER_2}/api?action=is-up", text="")
+        mock.get(f"https://{SERVER_3}/api?action=is-up", text="")
+        mock.get(f"https://{SERVER_4}/api?action=is-up", text="")
+
+        assert find_server(servers) == SERVER_2

monkey/tests/unit_tests/infection_monkey/utils/test_threading.py

@@ -1,8 +1,10 @@
 import logging
+from itertools import zip_longest
 from threading import Event, current_thread
 from typing import Any
 
 from infection_monkey.utils.threading import (
+    ThreadSafeIterator,
     create_daemon_thread,
     interruptible_function,
     interruptible_iter,
@@ -127,3 +129,11 @@ def test_interruptible_decorator_returns_default_value_on_interrupt():
 
     assert return_value == 777
     assert fn.call_count == 0
+
+
+def test_thread_safe_iterator():
+    test_list = [1, 2, 3, 4, 5]
+    tsi = ThreadSafeIterator(test_list.__iter__())
+
+    for actual, expected in zip_longest(tsi, test_list):
+        assert actual == expected