Handle asyncio.TimeoutError for link validation code (#1051)

Handle asyncio.TimeoutError

Author: sarayourfriend

api/catalog/api/utils/validate_images.py

@@ -33,9 +33,9 @@ def _get_expiry(status, default):
 
 async def _head(url: str, session: aiohttp.ClientSession) -> tuple[str, int]:
     try:
-        async with session.head(url, timeout=2, allow_redirects=False) as response:
+        async with session.head(url, allow_redirects=False) as response:
             return url, response.status
-    except aiohttp.ClientError as exception:
+    except (aiohttp.ClientError, asyncio.TimeoutError) as exception:
         _log_validation_failure(exception)
         return url, -1
 
@@ -44,7 +44,8 @@ async def _head(url: str, session: aiohttp.ClientSession) -> tuple[str, int]:
 @async_to_sync
 async def _make_head_requests(urls: list[str]) -> list[tuple[str, int]]:
     tasks = []
-    async with aiohttp.ClientSession(headers=HEADERS) as session:
+    timeout = aiohttp.ClientTimeout(total=2)
+    async with aiohttp.ClientSession(headers=HEADERS, timeout=timeout) as session:
         tasks = [asyncio.ensure_future(_head(url, session)) for url in urls]
         responses = asyncio.gather(*tasks)
         await responses

api/test/unit/utils/validate_images_test.py

@@ -1,3 +1,4 @@
+import asyncio
 from unittest import mock
 
 import aiohttp
@@ -43,4 +44,27 @@ def test_sends_user_agent(wrapped_client_session: mock.AsyncMock):
     for url in image_urls:
         assert url in requested_urls
 
-    wrapped_client_session.assert_called_once_with(headers=HEADERS)
+    wrapped_client_session.assert_called_once_with(headers=HEADERS, timeout=mock.ANY)
+
+
+def test_handles_timeout():
+    """
+    Note: This test takes just over 3 seconds to run as it simulates network delay of 3 seconds.
+    """
+    query_hash = "test_handles_timeout"
+    results = [{"identifier": i} for i in range(1)]
+    image_urls = [f"https://example.org/{i}" for i in range(len(results))]
+    start_slice = 0
+
+    def raise_timeout_error(*args, **kwargs):
+        raise asyncio.TimeoutError()
+
+    with mock.patch(
+        "aiohttp.client.ClientSession._request", side_effect=raise_timeout_error
+    ):
+        validate_images(query_hash, start_slice, results, image_urls)
+
+    # `validate_images` directly modifies the results list
+    # if the results are timing out then they're considered dead and discarded
+    # so should not appear in the final list of results.
+    assert len(results) == 0