fix: remote python client closes idle connections (#831)

python/lancedb/remote/client.py

@@ -24,6 +24,7 @@ from pydantic import BaseModel
 from lancedb.common import Credential
 from lancedb.remote import VectorQuery, VectorQueryResult
 from lancedb.remote.errors import LanceDBClientError
+from lancedb.remote.connection_timeout import LanceDBClientHTTPAdapterFactory
 
 ARROW_STREAM_CONTENT_TYPE = "application/vnd.apache.arrow.stream"
 
@@ -55,7 +56,10 @@ class RestfulLanceDBClient:
 
     @functools.cached_property
     def session(self) -> requests.Session:
-        return requests.Session()
+        sess = requests.Session()
+        adapter_class = LanceDBClientHTTPAdapterFactory()
+        sess.mount("https://", adapter_class())
+        return sess
 
     @property
     def url(self) -> str:

python/lancedb/remote/connection_timeout.py

@@ -0,0 +1,115 @@
+#  Copyright 2024 LanceDB Developers
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+# This module contains an adapter that will close connections if they have not been
+# used before a certain timeout. This is necessary because some load balancers will
+# close connections after a certain amount of time, but the request module may not yet
+# have received the FIN/ACK and will try to reuse the connection.
+#
+# TODO some of the code here can be simplified if/when this PR is merged:
+# https://github.com/urllib3/urllib3/pull/3275
+
+import datetime
+import os
+import logging
+
+from requests.adapters import HTTPAdapter
+from urllib3.poolmanager import PoolManager
+from urllib3.connectionpool import HTTPSConnectionPool
+from urllib3.connection import HTTPSConnection
+
+
+def get_client_connection_timeout() -> int:
+    return int(os.environ.get("LANCE_CLIENT_CONNECTION_TIMEOUT", "300"))
+
+
+class LanceDBHTTPSConnection(HTTPSConnection):
+    """
+    HTTPSConnection that tracks the last time it was used.
+    """
+
+    idle_timeout: datetime.timedelta
+    last_activity: datetime.datetime
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.last_activity = datetime.datetime.now()
+
+    def request(self, *args, **kwargs):
+        self.last_activity = datetime.datetime.now()
+        super().request(*args, **kwargs)
+
+    def is_expired(self):
+        return datetime.datetime.now() - self.last_activity > self.idle_timeout
+
+
+def LanceDBHTTPSConnectionPoolFactory(client_idle_timeout: int):
+    """
+    Creates a connection pool class that can be used to close idle connections.
+    """
+
+    class LanceDBHTTPSConnectionPool(HTTPSConnectionPool):
+        # override the connection class
+        ConnectionCls = LanceDBHTTPSConnection
+
+        def __init__(self, *args, **kwargs):
+            super().__init__(*args, **kwargs)
+
+        def _get_conn(self, timeout: float | None = None):
+            logging.debug("Getting https connection")
+            conn = super()._get_conn(timeout)
+            if conn.is_expired():
+                logging.debug("Closing expired connection")
+                conn.close()
+
+            return conn
+
+        def _new_conn(self):
+            conn = super()._new_conn()
+            conn.idle_timeout = datetime.timedelta(seconds=client_idle_timeout)
+            return conn
+
+    return LanceDBHTTPSConnectionPool
+
+
+class LanceDBClientPoolManager(PoolManager):
+    def __init__(
+        self, client_idle_timeout: int, num_pools: int, maxsize: int, **kwargs
+    ):
+        super().__init__(num_pools=num_pools, maxsize=maxsize, **kwargs)
+        # inject our connection pool impl
+        connection_pool_class = LanceDBHTTPSConnectionPoolFactory(
+            client_idle_timeout=client_idle_timeout
+        )
+        self.pool_classes_by_scheme["https"] = connection_pool_class
+
+
+def LanceDBClientHTTPAdapterFactory():
+    """
+    Creates an HTTPAdapter class that can be used to close idle connections
+    """
+
+    # closure over the timeout
+    client_idle_timeout = get_client_connection_timeout()
+
+    class LanceDBClientRequestHTTPAdapter(HTTPAdapter):
+        def init_poolmanager(self, connections, maxsize, block=False):
+            # inject our pool manager impl
+            self.poolmanager = LanceDBClientPoolManager(
+                client_idle_timeout=client_idle_timeout,
+                num_pools=connections,
+                maxsize=maxsize,
+                block=block,
+            )
+
+    return LanceDBClientRequestHTTPAdapter