PYTHON-4579 Gossip $clusterTime from connection handshake

Author: ShaneHarvey

pymongo/asynchronous/network.py

@@ -207,6 +207,10 @@ async def command(
             )
 
             response_doc = unpacked_docs[0]
+            if not conn.ready:
+                cluster_time = response_doc.get("$clusterTime")
+                if cluster_time:
+                    conn._cluster_time = cluster_time
             if client:
                 await client._process_response(response_doc, session)
             if check:

pymongo/asynchronous/pool.py

@@ -312,6 +312,8 @@ def __init__(
         self.connect_rtt = 0.0
         self._client_id = pool._client_id
         self.creation_time = time.monotonic()
+        # For gossiping $clusterTime from the connection handshake to the client.
+        self._cluster_time = None
 
     def set_conn_timeout(self, timeout: Optional[float]) -> None:
         """Cache last timeout to avoid duplicate calls to conn.settimeout."""
@@ -1304,6 +1306,9 @@ async def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> A
             conn.close_conn(ConnectionClosedReason.ERROR)
             raise
 
+        if handler:
+            await handler.client._topology.receive_cluster_time(conn._cluster_time)
+
         return conn
 
     @contextlib.asynccontextmanager

pymongo/synchronous/network.py

@@ -207,6 +207,10 @@ def command(
             )
 
             response_doc = unpacked_docs[0]
+            if not conn.ready:
+                cluster_time = response_doc.get("$clusterTime")
+                if cluster_time:
+                    conn._cluster_time = cluster_time
             if client:
                 client._process_response(response_doc, session)
             if check:

pymongo/synchronous/pool.py

@@ -312,6 +312,8 @@ def __init__(
         self.connect_rtt = 0.0
         self._client_id = pool._client_id
         self.creation_time = time.monotonic()
+        # For gossiping $clusterTime from the connection handshake to the client.
+        self._cluster_time = None
 
     def set_conn_timeout(self, timeout: Optional[float]) -> None:
         """Cache last timeout to avoid duplicate calls to conn.settimeout."""
@@ -1298,6 +1300,9 @@ def connect(self, handler: Optional[_MongoClientErrorHandler] = None) -> Connect
             conn.close_conn(ConnectionClosedReason.ERROR)
             raise
 
+        if handler:
+            handler.client._topology.receive_cluster_time(conn._cluster_time)
+
         return conn
 
     @contextlib.contextmanager