feat: add max round trip latency

Author: 1egoman

livekit-rtc/livekit/rtc/participant.py

@@ -59,6 +59,13 @@
 from ._proto import data_track_pb2 as proto_data_track
 
 
+# Default maximum amount of time it should ever take for an RPC request to reach the
+# destination and for the ACK to come back. Set to 7 seconds to account for various
+# relay timeouts and retries in LiveKit Cloud that occur in rare cases. Most callers
+# should not need to change this.
+DEFAULT_MAX_ROUND_TRIP_LATENCY = 7.0
+
+
 class PublishTrackError(Exception):
     def __init__(self, message: str) -> None:
         self.message = message
@@ -324,6 +331,7 @@ async def perform_rpc(
         method: str,
         payload: str,
         response_timeout: Optional[float] = None,
+        max_round_trip_latency: float = DEFAULT_MAX_ROUND_TRIP_LATENCY,
     ) -> str:
         """
         Initiate an RPC call to a remote participant.
@@ -333,6 +341,12 @@ async def perform_rpc(
             method (str): The method name to call
             payload (str): The method payload
             response_timeout (Optional[float]): Timeout for receiving a response after initial connection
+            max_round_trip_latency (float): The maximum amount of time it should ever take for an RPC
+                request to reach the destination and for the ACK to come back. Defaults to 7 seconds to
+                account for various relay timeouts and retries in LiveKit Cloud that occur in rare cases.
+                Most callers should not need to change this, but it can be increased to tolerate
+                high-latency networks where RPC requests are backed up behind other messages on the
+                data channel.
 
         Returns:
             str: The response payload
@@ -347,6 +361,7 @@ async def perform_rpc(
         req.perform_rpc.payload = payload
         if response_timeout is not None:
             req.perform_rpc.response_timeout_ms = int(response_timeout * 1000)
+        req.perform_rpc.max_round_trip_latency_ms = int(max_round_trip_latency * 1000)
 
         queue = FfiClient.instance.queue.subscribe()
         try: