Warn once if TTL is set

src/py/flwr/common/message.py

@@ -17,6 +17,7 @@
 from __future__ import annotations
 
 import time
+import warnings
 from dataclasses import dataclass
 
 from .record import RecordSet
@@ -311,6 +312,13 @@ def create_error_reply(self, error: Error, ttl: float | None = None) -> Message:
 
             ttl = msg.meta.ttl - (reply.meta.created_at - msg.meta.created_at)
         """
+        if ttl:
+            warnings.warn(
+                "A custom TTL was set, but note that the SuperLink does not enforce "
+                "the TTL yet. The SuperLink will start enforcing the TTL in a future "
+                "version of Flower.",
+                stacklevel=2,
+            )
         # If no TTL passed, use default for message creation (will update after
         # message creation)
         ttl_ = DEFAULT_TTL if ttl is None else ttl
@@ -349,6 +357,13 @@ def create_reply(self, content: RecordSet, ttl: float | None = None) -> Message:
         Message
             A new `Message` instance representing the reply.
         """
+        if ttl:
+            warnings.warn(
+                "A custom TTL was set, but note that the SuperLink does not enforce "
+                "the TTL yet. The SuperLink will start enforcing the TTL in a future "
+                "version of Flower.",
+                stacklevel=2,
+            )
         # If no TTL passed, use default for message creation (will update after
         # message creation)
         ttl_ = DEFAULT_TTL if ttl is None else ttl

src/py/flwr/server/driver/driver.py

@@ -14,8 +14,8 @@
 # ==============================================================================
 """Flower driver service client."""
 
-
 import time
+import warnings
 from typing import Iterable, List, Optional, Tuple
 
 from flwr.common import DEFAULT_TTL, Message, Metadata, RecordSet
@@ -91,7 +91,7 @@ def create_message(  # pylint: disable=too-many-arguments
         message_type: str,
         dst_node_id: int,
         group_id: str,
-        ttl: float = DEFAULT_TTL,
+        ttl: Optional[float] = None,
     ) -> Message:
         """Create a new message with specified parameters.
 
@@ -111,25 +111,35 @@ def create_message(  # pylint: disable=too-many-arguments
         group_id : str
             The ID of the group to which this message is associated. In some settings,
             this is used as the FL round.
-        ttl : float (default: common.DEFAULT_TTL)
+        ttl : Optional[float] (default: None)
             Time-to-live for the round trip of this message, i.e., the time from sending
             this message to receiving a reply. It specifies in seconds the duration for
-            which the message and its potential reply are considered valid.
+            which the message and its potential reply are considered valid. If unset,
+            the default TTL (i.e., `common.DEFAULT_TTL`) will be used.
 
         Returns
         -------
         message : Message
             A new `Message` instance with the specified content and metadata.
         """
         _, run_id = self._get_grpc_driver_and_run_id()
+        if ttl:
+            warnings.warn(
+                "A custom TTL was set, but note that the SuperLink does not enforce "
+                "the TTL yet. The SuperLink will start enforcing the TTL in a future "
+                "version of Flower.",
+                stacklevel=2,
+            )
+
+        ttl_ = DEFAULT_TTL if ttl is None else ttl
         metadata = Metadata(
             run_id=run_id,
             message_id="",  # Will be set by the server
             src_node_id=self.node.node_id,
             dst_node_id=dst_node_id,
             reply_to_message="",
             group_id=group_id,
-            ttl=ttl,
+            ttl=ttl_,
             message_type=message_type,
         )
         return Message(metadata=metadata, content=content)

src/py/flwr/server/workflow/default_workflows.py

@@ -21,7 +21,7 @@
 from typing import Optional, cast
 
 import flwr.common.recordset_compat as compat
-from flwr.common import DEFAULT_TTL, ConfigsRecord, Context, GetParametersIns, log
+from flwr.common import ConfigsRecord, Context, GetParametersIns, log
 from flwr.common.constant import MessageType, MessageTypeLegacy
 
 from ..compat.app_utils import start_update_client_manager_thread
@@ -127,7 +127,6 @@ def default_init_params_workflow(driver: Driver, context: Context) -> None:
                     message_type=MessageTypeLegacy.GET_PARAMETERS,
                     dst_node_id=random_client.node_id,
                     group_id="0",
-                    ttl=DEFAULT_TTL,
                 )
             ]
         )
@@ -226,7 +225,6 @@ def default_fit_workflow(  # pylint: disable=R0914
             message_type=MessageType.TRAIN,
             dst_node_id=proxy.node_id,
             group_id=str(current_round),
-            ttl=DEFAULT_TTL,
         )
         for proxy, fitins in client_instructions
     ]
@@ -306,7 +304,6 @@ def default_evaluate_workflow(driver: Driver, context: Context) -> None:
             message_type=MessageType.EVALUATE,
             dst_node_id=proxy.node_id,
             group_id=str(current_round),
-            ttl=DEFAULT_TTL,
         )
         for proxy, evalins in client_instructions
     ]

src/py/flwr/server/workflow/secure_aggregation/secaggplus_workflow.py

@@ -22,7 +22,6 @@
 
 import flwr.common.recordset_compat as compat
 from flwr.common import (
-    DEFAULT_TTL,
     ConfigsRecord,
     Context,
     FitRes,
@@ -374,7 +373,6 @@ def make(nid: int) -> Message:
                 message_type=MessageType.TRAIN,
                 dst_node_id=nid,
                 group_id=str(cfg[WorkflowKey.CURRENT_ROUND]),
-                ttl=DEFAULT_TTL,
             )
 
         log(
@@ -422,7 +420,6 @@ def make(nid: int) -> Message:
                 message_type=MessageType.TRAIN,
                 dst_node_id=nid,
                 group_id=str(cfg[WorkflowKey.CURRENT_ROUND]),
-                ttl=DEFAULT_TTL,
             )
 
         # Broadcast public keys to clients and receive secret key shares
@@ -493,7 +490,6 @@ def make(nid: int) -> Message:
                 message_type=MessageType.TRAIN,
                 dst_node_id=nid,
                 group_id=str(cfg[WorkflowKey.CURRENT_ROUND]),
-                ttl=DEFAULT_TTL,
             )
 
         log(
@@ -564,7 +560,6 @@ def make(nid: int) -> Message:
                 message_type=MessageType.TRAIN,
                 dst_node_id=nid,
                 group_id=str(current_round),
-                ttl=DEFAULT_TTL,
             )
 
         log(