Add created_at to Metadata

src/proto/flwr/proto/task.proto

@@ -25,7 +25,7 @@ import "flwr/proto/error.proto";
 message Task {
   Node producer = 1;
   Node consumer = 2;
-  string created_at = 3;
+  double created_at = 3;
   string delivered_at = 4;
   double pushed_at = 5;
   double ttl = 6;

src/py/flwr/client/message_handler/message_handler.py

@@ -172,6 +172,7 @@ def validate_out_message(out_message: Message, in_message_metadata: Metadata) ->
         and out_meta.reply_to_message == in_meta.message_id
         and out_meta.group_id == in_meta.group_id
         and out_meta.message_type == in_meta.message_type
+        and out_meta.created_at > in_meta.created_at
     ):
         return True
     return False

src/py/flwr/client/message_handler/message_handler_test.py

@@ -15,6 +15,7 @@
 """Client-side message handler tests."""
 
 
+import time
 import unittest
 import uuid
 from copy import copy
@@ -169,7 +170,18 @@ def test_client_without_get_properties() -> None:
     )
 
     assert actual_msg.content == expected_msg.content
-    assert actual_msg.metadata == expected_msg.metadata
+    # metadata.created_at will differ so let's exclude it from checks
+    attrs = actual_msg.metadata.__annotations__
+    attrs_keys = list(attrs.keys())
+    attrs_keys.remove("_created_at")
+    # metadata.created_at will differ so let's exclude it from checks
+    for attr in attrs_keys:
+        assert getattr(actual_msg.metadata, attr) == getattr(
+            expected_msg.metadata, attr
+        )
+
+    # Ensure the message created last has a higher timestamp
+    assert actual_msg.metadata.created_at < expected_msg.metadata.created_at
 
 
 def test_client_with_get_properties() -> None:
@@ -222,7 +234,17 @@ def test_client_with_get_properties() -> None:
     )
 
     assert actual_msg.content == expected_msg.content
-    assert actual_msg.metadata == expected_msg.metadata
+    attrs = actual_msg.metadata.__annotations__
+    attrs_keys = list(attrs.keys())
+    attrs_keys.remove("_created_at")
+    # metadata.created_at will differ so let's exclude it from checks
+    for attr in attrs_keys:
+        assert getattr(actual_msg.metadata, attr) == getattr(
+            expected_msg.metadata, attr
+        )
+
+    # Ensure the message created last has a higher timestamp
+    assert actual_msg.metadata.created_at < expected_msg.metadata.created_at
 
 
 class TestMessageValidation(unittest.TestCase):
@@ -241,6 +263,11 @@ def setUp(self) -> None:
             ttl=DEFAULT_TTL,
             message_type="mock",
         )
+        # We need to set created_at in this way
+        # since this `self.in_metadata` is used for tests
+        # without it ever being part of a Message
+        self.in_metadata.created_at = time.time()
+
         self.valid_out_metadata = Metadata(
             run_id=123,
             message_id="",
@@ -281,6 +308,10 @@ def test_invalid_message_run_id(self) -> None:
                 value = 999
             elif isinstance(value, str):
                 value = "999"
+            elif isinstance(value, float):
+                if attr == "_created_at":
+                    # make it be in 1h the past
+                    value = value - 3600
             setattr(invalid_metadata, attr, value)
             # Add to list
             invalid_metadata_list.append(invalid_metadata)

src/py/flwr/common/message.py

@@ -16,6 +16,7 @@
 
 from __future__ import annotations
 
+import time
 from dataclasses import dataclass
 
 from .record import RecordSet
@@ -62,6 +63,7 @@ class Metadata:  # pylint: disable=too-many-instance-attributes
     _ttl: float
     _message_type: str
     _partition_id: int | None
+    _created_at: float  # Unix timestamp (in seconds) to be set upon message creation
 
     def __init__(  # pylint: disable=too-many-arguments
         self,
@@ -125,6 +127,16 @@ def group_id(self, value: str) -> None:
         """Set group_id."""
         self._group_id = value
 
+    @property
+    def created_at(self) -> float:
+        """Unix timestamp when the message was created."""
+        return self._created_at
+
+    @created_at.setter
+    def created_at(self, value: float) -> None:
+        """Set creation timestamp for this messages."""
+        self._created_at = value
+
     @property
     def ttl(self) -> float:
         """Time-to-live for this message."""
@@ -214,6 +226,9 @@ def __init__(
     ) -> None:
         self._metadata = metadata
 
+        # Set message creation timestamp
+        self._metadata.created_at = time.time()
+
         if not (content is None) ^ (error is None):
             raise ValueError("Either `content` or `error` must be set, but not both.")
 

src/py/flwr/common/message_test.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 """Message tests."""
 
-
+import time
 from contextlib import ExitStack
 from typing import Any, Callable
 
@@ -62,12 +62,15 @@ def test_message_creation(
         if context:
             stack.enter_context(context)
 
-        _ = Message(
+        message = Message(
             metadata=metadata,
             content=None if content_fn is None else content_fn(maker),
             error=None if error_fn is None else error_fn(0),
         )
 
+        assert message.metadata.created_at > 0
+        assert message.metadata.created_at < time.time()
+
 
 def create_message_with_content() -> Message:
     """Create a Message with content."""

src/py/flwr/common/serde.py

@@ -575,6 +575,7 @@ def message_to_taskins(message: Message) -> TaskIns:
         task=Task(
             producer=Node(node_id=0, anonymous=True),  # Assume driver node
             consumer=Node(node_id=md.dst_node_id, anonymous=False),
+            created_at=md.created_at,
             ttl=md.ttl,
             ancestry=[md.reply_to_message] if md.reply_to_message != "" else [],
             task_type=md.message_type,
@@ -601,7 +602,7 @@ def message_from_taskins(taskins: TaskIns) -> Message:
     )
 
     # Construct Message
-    return Message(
+    message = Message(
         metadata=metadata,
         content=(
             recordset_from_proto(taskins.task.recordset)
@@ -614,6 +615,8 @@ def message_from_taskins(taskins: TaskIns) -> Message:
             else None
         ),
     )
+    message.metadata.created_at = taskins.task.created_at
+    return message
 
 
 def message_to_taskres(message: Message) -> TaskRes:
@@ -626,6 +629,7 @@ def message_to_taskres(message: Message) -> TaskRes:
         task=Task(
             producer=Node(node_id=md.src_node_id, anonymous=False),
             consumer=Node(node_id=0, anonymous=True),  # Assume driver node
+            created_at=md.created_at,
             ttl=md.ttl,
             ancestry=[md.reply_to_message] if md.reply_to_message != "" else [],
             task_type=md.message_type,
@@ -652,7 +656,7 @@ def message_from_taskres(taskres: TaskRes) -> Message:
     )
 
     # Construct the Message
-    return Message(
+    message = Message(
         metadata=metadata,
         content=(
             recordset_from_proto(taskres.task.recordset)
@@ -665,3 +669,6 @@ def message_from_taskres(taskres: TaskRes) -> Message:
             else None
         ),
     )
+
+    message.metadata.created_at = taskres.task.created_at
+    return message

src/py/flwr/proto/task_pb2.pyi

@@ -30,7 +30,7 @@ class Task(google.protobuf.message.Message):
     def producer(self) -> flwr.proto.node_pb2.Node: ...
     @property
     def consumer(self) -> flwr.proto.node_pb2.Node: ...
-    created_at: typing.Text
+    created_at: builtins.float
     delivered_at: typing.Text
     pushed_at: builtins.float
     ttl: builtins.float
@@ -45,7 +45,7 @@ class Task(google.protobuf.message.Message):
         *,
         producer: typing.Optional[flwr.proto.node_pb2.Node] = ...,
         consumer: typing.Optional[flwr.proto.node_pb2.Node] = ...,
-        created_at: typing.Text = ...,
+        created_at: builtins.float = ...,
         delivered_at: typing.Text = ...,
         pushed_at: builtins.float = ...,
         ttl: builtins.float = ...,

src/py/flwr/server/compat/driver_client_proxy.py

@@ -132,6 +132,13 @@ def _send_receive_recordset(
                 ttl=DEFAULT_TTL,
             ),
         )
+
+        # This would normally be recorded upon common.Message creation
+        # but this compatibility stack doesn't create Messages,
+        # so we need to inject `created_at` manually (needed for
+        # taskins validation by server.utils.validator)
+        task_ins.task.created_at = time.time()
+
         push_task_ins_req = driver_pb2.PushTaskInsRequest(  # pylint: disable=E1101
             task_ins_list=[task_ins]
         )

src/py/flwr/server/superlink/state/in_memory_state.py

@@ -17,7 +17,6 @@
 
 import os
 import threading
-from datetime import datetime
 from logging import ERROR
 from typing import Dict, List, Optional, Set
 from uuid import UUID, uuid4
@@ -50,13 +49,11 @@ def store_task_ins(self, task_ins: TaskIns) -> Optional[UUID]:
             log(ERROR, "`run_id` is invalid")
             return None
 
-        # Create task_id and created_at
+        # Create task_id
         task_id = uuid4()
-        created_at: datetime = now()
 
         # Store TaskIns
         task_ins.task_id = str(task_id)
-        task_ins.task.created_at = created_at.isoformat()
         with self.lock:
             self.task_ins_store[task_id] = task_ins
 
@@ -111,13 +108,11 @@ def store_task_res(self, task_res: TaskRes) -> Optional[UUID]:
             log(ERROR, "`run_id` is invalid")
             return None
 
-        # Create task_id and created_at
+        # Create task_id
         task_id = uuid4()
-        created_at: datetime = now()
 
         # Store TaskRes
         task_res.task_id = str(task_id)
-        task_res.task.created_at = created_at.isoformat()
         with self.lock:
             self.task_res_store[task_id] = task_res
 

src/py/flwr/server/superlink/state/sqlite_state.py

@@ -18,7 +18,6 @@
 import os
 import re
 import sqlite3
-from datetime import datetime
 from logging import DEBUG, ERROR
 from typing import Any, Dict, List, Optional, Set, Tuple, Union, cast
 from uuid import UUID, uuid4
@@ -52,7 +51,7 @@
     producer_node_id        INTEGER,
     consumer_anonymous      BOOLEAN,
     consumer_node_id        INTEGER,
-    created_at              TEXT,
+    created_at              REAL,
     delivered_at            TEXT,
     pushed_at               REAL,
     ttl                     REAL,
@@ -73,7 +72,7 @@
     producer_node_id        INTEGER,
     consumer_anonymous      BOOLEAN,
     consumer_node_id        INTEGER,
-    created_at              TEXT,
+    created_at              REAL,
     delivered_at            TEXT,
     pushed_at               REAL,
     ttl                     REAL,
@@ -187,13 +186,11 @@ def store_task_ins(self, task_ins: TaskIns) -> Optional[UUID]:
             log(ERROR, errors)
             return None
 
-        # Create task_id and created_at
+        # Create task_id
         task_id = uuid4()
-        created_at: datetime = now()
 
         # Store TaskIns
         task_ins.task_id = str(task_id)
-        task_ins.task.created_at = created_at.isoformat()
         data = (task_ins_to_dict(task_ins),)
         columns = ", ".join([f":{key}" for key in data[0]])
         query = f"INSERT INTO task_ins VALUES({columns});"
@@ -322,11 +319,9 @@ def store_task_res(self, task_res: TaskRes) -> Optional[UUID]:
 
         # Create task_id
         task_id = uuid4()
-        created_at: datetime = now()
 
         # Store TaskIns
         task_res.task_id = str(task_id)
-        task_res.task.created_at = created_at.isoformat()
         data = (task_res_to_dict(task_res),)
         columns = ", ".join([f":{key}" for key in data[0]])
         query = f"INSERT INTO task_res VALUES({columns});"

src/py/flwr/server/superlink/state/state_test.py

@@ -73,7 +73,7 @@ def test_store_task_ins_one(self) -> None:
             consumer_node_id=consumer_node_id, anonymous=False, run_id=run_id
         )
 
-        assert task_ins.task.created_at == ""  # pylint: disable=no-member
+        assert task_ins.task.created_at < time.time()  # pylint: disable=no-member
         assert task_ins.task.delivered_at == ""  # pylint: disable=no-member
 
         # Execute
@@ -90,12 +90,9 @@ def test_store_task_ins_one(self) -> None:
 
         actual_task = actual_task_ins.task
 
-        assert actual_task.created_at != ""
         assert actual_task.delivered_at != ""
 
-        assert datetime.fromisoformat(actual_task.created_at) > datetime(
-            2020, 1, 1, tzinfo=timezone.utc
-        )
+        assert actual_task.created_at < actual_task.pushed_at
         assert datetime.fromisoformat(actual_task.delivered_at) > datetime(
             2020, 1, 1, tzinfo=timezone.utc
         )
@@ -419,6 +416,7 @@ def create_task_ins(
             task_type="mock",
             recordset=RecordSet(parameters={}, metrics={}, configs={}),
             ttl=DEFAULT_TTL,
+            created_at=time.time(),
         ),
     )
     task.task.pushed_at = time.time()
@@ -443,6 +441,7 @@ def create_task_res(
             task_type="mock",
             recordset=RecordSet(parameters={}, metrics={}, configs={}),
             ttl=DEFAULT_TTL,
+            created_at=time.time(),
         ),
     )
     task_res.task.pushed_at = time.time()

src/py/flwr/server/utils/validator.py

@@ -32,8 +32,13 @@ def validate_task_ins_or_res(tasks_ins_res: Union[TaskIns, TaskRes]) -> List[str
         validation_errors.append("`task` does not set field `task`")
 
     # Created/delivered/TTL/Pushed
-    if tasks_ins_res.task.created_at != "":
-        validation_errors.append("`created_at` must be an empty str")
+    if (
+        tasks_ins_res.task.created_at < 1711497600.0
+    ):  # unix timestamp of 27 March 2024 00h:00m:00s UTC
+        validation_errors.append(
+            "`created_at` must be a float that records the unix timestamp "
+            "in seconds when the message was created."
+        )
     if tasks_ins_res.task.delivered_at != "":
         validation_errors.append("`delivered_at` must be an empty str")
     if tasks_ins_res.task.ttl <= 0: