Add MessageType

src/py/flwr/common/__init__.py

@@ -15,6 +15,7 @@
 """Common components shared between server and client."""
 
 
+from .constant import MessageType as MessageType
 from .context import Context as Context
 from .date import now as now
 from .grpc import GRPC_MAX_MESSAGE_LENGTH
@@ -83,6 +84,7 @@
     "GRPC_MAX_MESSAGE_LENGTH",
     "log",
     "Message",
+    "MessageType",
     "Metadata",
     "Metrics",
     "MetricsAggregationFn",

src/py/flwr/common/constant.py

@@ -42,6 +42,17 @@
 MESSAGE_TYPE_EVALUATE = "evaluate"
 
 
+class MessageType:
+    """Message type."""
+
+    TRAIN = "train"
+    EVALUATE = "evaluate"
+
+    def __new__(cls) -> MessageType:
+        """Prevent instantiation."""
+        raise TypeError(f"{cls.__name__} cannot be instantiated.")
+
+
 class SType:
     """Serialisation type."""