refactor(framework) Update flwr new templates with new server_fn signature

src/py/flwr/cli/new/templates/app/code/server.hf.py.tpl

@@ -1,17 +1,19 @@
 """$project_name: A Flower / HuggingFace Transformers app."""
 
+from flwr.common import Context
 from flwr.server.strategy import FedAvg
-from flwr.server import ServerApp, ServerConfig
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 
 
-# Define strategy
-strategy = FedAvg(
-    fraction_fit=1.0,
-    fraction_evaluate=1.0,
-)
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg(
+        fraction_fit=1.0,
+        fraction_evaluate=1.0,
+    )
+    config = ServerConfig(num_rounds=3)
 
-# Start server
-app = ServerApp(
-    config=ServerConfig(num_rounds=3),
-    strategy=strategy,
-)
+    return ServerAppComponents(strategy=strategy, config=config)
+
+# Create ServerApp
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.jax.py.tpl

@@ -1,12 +1,16 @@
 """$project_name: A Flower / JAX app."""
 
-import flwr as fl
+from flwr.common import Context
+from flwr.server.strategy import FedAvg
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 
-# Configure the strategy
-strategy = fl.server.strategy.FedAvg()
 
-# Flower ServerApp
-app = fl.server.ServerApp(
-    config=fl.server.ServerConfig(num_rounds=3),
-    strategy=strategy,
-)
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg()
+    config = ServerConfig(num_rounds=3)
+
+    return ServerAppComponents(strategy=strategy, config=config)
+
+# Create ServerApp
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.mlx.py.tpl

@@ -1,15 +1,16 @@
 """$project_name: A Flower / MLX app."""
 
-from flwr.server import ServerApp, ServerConfig
+from flwr.common import Context
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 from flwr.server.strategy import FedAvg
 
 
-# Define strategy
-strategy = FedAvg()
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg()
+    config = ServerConfig(num_rounds=3)
 
+    return ServerAppComponents(strategy=strategy, config=config)
 
 # Create ServerApp
-app = ServerApp(
-    config=ServerConfig(num_rounds=3),
-    strategy=strategy,
-)
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.numpy.py.tpl

@@ -1,12 +1,16 @@
 """$project_name: A Flower / NumPy app."""
 
-import flwr as fl
+from flwr.common import Context
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
+from flwr.server.strategy import FedAvg
 
-# Configure the strategy
-strategy = fl.server.strategy.FedAvg()
 
-# Flower ServerApp
-app = fl.server.ServerApp(
-    config=fl.server.ServerConfig(num_rounds=1),
-    strategy=strategy,
-)
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg()
+    config = ServerConfig(num_rounds=3)
+
+    return ServerAppComponents(strategy=strategy, config=config)
+
+# Create ServerApp
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.pytorch.py.tpl

@@ -1,7 +1,7 @@
 """$project_name: A Flower / PyTorch app."""
 
-from flwr.common import ndarrays_to_parameters
-from flwr.server import ServerApp, ServerConfig
+from flwr.common import Context, ndarrays_to_parameters
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 from flwr.server.strategy import FedAvg
 
 from $import_name.task import Net, get_weights
@@ -11,18 +11,17 @@ from $import_name.task import Net, get_weights
 ndarrays = get_weights(Net())
 parameters = ndarrays_to_parameters(ndarrays)
 
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg(
+        fraction_fit=1.0,
+        fraction_evaluate=1.0,
+        min_available_clients=2,
+        initial_parameters=parameters,
+    )
+    config = ServerConfig(num_rounds=3)
 
-# Define strategy
-strategy = FedAvg(
-    fraction_fit=1.0,
-    fraction_evaluate=1.0,
-    min_available_clients=2,
-    initial_parameters=parameters,
-)
-
+    return ServerAppComponents(strategy=strategy, config=config)
 
 # Create ServerApp
-app = ServerApp(
-    config=ServerConfig(num_rounds=3),
-    strategy=strategy,
-)
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.sklearn.py.tpl

@@ -1,17 +1,20 @@
 """$project_name: A Flower / Scikit-Learn app."""
 
-from flwr.server import ServerApp, ServerConfig
+from flwr.common import Context
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 from flwr.server.strategy import FedAvg
 
 
-strategy = FedAvg(
-    fraction_fit=1.0,
-    fraction_evaluate=1.0,
-    min_available_clients=2,
-)
+def server_fn(context: Context):
+    # Define strategy
+    strategy = FedAvg(
+        fraction_fit=1.0,
+        fraction_evaluate=1.0,
+        min_available_clients=2,
+    )
+    config = ServerConfig(num_rounds=3)
+
+    return ServerAppComponents(strategy=strategy, config=config)
 
 # Create ServerApp
-app = ServerApp(
-    config=ServerConfig(num_rounds=3),
-    strategy=strategy,
-)
+app = ServerApp(server_fn=server_fn)

src/py/flwr/cli/new/templates/app/code/server.tensorflow.py.tpl

@@ -1,7 +1,7 @@
 """$project_name: A Flower / TensorFlow app."""
 
-from flwr.common import ndarrays_to_parameters
-from flwr.server import ServerApp, ServerConfig
+from flwr.common import Context, ndarrays_to_parameters
+from flwr.server import ServerApp, ServerAppComponents, ServerConfig
 from flwr.server.strategy import FedAvg
 
 from $import_name.task import load_model
@@ -11,17 +11,17 @@ config = ServerConfig(num_rounds=3)
 
 parameters = ndarrays_to_parameters(load_model().get_weights())
 
-# Define strategy
-strategy = FedAvg(
-    fraction_fit=1.0,
-    fraction_evaluate=1.0,
-    min_available_clients=2,
-    initial_parameters=parameters,
-)
+def server_fn(context: Context):
+    # Define strategy
+    strategy = strategy = FedAvg(
+        fraction_fit=1.0,
+        fraction_evaluate=1.0,
+        min_available_clients=2,
+        initial_parameters=parameters,
+    )
+    config = ServerConfig(num_rounds=3)
 
+    return ServerAppComponents(strategy=strategy, config=config)
 
 # Create ServerApp
-app = ServerApp(
-    config=config,
-    strategy=strategy,
-)
+app = ServerApp(server_fn=server_fn)