feat(datasets): Add flwr-datasets create CLI

datasets/flwr_datasets/cli/__init__.py

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+# Copyright 2026 Flower Labs GmbH. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Flower Ddatasets command line interface."""

datasets/flwr_datasets/cli/app.py

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+# Copyright 2026 Flower Labs GmbH. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Flower Datasets command line interface."""
+
+
+import typer
+from typer.main import get_command
+
+from flwr_datasets.common.version import package_version
+
+from .create import create
+
+app = typer.Typer(
+    help=typer.style(
+        "flwr-datasets is the Flower Datasets command line interface.",
+        fg=typer.colors.BRIGHT_YELLOW,
+        bold=True,
+    ),
+    no_args_is_help=True,
+    context_settings={"help_option_names": ["-h", "--help"]},
+)
+
+app.command()(create)
+
+typer_click_object = get_command(app)
+
+
+@app.callback(invoke_without_command=True)
+def main(
+    version: bool = typer.Option(
+        None,
+        "-V",
+        "--version",
+        is_eager=True,
+        help="Show the version and exit.",
+    ),
+) -> None:
+    """Flower Datasets CLI."""
+    if version:
+        typer.secho(f"Flower Datasets version: {package_version}", fg="blue")
+        raise typer.Exit()
+
+
+if __name__ == "__main__":
+    app()

datasets/flwr_datasets/cli/create.py

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+# Copyright 2026 Flower Labs GmbH. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Flower Datasets command line interface `create` command."""
+
+
+from pathlib import Path
+from typing import Annotated
+
+import click
+import typer
+
+from datasets.load import DatasetNotFoundError
+from flwr_datasets import FederatedDataset
+from flwr_datasets.partitioner import IidPartitioner
+
+
+def create(
+    dataset_name: Annotated[
+        str,
+        typer.Argument(
+            help="Hugging Face dataset identifier (e.g., 'ylecun/mnist').",
+        ),
+    ],
+    num_partitions: Annotated[
+        int,
+        typer.Option(
+            "--num-partitions",
+            help="Number of partitions to create. Must be a positive integer",
+        ),
+    ] = 10,
+    out_dir: Annotated[
+        Path,
+        typer.Option(
+            "--out-dir",
+            help="Output directory for the federated dataset.",
+        ),
+    ] = Path("./federated_dataset"),
+) -> None:
+    """Create a federated dataset and save each partition in a sub-directory.
+
+    This command is used to generate federated datasets
+    for demo purposes and currently supports only IID
+    partitioning `IidPartitioner`.
+    """
+    # Validate number of partitions
+    if num_partitions <= 0:
+        raise click.ClickException("--num-partitions must be a positive integer.")
+
+    # Handle output directory
+    if out_dir.exists():
+        overwrite = typer.confirm(
+            typer.style(
+                f"\n💬 {out_dir} already exists, do you want to override it?",
+                fg=typer.colors.MAGENTA,
+                bold=True,
+            ),
+            default=False,
+        )
+        if not overwrite:
+            return
+
+    out_dir.mkdir(parents=True, exist_ok=True)
+
+    # Create data partitioner
+    partitioner = IidPartitioner(num_partitions=num_partitions)
+
+    try:
+        # Create the federated dataset
+        fds = FederatedDataset(
+            dataset=dataset_name,
+            partitioners={"train": partitioner},
+        )
+
+        # Load partitions and save them to disk
+        for partition_id in range(num_partitions):
+            partition = fds.load_partition(partition_id=partition_id)
+            partition_out_dir = out_dir / f"partition_{partition_id}"
+            partition.save_to_disk(partition_out_dir)
+
+    except DatasetNotFoundError as err:
+        raise click.ClickException(
+            f"Dataset '{dataset_name}' could not be found on the Hugging Face Hub, "
+            "or network access is unavailable. "
+            "Please verify the dataset identifier and your internet connection."
+        ) from err
+
+    except Exception as ex:  # pylint: disable=broad-exception-caught
+        raise click.ClickException(
+            "An unexpected error occurred while creating the federated dataset. "
+            f"Please try again or check the logs for more details: {str(ex)}"
+        ) from ex
+
+    typer.secho(
+        f"🎊 Created {num_partitions} partitions for '{dataset_name}' in '{out_dir.absolute()}'",
+        fg=typer.colors.GREEN,
+        bold=True,
+    )