feat(framework:skip) Add Flower File Storage interface and disk based implementation

src/py/flwr/server/superlink/ffs/__init__.py

@@ -0,0 +1,24 @@
+# Copyright 2024 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 File Storage for large objects."""
+
+
+from .disk_ffs import DiskFfs as DiskFfs
+from .ffs import Ffs as Ffs
+
+__all__ = [
+    "DiskFfs",
+    "Ffs",
+]

src/py/flwr/server/superlink/ffs/disk_ffs.py

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+# Copyright 2024 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.
+# ==============================================================================
+"""Disk based Flower File Storage."""
+
+import hashlib
+import json
+from pathlib import Path
+from typing import Dict, List, Tuple
+
+from flwr.server.superlink.ffs.ffs import Ffs
+
+
+class DiskFfs(Ffs):  # pylint: disable=R0904
+    """Disk based Flower File Storage interface for large objects."""
+
+    def __init__(self, base_dir: str) -> None:
+        """Create a new DiskFfs instance.
+
+        Parameters
+        ----------
+        base_dir : str
+            The base directory to store the objects.
+        """
+        self.base_dir = Path(base_dir)
+
+    def put(self, content: bytes, meta: Dict[str, str]) -> str:
+        """Store bytes and metadata and returns sha256hex hash of data as str.
+
+        Parameters
+        ----------
+        content : bytes
+            The content to be stored.
+        meta : Dict[str, str]
+            The metadata to be stored.
+
+        Returns
+        -------
+        str
+            The key (sha256hex hash) of the content.
+        """
+        content_hash = hashlib.sha256(content).hexdigest()
+
+        self.base_dir.mkdir(exist_ok=True, parents=True)
+        (self.base_dir / content_hash).write_bytes(content)
+        (self.base_dir / f"{content_hash}.META").write_text(json.dumps(meta))
+
+        return content_hash
+
+    def get(self, key: str) -> Tuple[bytes, Dict[str, str]]:
+        """Return tuple containing the object content and metadata.
+
+        Parameters
+        ----------
+        key : str
+            The sha256hex hash of the object to be retrieved.
+
+        Returns
+        -------
+        Tuple[bytes, Dict[str, str]]
+            A tuple containing the object content and metadata.
+        """
+        content = (self.base_dir / key).read_bytes()
+        meta = json.loads((self.base_dir / f"{key}.META").read_text())
+
+        return content, meta
+
+    def delete(self, key: str) -> None:
+        """Delete object with hash.
+
+        Parameters
+        ----------
+        key : str
+            The sha256hex hash of the object to be deleted.
+        """
+        (self.base_dir / key).unlink()
+        (self.base_dir / f"{key}.META").unlink()
+
+    def list(self) -> List[str]:
+        """List all keys.
+
+        Can be used to list all keys in the storage and e.g. to clean up
+        the storage with the delete method.
+
+        Returns
+        -------
+        List[str]
+            A list of all available keys.
+        """
+        return [
+            item.name for item in self.base_dir.iterdir() if not item.suffix == ".META"
+        ]

src/py/flwr/server/superlink/ffs/ffs.py

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+# Copyright 2024 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.
+# ==============================================================================
+"""Abstract base class for Flower File Storage interface."""
+
+
+import abc
+from typing import Dict, List, Tuple
+
+
+class Ffs(abc.ABC):  # pylint: disable=R0904
+    """Abstract Flower File Storage interface for large objects."""
+
+    @abc.abstractmethod
+    def put(self, content: bytes, meta: Dict[str, str]) -> str:
+        """Store bytes and metadata and return sha256hex hash of data as str.
+
+        Parameters
+        ----------
+        content : bytes
+            The content to be stored.
+        meta : Dict[str, str]
+            The metadata to be stored.
+
+        Returns
+        -------
+        str
+            The key (sha256hex hash) of the content.
+        """
+
+    @abc.abstractmethod
+    def get(self, key: str) -> Tuple[bytes, Dict[str, str]]:
+        """Return tuple containing the object content and metadata.
+
+        Parameters
+        ----------
+        key : str
+            The key (sha256hex hash) of the object to be retrieved.
+
+        Returns
+        -------
+        Tuple[bytes, Dict[str, str]]
+            A tuple containing the object content and metadata.
+        """
+
+    @abc.abstractmethod
+    def delete(self, key: str) -> None:
+        """Delete object with hash.
+
+        Parameters
+        ----------
+        key : str
+            The key (sha256hex hash) of the object to be deleted.
+        """
+
+    @abc.abstractmethod
+    def list(self) -> List[str]:
+        """List keys of all stored objects.
+
+        Return all available keys in this `Ffs` instance.
+        This can be combined with, for example,
+        the `delete` method to delete objects.
+
+        Returns
+        -------
+        List[str]
+            A list of all available keys.
+        """

src/py/flwr/server/superlink/ffs/ffs_factory.py

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+# Copyright 2024 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.
+# ==============================================================================
+"""Factory class that creates Ffs instances."""
+
+
+from logging import DEBUG
+from typing import Optional
+
+from flwr.common.logger import log
+
+from .disk_ffs import DiskFfs
+from .ffs import Ffs
+
+
+class FfsFactory:
+    """Factory class that creates Ffs instances.
+
+    Parameters
+    ----------
+    base_dir : str
+        The base directory to store the objects.
+    """
+
+    def __init__(self, base_dir: str) -> None:
+        self.base_dir = base_dir
+        self.ffs_instance: Optional[Ffs] = None
+
+    def ffs(self) -> Ffs:
+        """Return a Ffs instance and create it, if necessary."""
+        # SqliteState
+        ffs = DiskFfs(self.base_dir)
+        log(DEBUG, "Using Disk Flower File System")
+        return ffs