add fsspec implementation

Author: leo-schick

mara_storage/integrations/fsspec.py

@@ -0,0 +1,89 @@
+from functools import singledispatch
+import fsspec
+from fsspec.spec import AbstractFileSystem
+from typing import Union
+from mara_storage import storages
+import pathlib
+
+
+@singledispatch
+def filesystem(storage: Union[str, storages.Storage], **storage_options) -> AbstractFileSystem:
+    """
+    Returns a fsspec compatible filesystem
+
+    Args:
+        db: the storage as alias or class
+        **kargs: additional arguments to be passed to the 
+    """
+    raise NotImplementedError(f'Please implement filesystem for type "{storage.__class__.__name__}"')
+
+
+@filesystem.register(str)
+def __(storage_alias: str, **kargs):
+    return filesystem(storages.storage(storage_alias), **kargs)
+
+
+@filesystem.register(storages.LocalStorage)
+def __(storage: storages.LocalStorage, **kargs):
+    return fsspec.filesystem('file',
+                             root_marker=kargs.pop('root_marker', str(pathlib.Path(storage.base_path).absolute())),
+                             **kargs)
+
+
+@filesystem.register(storages.SftpStorage)
+def __(storage: storages.SftpStorage, **kargs):
+    return fsspec.filesystem('sftp',
+                             host=kargs.pop('host', storage.host),
+                             hostname=kargs.pop('hostname', storage.host),
+                             port=kargs.pop('port', storage.port or 22),
+                             username=kargs.pop('username', storage.user),
+                             password=kargs.pop('password', storage.password),
+                             key_filename=kargs.pop('key_filename', storage.identity_file),
+                             **kargs)
+
+
+@filesystem.register(storages.GoogleCloudStorage)
+def __(storage: storages.GoogleCloudStorage, **kargs):
+    return fsspec.filesystem('gcs',
+                             project=kargs.pop('project', storage.project_id),
+                             default_location=kargs.pop('default_location', storage.location),
+                             **kargs)
+
+
+
+@singledispatch
+def build_path(storage: Union[str, storages.Storage], path: str) -> str:
+    """
+    Builds a path for fsspec including storage specific information e.g. the
+    storage container or bucked which is defined in mara in the Storage class.
+
+    Args:
+        storage: the storage as alias or class
+        path: the path inside the storage. E.g. `my_table/*.parquet`
+
+    Returns:
+        A absolute URI or path to be used inside fsspec. E.g. `my_container/path`
+    """
+    raise NotImplementedError(f'Please implement build_uri for type "{storage.__class__.__name__}"')
+
+
+@build_path.register(str)
+def __(storage_alias: str, path: str):
+    return build_path(storages.storage(storage_alias), path=path)
+
+
+@build_path.register(storages.LocalStorage)
+def __(storage: storages.LocalStorage, path: str):
+    return str((pathlib.Path(storage.base_path) / path).absolute())
+
+
+@build_path.register(storages.GoogleCloudStorage)
+def __(storage: storages.GoogleCloudStorage, path: str):
+    if not storage.bucket_name:
+        raise ValueError(f"Storage {storage.__class__.__name__} must have a buckt name")
+    return f'{storage.bucket_name}/{path}'
+
+
+@build_path.register(storages.SftpStorage)
+def __(storage: storages.SftpStorage, path: str):
+    return path