Refactor maybe_create_object_store_from_uri (#3679)

composer/utils/file_helpers.py

@@ -12,7 +12,7 @@
 import tempfile
 import uuid
 import warnings
-from typing import TYPE_CHECKING, Any, Optional, Union
+from typing import TYPE_CHECKING, Any, Callable, Optional, Union
 from urllib.parse import urlparse
 
 import requests
@@ -393,13 +393,31 @@ def parse_uri(uri: str) -> tuple[str, str, str]:
         return backend, bucket_name, path.lstrip('/')
 
 
+# Dictionary mapping backend names to ObjectStore factory functions
+BACKEND_TO_OBJECT_STORE_FACTORY: dict[str, Callable[[str, str], ObjectStore]] = {
+    's3':
+        lambda bucket, path: S3ObjectStore(bucket=bucket),
+    'gs':
+        lambda bucket, path: GCSObjectStore(bucket=bucket),
+    'oci':
+        lambda bucket, path: OCIObjectStore(bucket=bucket),
+    'azure':
+        lambda bucket, path: LibcloudObjectStore(
+            provider='AZURE_BLOBS',
+            container=bucket,
+            key_environ='AZURE_ACCOUNT_NAME',
+            secret_environ='AZURE_ACCOUNT_ACCESS_KEY',
+        ),
+}
+
+
 def maybe_create_object_store_from_uri(uri: str) -> Optional[ObjectStore]:
     """Automatically creates an :class:`composer.utils.ObjectStore` from supported URI formats.
 
     Currently supported backends are ``s3://``, ``oci://``, and local paths (in which case ``None`` will be returned)
 
     Args:
-        uri (str): The path to (maybe) create an :class:`composer.utils.ObjectStore` from
+        uri (str): The path to (maybe) create an :class:`composer.utils.ObjectStore` from.
 
     Raises:
         NotImplementedError: Raises when the URI format is not supported.
@@ -408,25 +426,15 @@ def maybe_create_object_store_from_uri(uri: str) -> Optional[ObjectStore]:
         Optional[ObjectStore]: Returns an :class:`composer.utils.ObjectStore` if the URI is of a supported format, otherwise None
     """
     backend, bucket_name, path = parse_uri(uri)
+
+    # If backend is empty, assume local path and return None
     if backend == '':
         return None
-    if backend == 's3':
-        return S3ObjectStore(bucket=bucket_name)
+
+    # Handle special cases like WandB, MLFlow, etc.
     elif backend == 'wandb':
         raise NotImplementedError(
-            f'There is no implementation for WandB load_object_store via URI. Please use '
-            'WandBLogger',
-        )
-    elif backend == 'gs':
-        return GCSObjectStore(bucket=bucket_name)
-    elif backend == 'oci':
-        return OCIObjectStore(bucket=bucket_name)
-    elif backend == 'azure':
-        return LibcloudObjectStore(
-            provider='AZURE_BLOBS',
-            container=bucket_name,
-            key_environ='AZURE_ACCOUNT_NAME',
-            secret_environ='AZURE_ACCOUNT_ACCESS_KEY',
+            f'There is no implementation for WandB load_object_store via URI. Please use WandBLogger',
         )
     elif backend == 'dbfs':
         if path.startswith(MLFLOW_DBFS_PATH_PREFIX):
@@ -445,17 +453,21 @@ def maybe_create_object_store_from_uri(uri: str) -> Optional[ObjectStore]:
             # Create the object store for all other ranks
             if dist.get_global_rank() != 0:
                 store = MLFlowObjectStore(path)
-
             return store
         else:
             # validate if the path conforms to the requirements for UC volume paths
             UCObjectStore.validate_path(path)
             return UCObjectStore(path=path)
-    else:
-        raise NotImplementedError(
-            f'There is no implementation for the cloud backend {backend} via URI. Please use '
-            'one of the supported object stores',
-        )
+
+    # Check if backend is registered
+    elif backend in BACKEND_TO_OBJECT_STORE_FACTORY:
+        return BACKEND_TO_OBJECT_STORE_FACTORY[backend](bucket_name, path)
+
+    # If backend is unknown, raise NotImplementedError
+    raise NotImplementedError(
+        f'There is no implementation for the cloud backend {backend} via URI. Please use '
+        'one of the supported object stores',
+    )
 
 
 def maybe_create_remote_uploader_downloader_from_uri(