use variable for client schemes, allowing override (#467)

* use variable for client schemes, allowing override

This change is intended to make the default client implementations
more flexible so that their scheme can be customized. This can be
useful in scenarios where a subclass wants to implement a custom
scheme on e.g. a S3 compatible API [1] but with a custom scheme
so that the default S3 access is still also available.

[1] https://cloudpathlib.drivendata.org/stable/authentication/#accessing-custom-s3-compatible-object-stores

The tests have been updated to include a new s3-like rig which uses the
new scheme override functionality.

* use single cloud_prefix

* tests: switch to lighter-weight custom scheme tests

* update HISTORY file for custom scheme support

* update custom scheme tests to utilize pytest fixture

This isolates the implementation in response to PR feedback:
#467 (comment)

HISTORY.md

@@ -1,5 +1,9 @@
 # cloudpathlib Changelog
 
+## UNRELEASED
+
+- Added support for custom schemes in CloudPath and Client subclases. (Issue [#466](https://github.com/drivendataorg/cloudpathlib/issues/466), PR [#467](https://github.com/drivendataorg/cloudpathlib/pull/467))
+
 ## v0.19.0 (2024-08-29)
 
 - Fixed an error that occurred when loading and dumping `CloudPath` objects using pickle multiple times. (Issue [#450](https://github.com/drivendataorg/cloudpathlib/issues/450), PR [#454](https://github.com/drivendataorg/cloudpathlib/pull/454), thanks to [@kujenga](https://github.com/kujenga))

cloudpathlib/azure/azblobclient.py

@@ -276,12 +276,14 @@ def _list_dir(
     ) -> Iterable[Tuple[AzureBlobPath, bool]]:
         if not cloud_path.container:
             for container in self.service_client.list_containers():
-                yield self.CloudPath(f"az://{container.name}"), True
+                yield self.CloudPath(f"{cloud_path.cloud_prefix}{container.name}"), True
 
                 if not recursive:
                     continue
 
-                yield from self._list_dir(self.CloudPath(f"az://{container.name}"), recursive=True)
+                yield from self._list_dir(
+                    self.CloudPath(f"{cloud_path.cloud_prefix}{container.name}"), recursive=True
+                )
             return
 
         container_client = self.service_client.get_container_client(cloud_path.container)
@@ -295,7 +297,9 @@ def _list_dir(
             paths = file_system_client.get_paths(path=cloud_path.blob, recursive=recursive)
 
             for path in paths:
-                yield self.CloudPath(f"az://{cloud_path.container}/{path.name}"), path.is_directory
+                yield self.CloudPath(
+                    f"{cloud_path.cloud_prefix}{cloud_path.container}/{path.name}"
+                ), path.is_directory
 
         else:
             if not recursive:
@@ -306,7 +310,9 @@ def _list_dir(
             for blob in blobs:
                 # walk_blobs returns folders with a trailing slash
                 blob_path = blob.name.rstrip("/")
-                blob_cloud_path = self.CloudPath(f"az://{cloud_path.container}/{blob_path}")
+                blob_cloud_path = self.CloudPath(
+                    f"{cloud_path.cloud_prefix}{cloud_path.container}/{blob_path}"
+                )
 
                 yield blob_cloud_path, (
                     isinstance(blob, BlobPrefix)

cloudpathlib/gs/gsclient.py

@@ -183,7 +183,8 @@ def _list_dir(self, cloud_path: GSPath, recursive=False) -> Iterable[Tuple[GSPat
                 )
 
             yield from (
-                (self.CloudPath(f"gs://{str(b)}"), True) for b in self.client.list_buckets()
+                (self.CloudPath(f"{cloud_path.cloud_prefix}{str(b)}"), True)
+                for b in self.client.list_buckets()
             )
             return
 
@@ -200,25 +201,30 @@ def _list_dir(self, cloud_path: GSPath, recursive=False) -> Iterable[Tuple[GSPat
                     # if we haven't surfaced this directory already
                     if parent not in yielded_dirs and str(parent) != ".":
                         yield (
-                            self.CloudPath(f"gs://{cloud_path.bucket}/{prefix}{parent}"),
+                            self.CloudPath(
+                                f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{prefix}{parent}"
+                            ),
                             True,  # is a directory
                         )
                         yielded_dirs.add(parent)
-                yield (self.CloudPath(f"gs://{cloud_path.bucket}/{o.name}"), False)  # is a file
+                yield (
+                    self.CloudPath(f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{o.name}"),
+                    False,
+                )  # is a file
         else:
             iterator = bucket.list_blobs(delimiter="/", prefix=prefix)
 
             # files must be iterated first for `.prefixes` to be populated:
             #   see: https://github.com/googleapis/python-storage/issues/863
             for file in iterator:
                 yield (
-                    self.CloudPath(f"gs://{cloud_path.bucket}/{file.name}"),
+                    self.CloudPath(f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{file.name}"),
                     False,  # is a file
                 )
 
             for directory in iterator.prefixes:
                 yield (
-                    self.CloudPath(f"gs://{cloud_path.bucket}/{directory}"),
+                    self.CloudPath(f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{directory}"),
                     True,  # is a directory
                 )
 

cloudpathlib/s3/s3client.py

@@ -217,7 +217,7 @@ def _list_dir(self, cloud_path: S3Path, recursive=False) -> Iterable[Tuple[S3Pat
                 )
 
             yield from (
-                (self.CloudPath(f"s3://{b['Name']}"), True)
+                (self.CloudPath(f"{cloud_path.cloud_prefix}{b['Name']}"), True)
                 for b in self.client.list_buckets().get("Buckets", [])
             )
             return
@@ -241,7 +241,9 @@ def _list_dir(self, cloud_path: S3Path, recursive=False) -> Iterable[Tuple[S3Pat
                 canonical = result_prefix.get("Prefix").rstrip("/")  # keep a canonical form
                 if canonical not in yielded_dirs:
                     yield (
-                        self.CloudPath(f"s3://{cloud_path.bucket}/{canonical}"),
+                        self.CloudPath(
+                            f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{canonical}"
+                        ),
                         True,
                     )
                     yielded_dirs.add(canonical)
@@ -254,7 +256,9 @@ def _list_dir(self, cloud_path: S3Path, recursive=False) -> Iterable[Tuple[S3Pat
                     parent_canonical = prefix + str(parent).rstrip("/")
                     if parent_canonical not in yielded_dirs and str(parent) != ".":
                         yield (
-                            self.CloudPath(f"s3://{cloud_path.bucket}/{parent_canonical}"),
+                            self.CloudPath(
+                                f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{parent_canonical}"
+                            ),
                             True,
                         )
                         yielded_dirs.add(parent_canonical)
@@ -267,15 +271,19 @@ def _list_dir(self, cloud_path: S3Path, recursive=False) -> Iterable[Tuple[S3Pat
                 # s3 fake directories have 0 size and end with "/"
                 if result_key.get("Key").endswith("/") and result_key.get("Size") == 0:
                     yield (
-                        self.CloudPath(f"s3://{cloud_path.bucket}/{canonical}"),
+                        self.CloudPath(
+                            f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{canonical}"
+                        ),
                         True,
                     )
                     yielded_dirs.add(canonical)
 
                 # yield object as file
                 else:
                     yield (
-                        self.CloudPath(f"s3://{cloud_path.bucket}/{result_key.get('Key')}"),
+                        self.CloudPath(
+                            f"{cloud_path.cloud_prefix}{cloud_path.bucket}/{result_key.get('Key')}"
+                        ),
                         False,
                     )
 

tests/test_client.py

@@ -1,11 +1,16 @@
 import mimetypes
 import os
-from pathlib import Path
 import random
 import string
+from pathlib import Path
+
+import pytest
 
 from cloudpathlib import CloudPath
+from cloudpathlib.client import register_client_class
+from cloudpathlib.cloudpath import implementation_registry, register_path_class
 from cloudpathlib.s3.s3client import S3Client
+from cloudpathlib.s3.s3path import S3Path
 
 
 def test_default_client_instantiation(rig):
@@ -116,3 +121,49 @@ def my_content_type(path):
 
     for suffix, content_type in mimes:
         _test_write_content_type(suffix, content_type, rig)
+
+
+@pytest.fixture
+def custom_s3_path():
+    # A fixture isolates these classes as they modify the global registry of
+    # implementations.
+    @register_path_class("mys3")
+    class MyS3Path(S3Path):
+        cloud_prefix: str = "mys3://"
+
+    @register_client_class("mys3")
+    class MyS3Client(S3Client):
+        pass
+
+    yield (MyS3Path, MyS3Client)
+
+    # cleanup after use
+    implementation_registry.pop("mys3")
+
+
+def test_custom_mys3path_instantiation(custom_s3_path):
+    CustomPath, _ = custom_s3_path
+
+    path = CustomPath("mys3://bucket/dir/file.txt")
+    assert isinstance(path, CustomPath)
+    assert path.cloud_prefix == "mys3://"
+    assert path.bucket == "bucket"
+    assert path.key == "dir/file.txt"
+
+
+def test_custom_mys3client_instantiation(custom_s3_path):
+    _, CustomClient = custom_s3_path
+
+    client = CustomClient()
+    assert isinstance(client, CustomClient)
+    assert client.CloudPath("mys3://bucket/dir/file.txt").cloud_prefix == "mys3://"
+
+
+def test_custom_mys3client_default_client(custom_s3_path):
+    _, CustomClient = custom_s3_path
+
+    CustomClient().set_as_default_client()
+
+    path = CloudPath("mys3://bucket/dir/file.txt")
+    assert isinstance(path.client, CustomClient)
+    assert path.cloud_prefix == "mys3://"