Switch to setuptools entrypoint based backend registeration

CHANGELOG.rst

@@ -6,6 +6,7 @@ Current
 
 - Added backend level configuration ``FS_{BACKEND_NAME}_{KEY}``
 - Improved backend documentation
+- Use setuptools entry points to register backends.
 
 0.3.0 (2017-03-05)
 ------------------

docs/backends.rst

@@ -52,6 +52,16 @@ Custom backends
 Flask-FS allows you to defined your own backend
 by extending the :class:`~flask_fs.backends.BaseBackend` class.
 
+You need to register your backend using setuptools entrypoints in your ``setup.py``:
+
+.. code-block:: python
+
+    entry_points={
+        'fs.backend': [
+            'custom = my.custom.package:CustomBackend',
+        ]
+    },
+
 
 Sample configuration
 --------------------

flask_fs/__init__.py

@@ -8,7 +8,7 @@
 try:
     from flask import current_app
 
-    from .backends import BaseBackend, DEFAULT_BACKEND, BUILTIN_BACKENDS  # noqa: Facade pattern
+    from .backends import BaseBackend, DEFAULT_BACKEND  # noqa: Facade pattern
     from .errors import *  # noqa: Facade pattern
     from .files import *  # noqa: Facade pattern
     from .storage import Storage  # noqa: Facade pattern
@@ -36,7 +36,7 @@ def init_app(app, *storages):
     app.config.setdefault('FS_ROOT', join(app.instance_path, 'fs'))
     app.config.setdefault('FS_PREFIX', None)
     app.config.setdefault('FS_URL', None)
-    app.config.setdefault('FS_BACKEND', 'local')
+    app.config.setdefault('FS_BACKEND', DEFAULT_BACKEND)
     app.config.setdefault('FS_IMAGES_OPTIMIZE', False)
 
     state = app.extensions['fs'] = app.extensions.get('fs', {})

flask_fs/backends/__init__.py

@@ -3,16 +3,9 @@
 
 import six
 
-__all__ = [i.encode('ascii') for i in ('BaseBackend', 'DEFAULT_BACKEND', 'BUILTIN_BACKENDS')]
+__all__ = [i.encode('ascii') for i in ('BaseBackend', 'DEFAULT_BACKEND')]
 
 
-BUILTIN_BACKENDS = {
-    'local': 'flask_fs.backends.local.LocalBackend',
-    's3': 'flask_fs.backends.s3.S3Backend',
-    'swift': 'flask_fs.backends.swift.SwiftBackend',
-    'grids': 'flask_fs.backends.gridfs.GridFsBackend',
-}
-
 DEFAULT_BACKEND = 'local'
 
 

flask_fs/backends/mock.py

@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import logging
+
+from . import BaseBackend
+
+log = logging.getLogger(__name__)
+
+
+class MockBackend(BaseBackend):
+    '''
+    A backend with only purpose of being mocked
+    '''
+    pass

flask_fs/storage.py

@@ -1,19 +1,13 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 
+import pkg_resources
 import os.path
 
-try:
-    from urllib.parse import urljoin
-except:
-    from urlparse import urljoin
-
 from flask import current_app, url_for, request, abort
+from six.moves.urllib.parse import urljoin
 from werkzeug import secure_filename, FileStorage, cached_property
-from werkzeug.utils import import_string
-
 
-from .backends import BUILTIN_BACKENDS
 from .errors import UnauthorizedFileType, FileExists, OperationNotSupported, FileNotFound
 from .files import DEFAULTS, extension, lower_extension
 
@@ -30,6 +24,9 @@
 # Config keys that should be overwritten from backend config
 BACKEND_EXCLUDED_CONFIG = ('BACKEND', 'URL', 'ROOT')
 
+# Load registered backends
+BACKENDS = dict((ep.name, ep) for ep in pkg_resources.iter_entry_points('fs.backend'))
+
 
 class Config(dict):
     '''
@@ -120,10 +117,10 @@ def configure(self, app):
             if key.startswith(prefix):
                 config[key.replace(prefix, '').lower()] = value
 
-        if self.backend_name in BUILTIN_BACKENDS:
-            backend_class = import_string(BUILTIN_BACKENDS[self.backend_name])
-        else:
-            backend_class = import_string(self.backend_name)
+        if self.backend_name not in BACKENDS:
+            raise ValueError('Unknown backend "{0}"'.format(self.backend_name))
+        backend_class = BACKENDS[self.backend_name].load()
+        backend_class.backend_name = self.backend_name
         self.backend = backend_class(self.name, config)
         self.config = config
 

requirements/test.pip

@@ -1,10 +1,10 @@
 -r s3.pip
 -r gridfs.pip
 -r swift.pip
-mock
 pytest
 pytest-faker
 pytest-flask
 pytest-sugar
+pytest-mock
 flask-mongoengine
 pillow

setup.py

@@ -68,6 +68,15 @@ def pip(filename):
         'ci': ci_require,
         'dev': dev_require,
     },
+    entry_points={
+        'fs.backend': [
+            'local = flask_fs.backends.local:LocalBackend',
+            's3 = flask_fs.backends.s3:S3Backend [s3]',
+            'gridfs = flask_fs.backends.gridfs:GridFsBackend [gridfs]',
+            'swift = flask_fs.backends.swift:SwiftBackend [swift]',
+            'mock = flask_fs.backends.mock:MockBackend',
+        ]
+    },
     license='MIT',
     use_2to3=True,
     zip_safe=False,

tests/conftest.py

@@ -4,13 +4,10 @@
 import io
 import os
 import six
-import mock
 
 from flask import Flask
 from werkzeug.datastructures import FileStorage
 
-import flask_fs as fs
-
 import pytest
 
 BIN_FILE = os.path.join(os.path.dirname(__file__), 'flask.png')
@@ -61,15 +58,8 @@ def utils(faker):
     return Utils()
 
 
-class MockBackend(fs.BaseBackend):
-    pass
-
-
-MOCK_BACKEND = '.'.join((__name__, MockBackend.__name__))
-
-
 @pytest.fixture
-def mock_backend(app):
-    app.config['FS_BACKEND'] = MOCK_BACKEND
-    patcher = mock.patch(MOCK_BACKEND)
-    yield patcher.start()
+def mock_backend(app, mocker):
+    app.config['FS_BACKEND'] = 'mock'
+    mock = mocker.patch('flask_fs.backends.mock.MockBackend')
+    yield mock