1 files changed, 154 insertions, 0 deletions
diff --git a/azure/aria/aria-extension-cloudify/src/aria/aria/extension.py b/azure/aria/aria-extension-cloudify/src/aria/aria/extension.py
new file mode 100644
index 0000000..e90750d
--- /dev/null
+++ b/azure/aria/aria-extension-cloudify/src/aria/aria/extension.py
@@ -0,0 +1,154 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+
+"""
+Mechanism for registering and loading ARIA extensions.
+"""
+
+# pylint: disable=no-self-use
+
+from .utils import collections
+
+
+class _Registrar(object):
+
+    def __init__(self, registry):
+        if not isinstance(registry, (dict, list)):
+            raise RuntimeError('Unsupported registry type')
+        self._registry = registry
+
+    def register(self, function):
+        result = function()
+        if isinstance(self._registry, dict):
+            for key in result:
+                if key in self._registry:
+                    raise RuntimeError('Re-definition of {0} in {1}'.format(key, function.__name__))
+            self._registry.update(result)
+        elif isinstance(self._registry, list):
+            if not isinstance(result, (list, tuple, set)):
+                result = [result]
+            self._registry += list(result)
+        else:
+            raise RuntimeError('Illegal state')
+
+    def __call__(self):
+        return self._registry
+
+
+def _registrar(function):
+    function._registrar_function = True
+    return function
+
+
+class _ExtensionRegistration(object):
+    """
+    Base class for extension class decorators.
+    """
+
+    def __init__(self):
+        self._registrars = {}
+        self._registered_classes = []
+        for attr, value in vars(self.__class__).items():
+            try:
+                is_registrar_function = value._registrar_function
+            except AttributeError:
+                is_registrar_function = False
+            if is_registrar_function:
+                registrar = _Registrar(registry=getattr(self, attr)())
+                setattr(self, attr, registrar)
+                self._registrars[attr] = registrar
+
+    def __call__(self, cls):
+        self._registered_classes.append(cls)
+        return cls
+
+    def init(self):
+        """
+        Initialize all registrars by calling all registered functions.
+        """
+        registered_instances = [cls() for cls in self._registered_classes]
+        for name, registrar in self._registrars.items():
+            for instance in registered_instances:
+                registrating_function = getattr(instance, name, None)
+                if registrating_function:
+                    registrar.register(registrating_function)
+
+
+class _ParserExtensionRegistration(_ExtensionRegistration):
+    """
+    Parser extensions class decorator.
+    """
+
+    @_registrar
+    def presenter_class(self):
+        """
+        Presentation class registration.
+
+        Implementing functions can return a single class or a list/tuple of classes.
+        """
+        return []
+
+    @_registrar
+    def specification_package(self):
+        """
+        Specification package registration.
+
+        Implementing functions can return a package name or a list/tuple of names.
+        """
+        return []
+
+    @_registrar
+    def specification_url(self):
+        """
+        Specification URL registration.
+
+        Implementing functions should return a dictionary from names to URLs.
+        """
+        return {}
+
+    @_registrar
+    def uri_loader_prefix(self):
+        """
+        URI loader prefix registration.
+
+        Implementing functions can return a single prefix or a list/tuple of prefixes.
+        """
+        return collections.StrictList(value_class=basestring)
+
+parser = _ParserExtensionRegistration()
+
+
+class _ProcessExecutorExtensionRegistration(_ExtensionRegistration):
+    """
+    Process executor extension class decorator.
+    """
+
+    @_registrar
+    def decorate(self):
+        """
+        The operation function executed by the process executor will be decorated with the function
+        returned from ``decorate()``.
+        """
+        return []
+
+process_executor = _ProcessExecutorExtensionRegistration()
+
+
+def init():
+    """
+    Initialize all registrars by calling all registered functions.
+    """
+    parser.init()
+    process_executor.init()