vFW and vDNS support added to azure-plugin

[multicloud/azure.git] / azure / aria / aria-extension-cloudify / src / aria / aria / parser / reading / reader.py

diff --git a/azure/aria/aria-extension-cloudify/src/aria/aria/parser/reading/reader.py b/azure/aria/aria-extension-cloudify/src/aria/aria/parser/reading/reader.py
new file mode 100644 (file)
index 0000000..1a29f11
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+++ b/azure/aria/aria-extension-cloudify/src/aria/aria/parser/reading/reader.py
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+# Licensed 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.
+
+from ...utils.openclose import OpenClose
+from .exceptions import ReaderException, AlreadyReadException
+
+
+class Reader(object):
+    """
+    Base class for ARIA readers.
+
+    Readers provide agnostic raw data by consuming :class:`aria.parser.loading.Loader` instances.
+    """
+
+    def __init__(self, context, location, loader):
+        self.context = context
+        self.location = location
+        self.loader = loader
+
+    def load(self):
+        with OpenClose(self.loader) as loader:
+            if self.context is not None:
+                with self.context._locations:
+                    for location in self.context._locations:
+                        if location.is_equivalent(loader.location):
+                            raise AlreadyReadException('already read: %s' % loader.location)
+                    self.context._locations.append(loader.location)
+
+            data = loader.load()
+            if data is None:
+                raise ReaderException('loader did not provide data: %s' % loader)
+            return data
+
+    def read(self):
+        raise NotImplementedError