Initial commit of interface

interfaces.yaml

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+name: openstack-ha
+summary: Interface for peer relation
+maintainer: OpenStack Charmers <openstack-charmers@lists.ubuntu.com>

peers.py

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+#!/usr/bin/python
+# 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 charms.reactive import RelationBase
+from charms.reactive import hook
+from charms.reactive import scopes
+
+class OpenstackHAPeers(RelationBase):
+    scope = scopes.UNIT
+
+    @hook('{peers:openstack-ha}-relation-joined')
+    def joined(self):
+        conv = self.conversation()
+        conv.set_state('{relation_name}.joined')
+
+    @hook('{peers:openstack-ha}-relation-changed')
+    def changed(self):
+        conv = self.conversation()
+        conv.set_state('{relation_name}.connected')
+        if self.data_complete(conv):
+            conv.set_state('{relation_name}.available')
+
+    def ip_map(self, address_key='private-address'):
+        nodes = []
+        for conv in self.conversations():
+            host_name = conv.scope.replace('/', '-')
+            nodes.append((host_name, conv.get_remote(address_key)))
+
+        return nodes
+
+    @hook('{peers:openstack-ha}-relation-{broken,departed}')
+    def departed_or_broken(self):
+        conv = self.conversation()
+        conv.remove_state('{relation_name}.connected')
+        if not self.data_complete(conv):
+            conv.remove_state('{relation_name}.available')
+
+    def data_complete(self, conv):
+        """
+        Get the connection string, if available, or None.
+        """
+        data = {
+            'private_address': conv.get_remote('private-address'),
+        }
+        if all(data.values()):
+            return True
+        return False