Change Require to unit scope + bug fixes

* Remove logic for getting rndc info from interface. How the rndc
  secret is derived is not really a function of the  interface, so
  remove it.

* Move slave_ips to use reactive framework rather than dropping down
  to relation_* tools

* Switch to unit scope. Switch interface to UNIT scope so information
  can be collected from individual units.

* Add method for collecting unit and address information

Change-Id: Id9ddb8b6bce8044da160672988492415689616b4

provides.py

@@ -36,16 +36,7 @@ class BindRNDCProvides(RelationBase):
         conv = self.conversation()
         conv.remove_state('{relation_name}.related')
 
-    def send_rndckey_info(self):
-        key_file = '/etc/bind/rndc.key'
-        with open(key_file, 'r') as f:
-            content = f.readlines()
-        # XXX Naive parsing of keyfile
-        for line in content:
-            if line and line.split()[0] == 'algorithm':
-                algorithm = line.split()[1]
-            if line and line.split()[0] == 'secret':
-                rndckey = line.split()[1]
+    def send_rndckey_info(self, rndckey, algorithm):
         for conv in self.conversations():
             conv.set_remote('rndckey', rndckey)
             conv.set_remote('algorithm', algorithm)

requires.py

@@ -6,7 +6,7 @@
 # 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
+#     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,
@@ -20,37 +20,88 @@ from charms.reactive import scopes
 
 
 class BindRNDCRequires(RelationBase):
-    scope = scopes.GLOBAL
+    scope = scopes.UNIT
 
     # These remote data fields will be automatically mapped to accessors
     # with a basic documentation string provided.
-    auto_accessors = ['algorithm', 'rndckey', 'private-address']
 
     @hook('{requires:bind-rndc}-relation-joined')
     def joined(self):
-        self.set_state('{relation_name}.connected')
+        conv = self.conversation()
+        conv.set_state('{relation_name}.connected')
 
     @hook('{requires:bind-rndc}-relation-changed')
     def changed(self):
-        self.set_state('{relation_name}.connected')
+        conv = self.conversation()
+        conv.set_state('{relation_name}.connected')
         if self.data_complete():
-            self.set_state('{relation_name}.available')
+            conv.set_state('{relation_name}.available')
 
     @hook('{requires:bind-rndc}-relation-{broken,departed}')
     def departed_or_broken(self):
-        self.remove_state('{relation_name}.connected')
+        conv = self.conversation()
+        conv.remove_state('{relation_name}.connected')
         if not self.data_complete():
-            self.remove_state('{relation_name}.available')
+            conv.remove_state('{relation_name}.available')
 
     def data_complete(self):
+        """Check if all information for a RNDC connection has been sent
+
+        @returns boolean: True if all required data for connection is present
         """
-        Get the connection string, if available, or None.
-        """
-        data = {
-            'algorithm': self.algorithm(),
-            'secret': self.rndckey(),
-            'private_address': self.private_address(),
-        }
-        if all(data.values()):
+        if self.rndc_info and all(self.rndc_info.values()):
             return True
         return False
+
+    @property
+    def rndc_info(self):
+        """Get RNDC connection information from DNS Slave
+
+        @returns dict: Return dict of RNDC connection information
+        """
+        for conv in self.conversations():
+            data = {
+                'algorithm': conv.get_remote('algorithm'),
+                'secret': conv.get_remote('rndckey'),
+            }
+            if all(data.values()):
+                return data
+        return {}
+
+    @property
+    def algorithm(self):
+        """Get algorith used to gen rndc secret from DNS Slave
+
+        @returns str: Return algorith used to gen rndc secret
+        """
+        return self.rndc_info.get('algorithm')
+
+    @property
+    def rndckey(self):
+        """Get rndc secret from DNS Slave
+
+        @returns str: Return rndc secret
+        """
+        return self.rndc_info.get('secret')
+
+    @property
+    def private_address(self):
+        """Get private address of unit in current relation context
+
+        @returns str: Return ip address
+        """
+        conv = self.conversation()
+        return conv.get_remote('private-address')
+
+    def slave_ips(self):
+        """Address information of DNS slaves
+
+        @return list: List of dicts containing unit name and address
+        """
+        values = []
+        for conv in self.conversations():
+            values.append({
+                # Unit scoped relation so only one unit per conversation.
+                'unit': list(conv.units)[0],
+                'address': conv.get_remote('private-address')})
+        return values