Use standard reactive flags

Use connected and available to keep separate from joined and changed.

provides.py

@@ -1,4 +1,4 @@
-# Copyright 2017 Canonical Ltd
+# Copyright 2019 Canonical Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -12,18 +12,105 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from charms.reactive import Endpoint
+from charms.reactive import (
+    Endpoint,
+    clear_flag,
+    set_flag,
+    when,
+    when_any,
+)
+
+import uuid
 
 
 class KeystoneFIDServiceProvides(Endpoint):
-    def publish(self, restart_nonce, protocol_name,
-                remote_id_attribute):
+
+    @property
+    def hostname(self):
+        return self.all_joined_units.received['hostname']
+
+    @property
+    def port(self):
+        return self.all_joined_units.received['port']
+
+    @property
+    def tls_enabled(self):
+        return self.all_joined_units.received['tls-enabled']
+
+    @when('endpoint.{endpoint_name}.joined')
+    def joined(self):
+        set_flag(self.expand_name('{endpoint_name}.connected'))
+        self.update_flags()
+
+    @when('endpoint.{endpoint_name}.changed')
+    def changed(self):
+        self.update_flags()
+
+    @when_any('endpoint.{endpoint_name}.broken',
+              'endpoint.{endpoint_name}.departed')
+    def departed(self):
+        flags = (
+            self.expand_name('{endpoint_name}.available'),
+            self.expand_name('{endpoint_name}.connected'),
+        )
+        for flag in flags:
+            clear_flag(flag)
+
+    def data_complete(self):
+        data = {
+            'hostname': self.hostname,
+            'port': self.port,
+            'tls-enabled': self.tls_enabled,
+        }
+        # We only care if the values are None
+        # False is a valid value
+        if all(v is not None for v in data.values()):
+            return True
+        return False
+
+    def update_flags(self):
+        """Update the flags of the relations based on the data that the
+        relation has.
+
+        If the :meth:`data_complete` is False then all of the flags
+        are removed.  Otherwise, the individual flags are set according to
+        their own data methods.
+        """
+        data_complete = self.data_complete()
+        flags = {
+            self.expand_name('{endpoint_name}.available'):
+                self.data_complete(),
+        }
+        for k, v in flags.items():
+            if data_complete and v:
+                set_flag(k)
+            else:
+                clear_flag(k)
+
+    def publish(self, protocol_name, remote_id_attribute):
         # get the first relation object as we only have one relation
         # to a primary as a subordinate
         rel = self.relations[0]
         # can have multiple dashboard charms in general, therefore,
         # all relation objects and all units must be handled
         # to_publish/relation_set work on a per-relation basis
-        rel.to_publish['restart-nonce'] = restart_nonce
         rel.to_publish['protocol-name'] = protocol_name
         rel.to_publish['remote-id-attribute'] = remote_id_attribute
+
+    def request_restart(self, service_type=None):
+        """Request a restart of a set of remote services
+        :param service_type: string Service types to be restarted eg 'neutron'.
+                                    If ommitted a request to restart all
+                                    services is sent
+        """
+        if service_type:
+            key = 'restart-nonce-{}'.format(service_type)
+        else:
+            key = 'restart-nonce'
+        # get the first relation object as we only have one relation
+        # to a primary as a subordinate
+        rel = self.relations[0]
+        # can have multiple dashboard charms in general, therefore,
+        # all relation objects and all units must be handled
+        # to_publish/relation_set work on a per-relation basis
+        rel.to_publish[key] = str(uuid.uuid4())