diff --git a/modules/libjuju/juju/controller.py b/modules/libjuju/juju/controller.py
index 55ea55e..957ab85 100644
--- a/modules/libjuju/juju/controller.py
+++ b/modules/libjuju/juju/controller.py
@@ -1,69 +1,101 @@
 import asyncio
 import logging
 
-from . import errors
-from . import tag
-from . import utils
-from .client import client
-from .client import connection
-from .model import Model
+from . import errors, tag, utils
+from .client import client, connector
 from .user import User
 
 log = logging.getLogger(__name__)
 
 
-class Controller(object):
-    def __init__(self, loop=None,
-                 max_frame_size=connection.Connection.DEFAULT_FRAME_SIZE):
+class Controller:
+    def __init__(
+        self,
+        loop=None,
+        max_frame_size=None,
+        bakery_client=None,
+        jujudata=None,
+    ):
         """Instantiate a new Controller.
 
         One of the connect_* methods will need to be called before this
         object can be used for anything interesting.
 
+        If jujudata is None, jujudata.FileJujuData will be used.
+
         :param loop: an asyncio event loop
-
+        :param max_frame_size: See
+            `juju.client.connection.Connection.MAX_FRAME_SIZE`
+        :param bakery_client httpbakery.Client: The bakery client to use
+            for macaroon authorization.
+        :param jujudata JujuData: The source for current controller information.
         """
-        self.loop = loop or asyncio.get_event_loop()
-        self.max_frame_size = None
-        self.connection = None
-        self.controller_name = None
+        self._connector = connector.Connector(
+            loop=loop,
+            max_frame_size=max_frame_size,
+            bakery_client=bakery_client,
+            jujudata=jujudata,
+        )
 
-    async def connect(
-            self, endpoint, username, password, cacert=None, macaroons=None):
-        """Connect to an arbitrary Juju controller.
+    async def __aenter__(self):
+        await self.connect()
+        return self
 
+    async def __aexit__(self, exc_type, exc, tb):
+        await self.disconnect()
+
+    @property
+    def loop(self):
+        return self._connector.loop
+
+    async def connect(self, controller_name=None, **kwargs):
+        """Connect to a Juju controller.
+
+        If any arguments are specified other than controller_name,
+        then controller_name must be None and an explicit
+        connection will be made using Connection.connect
+        using those parameters (the 'uuid' parameter must
+        be absent or None).
+
+        Otherwise, if controller_name is None, connect to the
+        current controller.
+
+        Otherwise, controller_name must specify the name
+        of a known controller.
         """
-        self.connection = await connection.Connection.connect(
-            endpoint, None, username, password, cacert, macaroons,
-            max_frame_size=self.max_frame_size)
+        await self.disconnect()
+        if not kwargs:
+            await self._connector.connect_controller(controller_name)
+        else:
+            if controller_name is not None:
+                raise ValueError('controller name may not be specified with other connect parameters')
+            if kwargs.get('uuid') is not None:
+                # A UUID implies a model connection, not a controller connection.
+                raise ValueError('model UUID specified when connecting to controller')
+            await self._connector.connect(**kwargs)
 
-    async def connect_current(self):
-        """Connect to the current Juju controller.
+    async def _connect_direct(self, **kwargs):
+        await self.disconnect()
+        await self._connector.connect(**kwargs)
 
-        """
-        jujudata = connection.JujuData()
-        controller_name = jujudata.current_controller()
-        if not controller_name:
-            raise errors.JujuConnectionError('No current controller')
-        return await self.connect_controller(controller_name)
+    def is_connected(self):
+        """Reports whether the Controller is currently connected."""
+        return self._connector.is_connected()
 
-    async def connect_controller(self, controller_name):
-        """Connect to a Juju controller by name.
+    def connection(self):
+        """Return the current Connection object. It raises an exception
+        if the Controller is disconnected"""
+        return self._connector.connection()
 
-        """
-        self.connection = (
-            await connection.Connection.connect_controller(
-                controller_name, max_frame_size=self.max_frame_size))
-        self.controller_name = controller_name
+    @property
+    def controller_name(self):
+        return self._connector.controller_name
 
     async def disconnect(self):
         """Shut down the watcher task and close websockets.
 
         """
-        if self.connection and self.connection.is_open:
-            log.debug('Closing controller connection')
-            await self.connection.close()
-            self.connection = None
+        await self._connector.disconnect()
 
     async def add_credential(self, name=None, credential=None, cloud=None,
                              owner=None):
@@ -84,20 +116,19 @@
             cloud = await self.get_cloud()
 
         if not owner:
-            owner = self.connection.info['user-info']['identity']
+            owner = self.connection().info['user-info']['identity']
 
         if credential and not name:
             raise errors.JujuError('Name must be provided for credential')
 
         if not credential:
-            name, credential = connection.JujuData().load_credential(cloud,
-                                                                     name)
+            name, credential = self._connector.jujudata.load_credential(cloud, name)
             if credential is None:
-                raise errors.JujuError('Unable to find credential: '
-                                       '{}'.format(name))
+                raise errors.JujuError(
+                    'Unable to find credential: {}'.format(name))
 
         log.debug('Uploading credential %s', name)
-        cloud_facade = client.CloudFacade.from_connection(self.connection)
+        cloud_facade = client.CloudFacade.from_connection(self.connection())
         await cloud_facade.UpdateCredentials([
             client.UpdateCloudCredential(
                 tag=tag.credential(cloud, tag.untag('user-', owner), name),
@@ -121,12 +152,12 @@
             the current user.
         :param dict config: Model configuration.
         :param str region: Region in which to create the model.
-
+        :return Model: A connection to the newly created model.
         """
         model_facade = client.ModelManagerFacade.from_connection(
-            self.connection)
+            self.connection())
 
-        owner = owner or self.connection.info['user-info']['identity']
+        owner = owner or self.connection().info['user-info']['identity']
         cloud_name = cloud_name or await self.get_cloud()
 
         try:
@@ -153,7 +184,7 @@
         if not config or 'authorized-keys' not in config:
             config = config or {}
             config['authorized-keys'] = await utils.read_ssh_key(
-                loop=self.loop)
+                loop=self._connector.loop)
 
         model_info = await model_facade.CreateModel(
             tag.cloud(cloud_name),
@@ -163,17 +194,11 @@
             owner,
             region
         )
-
-        model = Model()
-        await model.connect(
-            self.connection.endpoint,
-            model_info.uuid,
-            self.connection.username,
-            self.connection.password,
-            self.connection.cacert,
-            self.connection.macaroons,
-            loop=self.loop,
-        )
+        from juju.model import Model
+        model = Model(jujudata=self._connector.jujudata)
+        kwargs = self.connection().connect_params()
+        kwargs['uuid'] = model_info.uuid
+        await model._connect_direct(**kwargs)
 
         return model
 
@@ -183,12 +208,12 @@
         :param str \*models: Names or UUIDs of models to destroy
 
         """
-        uuids = await self._model_uuids()
+        uuids = await self.model_uuids()
         models = [uuids[model] if model in uuids else model
                   for model in models]
 
         model_facade = client.ModelManagerFacade.from_connection(
-            self.connection)
+            self.connection())
 
         log.debug(
             'Destroying model%s %s',
@@ -212,7 +237,7 @@
         """
         if not display_name:
             display_name = username
-        user_facade = client.UserManagerFacade.from_connection(self.connection)
+        user_facade = client.UserManagerFacade.from_connection(self.connection())
         users = [client.AddUser(display_name=display_name,
                                 username=username,
                                 password=password)]
@@ -223,7 +248,7 @@
         """Remove a user from this controller.
         """
         client_facade = client.UserManagerFacade.from_connection(
-            self.connection)
+            self.connection())
         user = tag.user(username)
         await client_facade.RemoveUser([client.Entity(user)])
 
@@ -234,7 +259,7 @@
         :param str password: New password
 
         """
-        user_facade = client.UserManagerFacade.from_connection(self.connection)
+        user_facade = client.UserManagerFacade.from_connection(self.connection())
         entity = client.EntityPassword(password, tag.user(username))
         return await user_facade.SetPassword([entity])
 
@@ -246,7 +271,7 @@
 
         """
         controller_facade = client.ControllerFacade.from_connection(
-            self.connection)
+            self.connection())
         return await controller_facade.DestroyController(destroy_all_models)
 
     async def disable_user(self, username):
@@ -255,7 +280,7 @@
         :param str username: Username
 
         """
-        user_facade = client.UserManagerFacade.from_connection(self.connection)
+        user_facade = client.UserManagerFacade.from_connection(self.connection())
         entity = client.Entity(tag.user(username))
         return await user_facade.DisableUser([entity])
 
@@ -263,7 +288,7 @@
         """Re-enable a previously disabled user.
 
         """
-        user_facade = client.UserManagerFacade.from_connection(self.connection)
+        user_facade = client.UserManagerFacade.from_connection(self.connection())
         entity = client.Entity(tag.user(username))
         return await user_facade.EnableUser([entity])
 
@@ -278,17 +303,35 @@
         """
         Get the name of the cloud that this controller lives on.
         """
-        cloud_facade = client.CloudFacade.from_connection(self.connection)
+        cloud_facade = client.CloudFacade.from_connection(self.connection())
 
         result = await cloud_facade.Clouds()
         cloud = list(result.clouds.keys())[0]  # only lives on one cloud
         return tag.untag('cloud-', cloud)
 
-    async def _model_uuids(self, all_=False, username=None):
+    async def get_models(self, all_=False, username=None):
+        """
+        .. deprecated:: 0.7.0
+           Use :meth:`.list_models` instead.
+        """
         controller_facade = client.ControllerFacade.from_connection(
             self.connection)
         for attempt in (1, 2, 3):
             try:
+                return await controller_facade.AllModels()
+            except errors.JujuAPIError as e:
+                # retry concurrency error until resolved in Juju
+                # see: https://bugs.launchpad.net/juju/+bug/1721786
+                if 'has been removed' not in e.message or attempt == 3:
+                    raise
+
+    async def model_uuids(self):
+        """Return a mapping of model names to UUIDs.
+        """
+        controller_facade = client.ControllerFacade.from_connection(
+            self.connection())
+        for attempt in (1, 2, 3):
+            try:
                 response = await controller_facade.AllModels()
                 return {um.model.name: um.model.uuid
                         for um in response.user_models}
@@ -297,17 +340,14 @@
                 # see: https://bugs.launchpad.net/juju/+bug/1721786
                 if 'has been removed' not in e.message or attempt == 3:
                     raise
-                await asyncio.sleep(attempt, loop=self.loop)
+                await asyncio.sleep(attempt, loop=self._connector.loop)
 
-    async def list_models(self, all_=False, username=None):
+    async def list_models(self):
         """Return list of names of the available models on this controller.
 
-        :param bool all_: List all models, regardless of user accessibilty
-            (admin use only)
-        :param str username: User for which to list models (admin use only)
-
+        Equivalent to ``sorted((await self.model_uuids()).keys())``
         """
-        uuids = await self._model_uuids(all_, username)
+        uuids = await self.model_uuids()
         return sorted(uuids.keys())
 
     def get_payloads(self, *patterns):
@@ -347,24 +387,19 @@
         """Get a model by name or UUID.
 
         :param str model: Model name or UUID
-
+        :returns Model: Connected Model instance.
         """
-        uuids = await self._model_uuids()
+        uuids = await self.model_uuids()
         if model in uuids:
-            name_or_uuid = uuids[model]
+            uuid = uuids[model]
         else:
-            name_or_uuid = model
+            uuid = model
 
+        from juju.model import Model
         model = Model()
-        await model.connect(
-            self.connection.endpoint,
-            name_or_uuid,
-            self.connection.username,
-            self.connection.password,
-            self.connection.cacert,
-            self.connection.macaroons,
-            loop=self.loop,
-        )
+        kwargs = self.connection().connect_params()
+        kwargs['uuid'] = uuid
+        await model._connect_direct(**kwargs)
         return model
 
     async def get_user(self, username):
@@ -374,7 +409,7 @@
         :returns: A :class:`~juju.user.User` instance
         """
         client_facade = client.UserManagerFacade.from_connection(
-            self.connection)
+            self.connection())
         user = tag.user(username)
         args = [client.Entity(user)]
         try:
@@ -396,32 +431,77 @@
         :returns: A list of :class:`~juju.user.User` instances
         """
         client_facade = client.UserManagerFacade.from_connection(
-            self.connection)
+            self.connection())
         response = await client_facade.UserInfo(None, include_disabled)
         return [User(self, r.result) for r in response.results]
 
     async def grant(self, username, acl='login'):
-        """Set access level of the given user on the controller
-
+        """Grant access level of the given user on the controller.
+        Note that if the user already has higher permissions than the
+        provided ACL, this will do nothing (see revoke for a way to
+        remove permissions).
         :param str username: Username
         :param str acl: Access control ('login', 'add-model' or 'superuser')
-
+        :returns: True if new access was granted, False if user already had
+            requested access or greater.  Raises JujuError if failed.
         """
         controller_facade = client.ControllerFacade.from_connection(
-            self.connection)
+            self.connection())
         user = tag.user(username)
-        await self.revoke(username)
         changes = client.ModifyControllerAccess(acl, 'grant', user)
-        return await controller_facade.ModifyControllerAccess([changes])
+        try:
+            await controller_facade.ModifyControllerAccess([changes])
+            return True
+        except errors.JujuError as e:
+            if 'user already has' in str(e):
+                return False
+            else:
+                raise
 
-    async def revoke(self, username):
-        """Removes all access from a controller
+    async def revoke(self, username, acl='login'):
+        """Removes some or all access of a user to from a controller
+        If 'login' access is revoked, the user will no longer have any
+        permissions on the controller. Revoking a higher privilege from
+        a user without that privilege will have no effect.
 
         :param str username: username
-
+        :param str acl: Access to remove ('login', 'add-model' or 'superuser')
         """
         controller_facade = client.ControllerFacade.from_connection(
-            self.connection)
+            self.connection())
         user = tag.user(username)
         changes = client.ModifyControllerAccess('login', 'revoke', user)
         return await controller_facade.ModifyControllerAccess([changes])
+
+    async def grant_model(self, username, model_uuid, acl='read'):
+        """Grant a user access to a model. Note that if the user
+        already has higher permissions than the provided ACL,
+        this will do nothing (see revoke_model for a way to remove permissions).
+
+        :param str username: Username
+        :param str model_uuid: The UUID of the model to change.
+        :param str acl: Access control ('read, 'write' or 'admin')
+        """
+        model_facade = client.ModelManagerFacade.from_connection(
+            self.connection())
+        user = tag.user(username)
+        model = tag.model(model_uuid)
+        changes = client.ModifyModelAccess(acl, 'grant', model, user)
+        return await model_facade.ModifyModelAccess([changes])
+
+    async def revoke_model(self, username, model_uuid, acl='read'):
+        """Revoke some or all of a user's access to a model.
+        If 'read' access is revoked, the user will no longer have any
+        permissions on the model. Revoking a higher privilege from
+        a user without that privilege will have no effect.
+
+        :param str username: Username to revoke
+        :param str model_uuid: The UUID of the model to change.
+        :param str acl: Access control ('read, 'write' or 'admin')
+        """
+        model_facade = client.ModelManagerFacade.from_connection(
+            self.connection())
+        user = tag.user(username)
+        model = tag.model(self.info.uuid)
+        changes = client.ModifyModelAccess(acl, 'revoke', model, user)
+        return await model_facade.ModifyModelAccess([changes])