Fix bug 564
[osm/N2VC.git] / n2vc / vnf.py
index d6c87dc..2830571 100644 (file)
@@ -1,11 +1,13 @@
-
+import asyncio
 import logging
 import os
 import os.path
 import re
+import shlex
 import ssl
+import subprocess
 import sys
-import time
+import time
 
 # FIXME: this should load the juju inside or modules without having to
 # explicitly install it. Check why it's not working.
@@ -16,8 +18,8 @@ if path not in sys.path:
     sys.path.insert(1, path)
 
 from juju.controller import Controller
-from juju.model import Model, ModelObserver
-
+from juju.model import ModelObserver
+from juju.errors import JujuAPIError, JujuError
 
 # We might need this to connect to the websocket securely, but test and verify.
 try:
@@ -41,6 +43,10 @@ class N2VCPrimitiveExecutionFailed(Exception):
     """Something failed while attempting to execute a primitive."""
 
 
+class NetworkServiceDoesNotExist(Exception):
+    """The Network Service being acted against does not exist."""
+
+
 # Quiet the debug logging
 logging.getLogger('websockets.protocol').setLevel(logging.INFO)
 logging.getLogger('juju.client.connection').setLevel(logging.WARN)
@@ -83,23 +89,18 @@ class VCAMonitor(ModelObserver):
                 application_name = delta.data['application']
 
                 callback = self.applications[application_name]['callback']
-                callback_args = self.applications[application_name]['callback_args']
+                callback_args = \
+                    self.applications[application_name]['callback_args']
 
                 if old and new:
-                    old_status = old.workload_status
-                    new_status = new.workload_status
-
-                    if old_status == new_status:
-                        """The workload status may fluctuate around certain events,
-                        so wait until the status has stabilized before triggering
-                        the callback."""
-                        if callback:
-                            callback(
-                                self.ns_name,
-                                delta.data['application'],
-                                new_status,
-                                new.workload_status_message,
-                                *callback_args)
+                    # Fire off a callback with the application state
+                    if callback:
+                        callback(
+                            self.ns_name,
+                            delta.data['application'],
+                            new.workload_status,
+                            new.workload_status_message,
+                            *callback_args)
 
                 if old and not new:
                     # This is a charm being removed
@@ -111,7 +112,8 @@ class VCAMonitor(ModelObserver):
                             "",
                             *callback_args)
             except Exception as e:
-                self.log.debug("[1] notify_callback exception {}".format(e))
+                self.log.debug("[1] notify_callback exception: {}".format(e))
+
         elif delta.entity == "action":
             # TODO: Decide how we want to notify the user of actions
 
@@ -138,33 +140,14 @@ class VCAMonitor(ModelObserver):
 
 
 class N2VC:
-
-    # Juju API
-    api = None
-    log = None
-    controller = None
-    connecting = False
-    authenticated = False
-
-    models = {}
-    default_model = None
-
-    # Model Observers
-    monitors = {}
-
-    # VCA config
-    hostname = ""
-    port = 17070
-    username = ""
-    secret = ""
-
     def __init__(self,
                  log=None,
                  server='127.0.0.1',
                  port=17070,
                  user='admin',
                  secret=None,
-                 artifacts=None
+                 artifacts=None,
+                 loop=None,
                  ):
         """Initialize N2VC
 
@@ -181,9 +164,32 @@ class N2VC:
             'port': 17070,
             'artifacts': '/path/to/charms'
         })
-
         """
 
+        # Initialize instance-level variables
+        self.api = None
+        self.log = None
+        self.controller = None
+        self.connecting = False
+        self.authenticated = False
+
+        # For debugging
+        self.refcount = {
+            'controller': 0,
+            'model': 0,
+        }
+
+        self.models = {}
+
+        # Model Observers
+        self.monitors = {}
+
+        # VCA config
+        self.hostname = ""
+        self.port = 17070
+        self.username = ""
+        self.secret = ""
+
         if log:
             self.log = log
         else:
@@ -210,45 +216,130 @@ class N2VC:
 
         self.artifacts = artifacts
 
+        self.loop = loop or asyncio.get_event_loop()
+
     def __del__(self):
         """Close any open connections."""
         yield self.logout()
 
-    def notify_callback(self, model_name, application_name, status, message, callback=None, *callback_args):
+    def notify_callback(self, model_name, application_name, status, message,
+                        callback=None, *callback_args):
         try:
             if callback:
-                callback(model_name, application_name, status, message, *callback_args)
+                callback(
+                    model_name,
+                    application_name,
+                    status, message,
+                    *callback_args,
+                )
         except Exception as e:
             self.log.error("[0] notify_callback exception {}".format(e))
             raise e
         return True
 
     # Public methods
-    async def CreateNetworkService(self, nsd):
-        """Create a new model to encapsulate this network service.
+    async def Relate(self, model_name, vnfd):
+        """Create a relation between the charm-enabled VDUs in a VNF.
 
-        Create a new model in the Juju controller to encapsulate the
-        charms associated with a network service.
+        The Relation mapping has two parts: the id of the vdu owning the endpoint, and the name of the endpoint.
 
-        You can pass either the nsd record or the id of the network
-        service, but this method will fail without one of them.
-        """
-        if not self.authenticated:
-            await self.login()
+        vdu:
+            ...
+            relation:
+            -   provides: dataVM:db
+                requires: mgmtVM:app
 
-        # Ideally, we will create a unique model per network service.
-        # This change will require all components, i.e., LCM and SO, to use
-        # N2VC for 100% compatibility. If we adopt unique models for the LCM,
-        # services deployed via LCM would't be manageable via SO and vice versa
+        This tells N2VC that the charm referred to by the dataVM vdu offers a relation named 'db', and the mgmtVM vdu has an 'app' endpoint that should be connected to a database.
 
-        return self.default_model
+        :param str ns_name: The name of the network service.
+        :param dict vnfd: The parsed yaml VNF descriptor.
+        """
 
-    async def DeployCharms(self, model_name, application_name, vnfd, charm_path, params={}, machine_spec={}, callback=None, *callback_args):
+        # Currently, the call to Relate() is made automatically after the
+        # deployment of each charm; if the relation depends on a charm that
+        # hasn't been deployed yet, the call will fail silently. This will
+        # prevent an API breakage, with the intent of making this an explicitly
+        # required call in a more object-oriented refactor of the N2VC API.
+
+        configs = []
+        vnf_config = vnfd.get("vnf-configuration")
+        if vnf_config:
+            juju = vnf_config['juju']
+            if juju:
+                configs.append(vnf_config)
+
+        for vdu in vnfd['vdu']:
+            vdu_config = vdu.get('vdu-configuration')
+            if vdu_config:
+                juju = vdu_config['juju']
+                if juju:
+                    configs.append(vdu_config)
+
+        def _get_application_name(name):
+            """Get the application name that's mapped to a vnf/vdu."""
+            vnf_member_index = 0
+            vnf_name = vnfd['name']
+
+            for vdu in vnfd.get('vdu'):
+                # Compare the named portion of the relation to the vdu's id
+                if vdu['id'] == name:
+                    application_name = self.FormatApplicationName(
+                        model_name,
+                        vnf_name,
+                        str(vnf_member_index),
+                    )
+                    return application_name
+                else:
+                    vnf_member_index += 1
+
+            return None
+
+        # Loop through relations
+        for cfg in configs:
+            if 'juju' in cfg:
+                if 'relation' in juju:
+                    for rel in juju['relation']:
+                        try:
+
+                            # get the application name for the provides
+                            (name, endpoint) = rel['provides'].split(':')
+                            application_name = _get_application_name(name)
+
+                            provides = "{}:{}".format(
+                                application_name,
+                                endpoint
+                            )
+
+                            # get the application name for thr requires
+                            (name, endpoint) = rel['requires'].split(':')
+                            application_name = _get_application_name(name)
+
+                            requires = "{}:{}".format(
+                                application_name,
+                                endpoint
+                            )
+                            self.log.debug("Relation: {} <-> {}".format(
+                                provides,
+                                requires
+                            ))
+                            await self.add_relation(
+                                model_name,
+                                provides,
+                                requires,
+                            )
+                        except Exception as e:
+                            self.log.debug("Exception: {}".format(e))
+
+        return
+
+    async def DeployCharms(self, model_name, application_name, vnfd,
+                           charm_path, params={}, machine_spec={},
+                           callback=None, *callback_args):
         """Deploy one or more charms associated with a VNF.
 
         Deploy the charm(s) referenced in a VNF Descriptor.
 
-        :param str model_name: The name of the network service.
+        :param str model_name: The name or unique id of the network service.
         :param str application_name: The name of the application
         :param dict vnfd: The name of the application
         :param str charm_path: The path to the Juju charm
@@ -258,15 +349,19 @@ class N2VC:
             'rw_mgmt_ip': '1.2.3.4',
             # Pass the initial-config-primitives section of the vnf or vdu
             'initial-config-primitives': {...}
+            'user_values': dictionary with the day-1 parameters provided at instantiation time. It will replace values
+                inside < >. rw_mgmt_ip will be included here also
           }
-        :param dict machine_spec: A dictionary describing the machine to install to
+        :param dict machine_spec: A dictionary describing the machine to
+        install to
           Examples::
           {
             'hostname': '1.2.3.4',
             'username': 'ubuntu',
           }
         :param obj callback: A callback function to receive status changes.
-        :param tuple callback_args: A list of arguments to be passed to the callback
+        :param tuple callback_args: A list of arguments to be passed to the
+        callback
         """
 
         ########################################################
@@ -274,7 +369,13 @@ class N2VC:
         ########################################################
         if not os.path.exists(charm_path):
             self.log.debug("Charm path doesn't exist: {}".format(charm_path))
-            self.notify_callback(model_name, application_name, "failed", callback, *callback_args)
+            self.notify_callback(
+                model_name,
+                application_name,
+                "failed",
+                callback,
+                *callback_args,
+            )
             raise JujuCharmNotFound("No artifacts configured.")
 
         ################################
@@ -287,9 +388,6 @@ class N2VC:
         ##########################################
         # Get the model for this network service #
         ##########################################
-        # TODO: In a point release, we will use a model per deployed network
-        # service. In the meantime, we will always use the 'default' model.
-        model_name = 'default'
         model = await self.get_model(model_name)
 
         ########################################
@@ -314,15 +412,14 @@ class N2VC:
         ########################################################
         to = ""
         if machine_spec.keys():
-            # TODO: This needs to be tested.
-            # if all(k in machine_spec for k in ['hostname', 'username']):
-            #     # Enlist the existing machine in Juju
-            #     machine = await self.model.add_machine(spec='ssh:%@%'.format(
-            #         specs['host'],
-            #         specs['user'],
-            #     ))
-            #     to = machine.id
-            pass
+            if all(k in machine_spec for k in ['host', 'user']):
+                # Enlist an existing machine as a Juju unit
+                machine = await model.add_machine(spec='ssh:{}@{}:{}'.format(
+                    machine_spec['user'],
+                    machine_spec['host'],
+                    self.GetPrivateKeyPath(),
+                ))
+                to = machine.id
 
         #######################################
         # Get the initial charm configuration #
@@ -332,12 +429,16 @@ class N2VC:
         if 'rw_mgmt_ip' in params:
             rw_mgmt_ip = params['rw_mgmt_ip']
 
+        if 'initial-config-primitive' not in params:
+            params['initial-config-primitive'] = {}
+
         initial_config = self._get_config_from_dict(
             params['initial-config-primitive'],
             {'<rw_mgmt_ip>': rw_mgmt_ip}
         )
 
-        self.log.debug("JujuApi: Deploying charm ({}) from {}".format(
+        self.log.debug("JujuApi: Deploying charm ({}/{}) from {}".format(
+            model_name,
             application_name,
             charm_path,
             to=to,
@@ -357,62 +458,250 @@ class N2VC:
             series='xenial',
             # Apply the initial 'config' primitive during deployment
             config=initial_config,
-            # TBD: Where to deploy the charm to.
-            to=None,
+            # Where to deploy the charm to.
+            to=to,
         )
 
+        # Map the vdu id<->app name,
+        #
+        await self.Relate(model_name, vnfd)
+
         # #######################################
         # # Execute initial config primitive(s) #
         # #######################################
+        uuids = await self.ExecuteInitialPrimitives(
+            model_name,
+            application_name,
+            params,
+        )
+        return uuids
+
+        # primitives = {}
+        #
+        # # Build a sequential list of the primitives to execute
+        # for primitive in params['initial-config-primitive']:
+        #     try:
+        #         if primitive['name'] == 'config':
+        #             # This is applied when the Application is deployed
+        #             pass
+        #         else:
+        #             seq = primitive['seq']
+        #
+        #             params = {}
+        #             if 'parameter' in primitive:
+        #                 params = primitive['parameter']
+        #
+        #             primitives[seq] = {
+        #                 'name': primitive['name'],
+        #                 'parameters': self._map_primitive_parameters(
+        #                     params,
+        #                     {'<rw_mgmt_ip>': rw_mgmt_ip}
+        #                 ),
+        #             }
+        #
+        #             for primitive in sorted(primitives):
+        #                 await self.ExecutePrimitive(
+        #                     model_name,
+        #                     application_name,
+        #                     primitives[primitive]['name'],
+        #                     callback,
+        #                     callback_args,
+        #                     **primitives[primitive]['parameters'],
+        #                 )
+        #     except N2VCPrimitiveExecutionFailed as e:
+        #         self.log.debug(
+        #             "[N2VC] Exception executing primitive: {}".format(e)
+        #         )
+        #         raise
+
+    async def GetPrimitiveStatus(self, model_name, uuid):
+        """Get the status of an executed Primitive.
+
+        The status of an executed Primitive will be one of three values:
+        - completed
+        - failed
+        - running
+        """
+        status = None
+        try:
+            if not self.authenticated:
+                await self.login()
+
+            model = await self.get_model(model_name)
+
+            results = await model.get_action_status(uuid)
+
+            if uuid in results:
+                status = results[uuid]
+
+        except Exception as e:
+            self.log.debug(
+                "Caught exception while getting primitive status: {}".format(e)
+            )
+            raise N2VCPrimitiveExecutionFailed(e)
+
+        return status
+
+    async def GetPrimitiveOutput(self, model_name, uuid):
+        """Get the output of an executed Primitive.
+
+        Note: this only returns output for a successfully executed primitive.
+        """
+        results = None
+        try:
+            if not self.authenticated:
+                await self.login()
+
+            model = await self.get_model(model_name)
+            results = await model.get_action_output(uuid, 60)
+        except Exception as e:
+            self.log.debug(
+                "Caught exception while getting primitive status: {}".format(e)
+            )
+            raise N2VCPrimitiveExecutionFailed(e)
+
+        return results
+
+    # async def ProvisionMachine(self, model_name, hostname, username):
+    #     """Provision machine for usage with Juju.
+    #
+    #     Provisions a previously instantiated machine for use with Juju.
+    #     """
+    #     try:
+    #         if not self.authenticated:
+    #             await self.login()
+    #
+    #         # FIXME: This is hard-coded until model-per-ns is added
+    #         model_name = 'default'
+    #
+    #         model = await self.get_model(model_name)
+    #         model.add_machine(spec={})
+    #
+    #         machine = await model.add_machine(spec='ssh:{}@{}:{}'.format(
+    #             "ubuntu",
+    #             host['address'],
+    #             private_key_path,
+    #         ))
+    #         return machine.id
+    #
+    #     except Exception as e:
+    #         self.log.debug(
+    #             "Caught exception while getting primitive status: {}".format(e)
+    #         )
+    #         raise N2VCPrimitiveExecutionFailed(e)
+
+    def GetPrivateKeyPath(self):
+        homedir = os.environ['HOME']
+        sshdir = "{}/.ssh".format(homedir)
+        private_key_path = "{}/id_n2vc_rsa".format(sshdir)
+        return private_key_path
+
+    async def GetPublicKey(self):
+        """Get the N2VC SSH public key.abs
+
+        Returns the SSH public key, to be injected into virtual machines to
+        be managed by the VCA.
+
+        The first time this is run, a ssh keypair will be created. The public
+        key is injected into a VM so that we can provision the machine with
+        Juju, after which Juju will communicate with the VM directly via the
+        juju agent.
+        """
+        public_key = ""
+
+        # Find the path to where we expect our key to live.
+        homedir = os.environ['HOME']
+        sshdir = "{}/.ssh".format(homedir)
+        if not os.path.exists(sshdir):
+            os.mkdir(sshdir)
+
+        private_key_path = "{}/id_n2vc_rsa".format(sshdir)
+        public_key_path = "{}.pub".format(private_key_path)
+
+        # If we don't have a key generated, generate it.
+        if not os.path.exists(private_key_path):
+            cmd = "ssh-keygen -t {} -b {} -N '' -f {}".format(
+                "rsa",
+                "4096",
+                private_key_path
+            )
+            subprocess.check_output(shlex.split(cmd))
+
+        # Read the public key
+        with open(public_key_path, "r") as f:
+            public_key = f.readline()
+
+        return public_key
+
+    async def ExecuteInitialPrimitives(self, model_name, application_name,
+                                       params, callback=None, *callback_args):
+        """Execute multiple primitives.
+
+        Execute multiple primitives as declared in initial-config-primitive.
+        This is useful in cases where the primitives initially failed -- for
+        example, if the charm is a proxy but the proxy hasn't been configured
+        yet.
+        """
+        uuids = []
         primitives = {}
 
         # Build a sequential list of the primitives to execute
         for primitive in params['initial-config-primitive']:
             try:
                 if primitive['name'] == 'config':
-                    # This is applied when the Application is deployed
                     pass
                 else:
                     seq = primitive['seq']
 
-                    params = {}
+                    params_ = {}
                     if 'parameter' in primitive:
-                        params = primitive['parameter']
+                        params_ = primitive['parameter']
+
+                    user_values = params.get("user_values", {})
+                    if 'rw_mgmt_ip' not in user_values:
+                        user_values['rw_mgmt_ip'] = None
+                        # just for backward compatibility, because it will be provided always by modern version of LCM
 
                     primitives[seq] = {
                         'name': primitive['name'],
                         'parameters': self._map_primitive_parameters(
-                            params,
-                            {'<rw_mgmt_ip>': rw_mgmt_ip}
+                            params_,
+                            user_values
                         ),
                     }
 
                     for primitive in sorted(primitives):
-                        await self.ExecutePrimitive(
-                            model_name,
-                            application_name,
-                            primitives[primitive]['name'],
-                            callback,
-                            callback_args,
-                            **primitives[primitive]['parameters'],
+                        uuids.append(
+                            await self.ExecutePrimitive(
+                                model_name,
+                                application_name,
+                                primitives[primitive]['name'],
+                                callback,
+                                callback_args,
+                                **primitives[primitive]['parameters'],
+                            )
                         )
             except N2VCPrimitiveExecutionFailed as e:
-                self.debug.log(
+                self.log.debug(
                     "[N2VC] Exception executing primitive: {}".format(e)
                 )
                 raise
+        return uuids
 
-    async def ExecutePrimitive(self, model_name, application_name, primitive, callback, *callback_args, **params):
+    async def ExecutePrimitive(self, model_name, application_name, primitive,
+                               callback, *callback_args, **params):
         """Execute a primitive of a charm for Day 1 or Day 2 configuration.
 
         Execute a primitive defined in the VNF descriptor.
 
-        :param str model_name: The name of the network service.
+        :param str model_name: The name or unique id of the network service.
         :param str application_name: The name of the application
         :param str primitive: The name of the primitive to execute.
         :param obj callback: A callback function to receive status changes.
-        :param tuple callback_args: A list of arguments to be passed to the callback function.
-        :param dict params: A dictionary of key=value pairs representing the primitive's parameters
+        :param tuple callback_args: A list of arguments to be passed to the
+         callback function.
+        :param dict params: A dictionary of key=value pairs representing the
+         primitive's parameters
           Examples::
           {
             'rw_mgmt_ip': '1.2.3.4',
@@ -420,37 +709,38 @@ class N2VC:
             'initial-config-primitives': {...}
           }
         """
+        self.log.debug("Executing primitive={} params={}".format(primitive, params))
         uuid = None
         try:
             if not self.authenticated:
                 await self.login()
 
-            # FIXME: This is hard-coded until model-per-ns is added
-            model_name = 'default'
-
-            model = await self.controller.get_model(model_name)
+            model = await self.get_model(model_name)
 
             if primitive == 'config':
                 # config is special, and expecting params to be a dictionary
-                self.log.debug("Setting charm configuration for {}".format(application_name))
-                self.log.debug(params['params'])
-                await self.set_config(model, application_name, params['params'])
+                await self.set_config(
+                    model,
+                    application_name,
+                    params['params'],
+                )
             else:
                 app = await self.get_application(model, application_name)
                 if app:
                     # Run against the first (and probably only) unit in the app
                     unit = app.units[0]
                     if unit:
-                        self.log.debug("Executing primitive {}".format(primitive))
                         action = await unit.run_action(primitive, **params)
                         uuid = action.id
-                await model.disconnect()
         except Exception as e:
-            self.log.debug("Caught exception while executing primitive: {}".format(e))
-            raise e
+            self.log.debug(
+                "Caught exception while executing primitive: {}".format(e)
+            )
+            raise N2VCPrimitiveExecutionFailed(e)
         return uuid
 
-    async def RemoveCharms(self, model_name, application_name, callback=None, *callback_args):
+    async def RemoveCharms(self, model_name, application_name, callback=None,
+                           *callback_args):
         """Remove a charm from the VCA.
 
         Remove a charm referenced in a VNF Descriptor.
@@ -458,7 +748,8 @@ class N2VC:
         :param str model_name: The name of the network service.
         :param str application_name: The name of the application
         :param obj callback: A callback function to receive status changes.
-        :param tuple callback_args: A list of arguments to be passed to the callback function.
+        :param tuple callback_args: A list of arguments to be passed to the
+         callback function.
         """
         try:
             if not self.authenticated:
@@ -471,24 +762,87 @@ class N2VC:
                 self.monitors[model_name].RemoveApplication(application_name)
 
                 # self.notify_callback(model_name, application_name, "removing", callback, *callback_args)
-                self.log.debug("Removing the application {}".format(application_name))
+                self.log.debug(
+                    "Removing the application {}".format(application_name)
+                )
                 await app.remove()
 
-                # Notify the callback that this charm has been removed.
-                self.notify_callback(model_name, application_name, "removed", callback, *callback_args)
+                await self.disconnect_model(self.monitors[model_name])
+
+                self.notify_callback(
+                    model_name,
+                    application_name,
+                    "removed",
+                    "Removing charm {}".format(application_name),
+                    callback,
+                    *callback_args,
+                )
 
         except Exception as e:
             print("Caught exception: {}".format(e))
             self.log.debug(e)
             raise e
 
-    async def DestroyNetworkService(self, nsd):
-        raise NotImplementedError()
+    async def CreateNetworkService(self, ns_uuid):
+        """Create a new Juju model for the Network Service.
+
+        Creates a new Model in the Juju Controller.
+
+        :param str ns_uuid: A unique id representing an instaance of a
+            Network Service.
+
+        :returns: True if the model was created. Raises JujuError on failure.
+        """
+        if not self.authenticated:
+            await self.login()
+
+        models = await self.controller.list_models()
+        if ns_uuid not in models:
+            try:
+                self.models[ns_uuid] = await self.controller.add_model(
+                    ns_uuid
+                )
+            except JujuError as e:
+                if "already exists" not in e.message:
+                    raise e
+        return True
+
+    async def DestroyNetworkService(self, ns_uuid):
+        """Destroy a Network Service.
+
+        Destroy the Network Service and any deployed charms.
+
+        :param ns_uuid The unique id of the Network Service
+
+        :returns: True if the model was created. Raises JujuError on failure.
+        """
+
+        # Do not delete the default model. The default model was used by all
+        # Network Services, prior to the implementation of a model per NS.
+        if ns_uuid.lower() == "default":
+            return False
+
+        if not self.authenticated:
+            self.log.debug("Authenticating with Juju")
+            await self.login()
+
+        # Disconnect from the Model
+        if ns_uuid in self.models:
+            await self.disconnect_model(self.models[ns_uuid])
+
+        try:
+            await self.controller.destroy_models(ns_uuid)
+        except JujuError:
+            raise NetworkServiceDoesNotExist(
+                "The Network Service '{}' does not exist".format(ns_uuid)
+            )
+
+        return True
 
     async def GetMetrics(self, model_name, application_name):
         """Get the metrics collected by the VCA.
 
-        :param model_name The name of the model
+        :param model_name The name or unique id of the network service
         :param application_name The name of the application
         """
         metrics = {}
@@ -499,24 +853,39 @@ class N2VC:
 
         return metrics
 
+    async def HasApplication(self, model_name, application_name):
+        model = await self.get_model(model_name)
+        app = await self.get_application(model, application_name)
+        if app:
+            return True
+        return False
+
     # Non-public methods
-    async def add_relation(self, a, b, via=None):
+    async def add_relation(self, model_name, relation1, relation2):
         """
         Add a relation between two application endpoints.
 
-        :param a An application endpoint
-        :param b An application endpoint
-        :param via The egress subnet(s) for outbound traffic, e.g.,
-            (192.168.0.0/16,10.0.0.0/8)
+        :param str model_name: The name or unique id of the network service
+        :param str relation1: '<application>[:<relation_name>]'
+        :param str relation2: '<application>[:<relation_name>]'
         """
+
         if not self.authenticated:
             await self.login()
 
-        m = await self.get_model()
+        m = await self.get_model(model_name)
         try:
-            m.add_relation(a, b, via)
-        finally:
-            await m.disconnect()
+            await m.add_relation(relation1, relation2)
+        except JujuAPIError as e:
+            # If one of the applications in the relationship doesn't exist,
+            # or the relation has already been added, let the operation fail
+            # silently.
+            if 'not found' in e.message:
+                return
+            if 'already exists' in e.message:
+                return
+
+            raise e
 
     # async def apply_config(self, config, application):
     #     """Apply a configuration to the application."""
@@ -547,14 +916,45 @@ class N2VC:
 
         return config
 
-    def _map_primitive_parameters(self, parameters, values):
+    def _map_primitive_parameters(self, parameters, user_values):
         params = {}
         for parameter in parameters:
             param = str(parameter['name'])
-            if parameter['value'] == "<rw_mgmt_ip>":
-                params[param] = str(values[parameter['value']])
-            else:
-                params[param] = str(parameter['value'])
+            value = parameter.get('value')
+
+            # map parameters inside a < >; e.g. <rw_mgmt_ip>. with the provided user_values.
+            # Must exist at user_values except if there is a default value
+            if isinstance(value, str) and value.startswith("<") and value.endswith(">"):
+                if parameter['value'][1:-1] in user_values:
+                    value = user_values[parameter['value'][1:-1]]
+                elif 'default-value' in parameter:
+                    value = parameter['default-value']
+                else:
+                    raise KeyError("parameter {}='{}' not supplied ".format(param, value))
+
+            # If there's no value, use the default-value (if set)
+            if value is None and 'default-value' in parameter:
+                value = parameter['default-value']
+
+            # Typecast parameter value, if present
+            paramtype = "string"
+            try:
+                if 'data-type' in parameter:
+                    paramtype = str(parameter['data-type']).lower()
+
+                    if paramtype == "integer":
+                        value = int(value)
+                    elif paramtype == "boolean":
+                        value = bool(value)
+                    else:
+                        value = str(value)
+                else:
+                    # If there's no data-type, assume the value is a string
+                    value = str(value)
+            except ValueError:
+                raise ValueError("parameter {}='{}' cannot be converted to type {}".format(param, value, paramtype))
+
+            params[param] = value
         return params
 
     def _get_config_from_yang(self, config_primitive, values):
@@ -586,7 +986,6 @@ class N2VC:
 
             FormatApplicationName("ping_pong_ns", "ping_vnf", "a")
         """
-
         appname = ""
         for c in "-".join(list(args)):
             if c.isdigit():
@@ -594,8 +993,7 @@ class N2VC:
             elif not c.isalpha():
                 c = "-"
             appname += c
-        return re.sub('\-+', '-', appname.lower())
-
+        return re.sub('-+', '-', appname.lower())
 
     # def format_application_name(self, nsd_name, vnfr_name, member_vnf_index=0):
     #     """Format the name of the application
@@ -635,7 +1033,7 @@ class N2VC:
 
         return app
 
-    async def get_model(self, model_name='default'):
+    async def get_model(self, model_name):
         """Get a model from the Juju Controller.
 
         Note: Model objects returned must call disconnected() before it goes
@@ -644,8 +1042,23 @@ class N2VC:
             await self.login()
 
         if model_name not in self.models:
-            print("connecting to model {}".format(model_name))
-            self.models[model_name] = await self.controller.get_model(model_name)
+            # Get the models in the controller
+            models = await self.controller.list_models()
+
+            if model_name not in models:
+                try:
+                    self.models[model_name] = await self.controller.add_model(
+                        model_name
+                    )
+                except JujuError as e:
+                    if "already exists" not in e.message:
+                        raise e
+            else:
+                self.models[model_name] = await self.controller.get_model(
+                    model_name
+                )
+
+            self.refcount['model'] += 1
 
             # Create an observer for this model
             self.monitors[model_name] = VCAMonitor(model_name)
@@ -664,16 +1077,24 @@ class N2VC:
         self.log.debug("JujuApi: Logging into controller")
 
         cacert = None
-        self.controller = Controller()
+        self.controller = Controller(loop=self.loop)
 
         if self.secret:
-            self.log.debug("Connecting to controller... ws://{}:{} as {}/{}".format(self.endpoint, self.port, self.user, self.secret))
+            self.log.debug(
+                "Connecting to controller... ws://{}:{} as {}/{}".format(
+                    self.endpoint,
+                    self.port,
+                    self.user,
+                    self.secret,
+                )
+            )
             await self.controller.connect(
                 endpoint=self.endpoint,
                 username=self.user,
                 password=self.secret,
                 cacert=cacert,
             )
+            self.refcount['controller'] += 1
         else:
             # current_controller no longer exists
             # self.log.debug("Connecting to current controller...")
@@ -688,32 +1109,41 @@ class N2VC:
         self.authenticated = True
         self.log.debug("JujuApi: Logged into controller")
 
-        # self.default_model = await self.controller.get_model("default")
-
     async def logout(self):
         """Logout of the Juju controller."""
         if not self.authenticated:
-            return
+            return False
 
         try:
-            if self.default_model:
-                self.log.debug("Disconnecting model {}".format(self.default_model))
-                await self.default_model.disconnect()
-                self.default_model = None
-
             for model in self.models:
-                await self.models[model].disconnect()
+                await self.disconnect_model(model)
 
             if self.controller:
-                self.log.debug("Disconnecting controller {}".format(self.controller))
+                self.log.debug("Disconnecting controller {}".format(
+                    self.controller
+                ))
                 await self.controller.disconnect()
-                # self.controller = None
+                self.refcount['controller'] -= 1
+                self.controller = None
 
             self.authenticated = False
+
+            self.log.debug(self.refcount)
+
         except Exception as e:
-            self.log.fail("Fatal error logging out of Juju Controller: {}".format(e))
+            self.log.fatal(
+                "Fatal error logging out of Juju Controller: {}".format(e)
+            )
             raise e
+        return True
 
+    async def disconnect_model(self, model):
+        self.log.debug("Disconnecting model {}".format(model))
+        if model in self.models:
+            print("Disconnecting model")
+            await self.models[model].disconnect()
+            self.refcount['model'] -= 1
+            self.models[model] = None
 
     # async def remove_application(self, name):
     #     """Remove the application."""
@@ -744,21 +1174,25 @@ class N2VC:
         finally:
             await m.disconnect()
 
-    async def resolve_error(self, application=None):
+    async def resolve_error(self, model_name, application=None):
         """Resolve units in error state."""
         if not self.authenticated:
             await self.login()
 
-        app = await self.get_application(self.default_model, application)
+        model = await self.get_model(model_name)
+
+        app = await self.get_application(model, application)
         if app:
-            self.log.debug("JujuApi: Resolving errors for application {}".format(
-                application,
-            ))
+            self.log.debug(
+                "JujuApi: Resolving errors for application {}".format(
+                    application,
+                )
+            )
 
             for unit in app.units:
                 app.resolved(retry=True)
 
-    async def run_action(self, application, action_name, **params):
+    async def run_action(self, model_name, application, action_name, **params):
         """Execute an action and return an Action object."""
         if not self.authenticated:
             await self.login()
@@ -769,16 +1203,21 @@ class N2VC:
                 'results': None,
             }
         }
-        app = await self.get_application(self.default_model, application)
+
+        model = await self.get_model(model_name)
+
+        app = await self.get_application(model, application)
         if app:
             # We currently only have one unit per application
             # so use the first unit available.
             unit = app.units[0]
 
-            self.log.debug("JujuApi: Running Action {} against Application {}".format(
-                action_name,
-                application,
-            ))
+            self.log.debug(
+                "JujuApi: Running Action {} against Application {}".format(
+                    action_name,
+                    application,
+                )
+            )
 
             action = await unit.run_action(action_name, **params)
 
@@ -824,25 +1263,28 @@ class N2VC:
     #         application=application,
         # )
 
-    async def wait_for_application(self, name, timeout=300):
+    async def wait_for_application(self, model_name, application_name,
+                                   timeout=300):
         """Wait for an application to become active."""
         if not self.authenticated:
             await self.login()
 
-        app = await self.get_application(self.default_model, name)
+        model = await self.get_model(model_name)
+
+        app = await self.get_application(model, application_name)
+        self.log.debug("Application: {}".format(app))
         if app:
             self.log.debug(
                 "JujuApi: Waiting {} seconds for Application {}".format(
                     timeout,
-                    name,
+                    application_name,
                 )
             )
 
-            await self.default_model.block_until(
+            await model.block_until(
                 lambda: all(
-                    unit.agent_status == 'idle'
-                    and unit.workload_status
-                    in ['active', 'unknown'] for unit in app.units
+                    unit.agent_status == 'idle' and unit.workload_status in
+                    ['active', 'unknown'] for unit in app.units
                 ),
                 timeout=timeout
             )