Merge pull request #16 from petevg/bug/keyerror-in-is-leader

[osm/N2VC.git] / juju / unit.py

diff --git a/juju/unit.py b/juju/unit.py
index 3dbc1e9..2ec1769 100644 (file)
--- a/juju/unit.py
+++ b/juju/unit.py
@@ -1,4 +1,3 @@
-import asyncio
 import logging
 from datetime import datetime
 
@@ -57,6 +56,10 @@ class Unit(model.ModelEntity):
         """
         return self.data['workload-status']['message']
 
+    @property
+    def tag(self):
+        return 'unit-%s' % self.name.replace('/', '-')
+
     def add_storage(self, name, constraints=None):
         """Add unit storage dynamically.
 
@@ -128,14 +131,39 @@ class Unit(model.ModelEntity):
         )
         return await self.model.wait_for_action(res.results[0].action.tag)
 
-    def run_action(self, action_name, **params):
-        """Run action on this unit.
+    async def run_action(self, action_name, **params):
+        """Run an action on this unit.
 
         :param str action_name: Name of action to run
         :param \*\*params: Action parameters
-
-        """
-        pass
+        :returns: An `juju.action.Action` instance.
+
+        Note that this only enqueues the action.  You will need to call
+        ``action.wait()`` on the resulting `Action` instance if you wish
+        to block until the action is complete.
+        """
+        action_facade = client.ActionFacade()
+        action_facade.connect(self.connection)
+
+        log.debug('Starting action `%s` on %s', action_name, self.name)
+
+        res = await action_facade.Enqueue([client.Action(
+            name=action_name,
+            parameters=params,
+            receiver=self.tag,
+        )])
+        action = res.results[0].action
+        error = res.results[0].error
+        if error and error.code == 'not found':
+            raise ValueError('Action `%s` not found on %s' % (action_name,
+                                                              self.name))
+        elif error:
+            raise Exception('Unknown action error: %s' % error.serialize())
+        action_id = action.tag[len('action-'):]
+        log.debug('Action started as %s', action_id)
+        # we mustn't use wait_for_action because that blocks until the
+        # action is complete, rather than just being in the model
+        return await self.model._wait_for_new('action', action_id)
 
     def scp(
             self, source_path, user=None, destination_path=None, proxy=False,
@@ -178,3 +206,35 @@ class Unit(model.ModelEntity):
 
         """
         pass
+
+    async def is_leader_from_status(self):
+        """
+        Check to see if this unit is the leader. Returns True if so, and
+        False if it is not, or if leadership does not make sense
+        (e.g., there is no leader in this application.)
+
+        This method is a kluge that calls FullStatus in the
+        ClientFacade to get its information. Once
+        https://bugs.launchpad.net/juju/+bug/1643691 is resolved, we
+        should add a simple .is_leader property, and deprecate this
+        method.
+
+        """
+        app = self.name.split("/")[0]
+
+        c = client.ClientFacade()
+        c.connect(self.model.connection)
+
+        status = await c.FullStatus(None)
+
+        try:
+            return status.applications[app]['units'][self.name].get(
+                'leader', False)
+        except KeyError:
+            # FullStatus may be more up-to-date than the model
+            # referenced by this class. If this unit has been
+            # destroyed between the time the class was created and the
+            # time that we call this method, we'll get a KeyError. In
+            # that case, we simply return False, as a destroyed unit
+            # is not a leader.
+            return False