Make 'os-hosts/node1' case sensitivity defer to DB

RPC is case sensitive, but URL is not, and DB can be. So pull host_name from DB
in HostAPI RPC layer instead of from passed in from URL.  This means RPC will
always get the proper capitalization, and case sensitivity is defined in DB layer.

Fix bug 996879

Change-Id: I448dd4ec3aec4af1adf4487f26ea996db572fa3d

nova/compute/api.py

@@ -2480,31 +2480,33 @@ def __init__(self, rpcapi=None):
 
     def _assert_host_exists(self, context, host_name):
         """Raise HostNotFound if compute host doesn't exist."""
-        if not self.db.service_get_by_host_and_topic(context, host_name,
-                                                     CONF.compute_topic):
+        service = self.db.service_get_by_host_and_topic(context, host_name,
+                CONF.compute_topic)
+        if not service:
             raise exception.HostNotFound(host=host_name)
+        return service['host']
 
     def set_host_enabled(self, context, host_name, enabled):
         """Sets the specified host's ability to accept new instances."""
-        self._assert_host_exists(context, host_name)
+        host_name = self._assert_host_exists(context, host_name)
         return self.rpcapi.set_host_enabled(context, enabled=enabled,
                 host=host_name)
 
     def get_host_uptime(self, context, host_name):
         """Returns the result of calling "uptime" on the target host."""
-        self._assert_host_exists(context, host_name)
+        host_name = self._assert_host_exists(context, host_name)
         return self.rpcapi.get_host_uptime(context, host=host_name)
 
     def host_power_action(self, context, host_name, action):
         """Reboots, shuts down or powers up the host."""
-        self._assert_host_exists(context, host_name)
+        host_name = self._assert_host_exists(context, host_name)
         return self.rpcapi.host_power_action(context, action=action,
                 host=host_name)
 
     def set_host_maintenance(self, context, host_name, mode):
         """Start/Stop host maintenance window. On start, it triggers
         guest VMs evacuation."""
-        self._assert_host_exists(context, host_name)
+        host_name = self._assert_host_exists(context, host_name)
         return self.rpcapi.host_maintenance_mode(context,
                 host_param=host_name, mode=mode, host=host_name)
 

nova/tests/compute/test_host_api.py

@@ -38,8 +38,10 @@ def _mock_assert_host_exists(self):
         """Sets it so that the host API always thinks that 'fake_host'
         exists.
         """
-        self.mox.StubOutWithMock(self.host_api, '_assert_host_exists')
-        self.host_api._assert_host_exists(self.ctxt, 'fake_host')
+        def fake_assert_host_exists(context, host_name):
+            return 'fake_host'
+        self.stubs.Set(self.host_api, '_assert_host_exists',
+                                    fake_assert_host_exists)
 
     def test_set_host_enabled(self):
         self._mock_assert_host_exists()
@@ -53,6 +55,18 @@ def test_set_host_enabled(self):
                                                 'fake_enabled')
         self.assertEqual('fake-result', result)
 
+    def test_host_name_from_assert_hosts_exists(self):
+        self._mock_assert_host_exists()
+        self._mock_rpc_call(
+                {'method': 'set_host_enabled',
+                 'args': {'enabled': 'fake_enabled'},
+                 'version': compute_rpcapi.ComputeAPI.BASE_RPC_API_VERSION})
+
+        self.mox.ReplayAll()
+        result = self.host_api.set_host_enabled(self.ctxt, 'fake_hosT',
+                                                'fake_enabled')
+        self.assertEqual('fake-result', result)
+
     def test_get_host_uptime(self):
         self._mock_assert_host_exists()
         self._mock_rpc_call(