Refactor stack output fetching

We are duplicating the code to fetch a specific value from the stack
outputs. This adds a get_stack_output_item that can be used to fetch
any named stack output and refactors the other functions that did this
same type of action.

Change-Id: I9f45661d432c47f9df962009cc3c6b9182006d1c

tripleoclient/tests/test_utils.py

@@ -613,6 +613,36 @@ class TestCreateTempestDeployerInput(TestCase):
                 '[volume-feature-enabled]\nbootable = true', cfg)
 
 
+class TestGetStackOutputItem(TestCase):
+
+    def test_get_stack_output_item(self):
+        stack = mock.MagicMock()
+        emap = {'KeystonePublic': {'uri': 'http://foo:8000/'}}
+        stack.to_dict.return_value = {
+            'outputs': [{'output_key': 'EndpointMap',
+                         'output_value': emap}]
+        }
+
+        endpoint_map = utils.get_stack_output_item(stack, 'EndpointMap')
+        self.assertEqual(endpoint_map,
+                         {'KeystonePublic': {'uri': 'http://foo:8000/'}})
+
+    def test_get_stack_output_item_not_found(self):
+        stack = mock.MagicMock()
+        stack.to_dict.return_value = {
+            'outputs': [{'output_key': 'foo',
+                         'output_value': 'bar'}]
+        }
+
+        val = utils.get_stack_output_item(stack, 'baz')
+        self.assertEqual(val, None)
+
+    def test_get_stack_output_item_no_stack(self):
+        stack = None
+        val = utils.get_stack_output_item(stack, 'baz')
+        self.assertEqual(val, None)
+
+
 class TestGetEndpointMap(TestCase):
 
     def test_get_endpoint_map(self):

tripleoclient/utils.py

@@ -511,10 +511,19 @@ def set_nodes_state(baremetal_client, nodes, transition, target_state,
         yield node.uuid
 
 
-def get_overcloud_endpoint(stack):
+def get_stack_output_item(stack, item):
+    if not stack:
+        return None
+
     for output in stack.to_dict().get('outputs', {}):
-        if output['output_key'] == 'KeystoneURL':
+        if output['output_key'] == item:
             return output['output_value']
+    # item not found in outputs
+    return None
+
+
+def get_overcloud_endpoint(stack):
+    return get_stack_output_item(stack, 'KeystoneURL')
 
 
 def get_service_ips(stack):
@@ -525,24 +534,18 @@ def get_service_ips(stack):
 
 
 def get_endpoint_map(stack):
-    endpoint_map = {}
-    for output in stack.to_dict().get('outputs', {}):
-        if output['output_key'] == 'EndpointMap':
-            endpoint_map = output['output_value']
-            break
+    endpoint_map = get_stack_output_item(stack, 'EndpointMap')
+    if not endpoint_map:
+        endpoint_map = {}
     return endpoint_map
 
 
 def get_blacklisted_ip_addresses(stack):
-    for output in stack.to_dict().get('outputs', {}):
-        if output['output_key'] == 'BlacklistedIpAddresses':
-            return output['output_value']
+    return get_stack_output_item(stack, 'BlacklistedIpAddresses')
 
 
 def get_role_net_ip_map(stack):
-    for output in stack.to_dict().get('outputs', {}):
-        if output['output_key'] == 'RoleNetIpMap':
-            return output['output_value']
+    return get_stack_output_item(stack, 'RoleNetIpMap')
 
 
 def get_endpoint(key, stack):