[Feature] Istio Mixer and Mesh endpoints are optional (#3875)

* Make Mesh and Mixer config Optional

istio/README.md

@@ -31,7 +31,7 @@ instances:
     send_histograms_buckets: true
 ```
 
-The first two endpoints are required for the check to work. See the [istio documentation][4] to learn more about the prometheus adapter.
+Each of the endpoints are optional, but at least one must be configured. See the [istio documentation][4] to learn more about the prometheus adapter.
 
 ### Validation
 

istio/datadog_checks/istio/data/conf.yaml.example

@@ -2,7 +2,7 @@ init_config:
 
 instances:
 
-    ## @param istio_mesh_endpoint - string - required
+    ## @param istio_mesh_endpoint - string - optional
     ## To enable Istio metrics you must specify the url exposing the API
     ##
     ## Note for RHEL and SUSE users: due to compatibility issues, the check does not make use of
@@ -11,7 +11,7 @@ instances:
     #
   - istio_mesh_endpoint: http://istio-telemetry.istio-system:42422/metrics
 
-    ## @param mixer_endpoint - string - required
+    ## @param mixer_endpoint - string - optional
     ## Define the mixer endpoint in order to collect all Prometheus metrics on the Mixer process as well
     ## as gRPC metrics related to API calls and metrics on adapter dispatch.
     ## If using Istio < v1.1, replace port 15014 with port 9093. See the changes here:

istio/datadog_checks/istio/istio.py

@@ -27,23 +27,26 @@ def __init__(self, name, init_config, agentConfig, instances=None):
 
     def check(self, instance):
         """
-        Process the istio_mesh endpoint, the process_mixer endpoint and optionally the pilot and galley endpoints
+        Process the istio_mesh, process_mixer, pilot, and galley endpoints
         associated with this instance.
+        All the endpoints themselves are optional, but at least one must be passed.
         """
 
         # Get the config for the istio_mesh instance
         istio_mesh_endpoint = instance.get('istio_mesh_endpoint')
-        istio_mesh_config = self.config_map[istio_mesh_endpoint]
+        if istio_mesh_endpoint:
+            istio_mesh_config = self.config_map[istio_mesh_endpoint]
 
-        # Process istio_mesh
-        self.process(istio_mesh_config)
+            # Process istio_mesh
+            self.process(istio_mesh_config)
 
         # Get the config for the process_mixer instance
         process_mixer_endpoint = instance.get('mixer_endpoint')
-        process_mixer_config = self.config_map[process_mixer_endpoint]
+        if process_mixer_endpoint:
+            process_mixer_config = self.config_map[process_mixer_endpoint]
 
-        # Process process_mixer
-        self.process(process_mixer_config)
+            # Process process_mixer
+            self.process(process_mixer_config)
 
         # Get the config for the process_pilot instance
         process_pilot_endpoint = instance.get('pilot_endpoint')
@@ -61,15 +64,21 @@ def check(self, instance):
             # Process process_galley
             self.process(process_galley_config)
 
+        # Check that at least 1 endpoint is configured
+        if not (process_galley_endpoint or process_pilot_endpoint or process_mixer_endpoint or istio_mesh_endpoint):
+            raise CheckException("At least one of Mixer, Mesh, Pilot, or Galley endpoints must be configured")
+
     def create_generic_instances(self, instances):
         """
         Generalize each (single) Istio instance into two OpenMetricsBaseCheck instances
         """
         for instance in instances:
-            istio_mesh_instance = self._create_istio_mesh_instance(instance)
-            yield istio_mesh_instance
-            process_mixer_instance = self._create_process_mixer_instance(instance)
-            yield process_mixer_instance
+            if 'istio_mesh_endpoint' in instance:
+                istio_mesh_instance = self._create_istio_mesh_instance(instance)
+                yield istio_mesh_instance
+            if 'mixer_endpoint' in instance:
+                process_mixer_instance = self._create_process_mixer_instance(instance)
+                yield process_mixer_instance
             if 'pilot_endpoint' in instance:
                 process_pilot_instance = self._create_process_pilot_instance(instance)
                 yield process_pilot_instance

istio/tests/test_check.py

@@ -368,6 +368,10 @@
     'galley_endpoint': 'http://istio-galley:15014/metrics',
 }
 
+NEW_MOCK_PILOT_ONLY_INSTANCE = {'pilot_endpoint': 'http://istio-pilot:15014/metrics'}
+
+NEW_MOCK_GALLEY_ONLY_INSTANCE = {'galley_endpoint': 'http://istio-galley:15014/metrics'}
+
 
 class MockResponse:
     """
@@ -419,6 +423,32 @@ def new_mesh_mixture_fixture():
         yield
 
 
+@pytest.fixture
+def new_pilot_fixture():
+    files = ['pilot.txt']
+    responses = []
+    for filename in files:
+        file_path = os.path.join(os.path.dirname(__file__), 'fixtures', '1.1', filename)
+        with open(file_path, 'r') as f:
+            responses.append(f.read())
+
+    with mock.patch('requests.get', return_value=MockResponse(responses, 'text/plain'), __name__="get"):
+        yield
+
+
+@pytest.fixture
+def new_galley_fixture():
+    files = ['galley.txt']
+    responses = []
+    for filename in files:
+        file_path = os.path.join(os.path.dirname(__file__), 'fixtures', '1.1', filename)
+        with open(file_path, 'r') as f:
+            responses.append(f.read())
+
+    with mock.patch('requests.get', return_value=MockResponse(responses, 'text/plain'), __name__="get"):
+        yield
+
+
 def test_istio(aggregator, mesh_mixture_fixture):
     """
     Test the full check
@@ -442,6 +472,26 @@ def test_new_istio(aggregator, new_mesh_mixture_fixture):
     aggregator.assert_all_metrics_covered()
 
 
+def test_pilot_only_istio(aggregator, new_pilot_fixture):
+    check = Istio('istio', {}, {}, [NEW_MOCK_PILOT_ONLY_INSTANCE])
+    check.check(NEW_MOCK_PILOT_ONLY_INSTANCE)
+
+    for metric in PILOT_METRICS:
+        aggregator.assert_metric(metric)
+
+    aggregator.assert_all_metrics_covered()
+
+
+def test_galley_only_istio(aggregator, new_galley_fixture):
+    check = Istio('istio', {}, {}, [NEW_MOCK_GALLEY_ONLY_INSTANCE])
+    check.check(NEW_MOCK_GALLEY_ONLY_INSTANCE)
+
+    for metric in GALLEY_METRICS:
+        aggregator.assert_metric(metric)
+
+    aggregator.assert_all_metrics_covered()
+
+
 def test_scraper_creator():
     check = Istio('istio', {}, {}, [MOCK_INSTANCE])
     istio_mesh_config = check.config_map.get(MOCK_INSTANCE['istio_mesh_endpoint'])