Make is_leader tag optional (#3114)

etcd/datadog_checks/etcd/data/conf.yaml.example

@@ -11,6 +11,11 @@ instances:
   #
   #  prometheus_url: http://localhost:2379/metrics
 
+  ## @param leader_tag - boolean - optional - default: true
+  ## Whether or not to tag with `is_leader:true` or `is_leader:false`.
+  #
+  #  leader_tag: true
+
   ## @param send_histograms_buckets - boolean - optional - default: true
   ## Histogram buckets can be noisy and generate many tags.
   ## Set send_histograms_buckets to true to pull them.

etcd/datadog_checks/etcd/etcd.py

@@ -168,7 +168,9 @@ def check_post_v3(self, instance):
             )
 
         tags = []
-        self.add_leader_state_tag(scraper_config, tags)
+
+        if is_affirmative(instance.get('leader_tag', True)):
+            self.add_leader_state_tag(scraper_config, tags)
 
         scraper_config['_metric_tags'][:] = tags
 

etcd/tests/test_etcd.py

@@ -1,6 +1,8 @@
 # (C) Datadog, Inc. 2018
 # All rights reserved
 # Licensed under a 3-clause BSD style license (see LICENSE)
+from copy import deepcopy
+
 import pytest
 import requests
 from six import itervalues
@@ -52,6 +54,23 @@ def test_check(aggregator, instance):
     assert aggregator.metrics_asserted_pct > 80
 
 
+@preview
+def test_check_no_leader_tag(aggregator, instance):
+    instance = deepcopy(instance)
+    instance['leader_tag'] = False
+
+    check = Etcd('etcd', {}, {}, [instance])
+    check.check(instance)
+
+    for metric in itervalues(METRIC_MAP):
+        try:
+            aggregator.assert_metric(metric, tags=[])
+        except AssertionError:
+            pass
+
+    assert aggregator.metrics_asserted_pct > 80
+
+
 @preview
 def test_service_check(aggregator, instance):
     check = Etcd(CHECK_NAME, None, {}, [instance])