Fixing consul with multiple health checks per service (#1994)

* plugins/input/consul: moved check_id from regular fields to tags.

When service has more than one check sending data for both would overwrite each other
resulting only in one check being written (the last one). Adding check_id as a tag
ensures we will get info for all unique checks per service.

* plugins/inputs/consul: updated tests

plugins/inputs/consul/README.md

@@ -29,9 +29,9 @@ to query the data. It will not report the [telemetry](https://www.consul.io/docs
 Tags:
 - node: on which node check/service is registered on
 - service_name: name of the service (this is the service name not the service ID)
+- check_id
 
 Fields:
-- check_id
 - check_name
 - service_id
 - status
@@ -41,6 +41,6 @@ Fields:
 ```
 $ telegraf --config ./telegraf.conf -input-filter consul -test
 * Plugin: consul, Collection 1
-> consul_health_checks,host=wolfpit,node=consul-server-node check_id="serfHealth",check_name="Serf Health Status",service_id="",status="passing" 1464698464486439902
-> consul_health_checks,host=wolfpit,node=consul-server-node,service_name=www.example.com check_id="service:www-example-com.test01",check_name="Service 'www.example.com' check",service_id="www-example-com.test01",status="critical" 1464698464486519036
+> consul_health_checks,host=wolfpit,node=consul-server-node,check_id="serfHealth" check_name="Serf Health Status",service_id="",status="passing" 1464698464486439902
+> consul_health_checks,host=wolfpit,node=consul-server-node,service_name=www.example.com,check_id="service:www-example-com.test01" check_name="Service 'www.example.com' check",service_id="www-example-com.test01",status="critical" 1464698464486519036
 ```

plugins/inputs/consul/consul.go

@@ -95,13 +95,13 @@ func (c *Consul) GatherHealthCheck(acc telegraf.Accumulator, checks []*api.Healt
 		record := make(map[string]interface{})
 		tags := make(map[string]string)
 
-		record["check_id"] = check.CheckID
 		record["check_name"] = check.Name
 		record["service_id"] = check.ServiceID
 		record["status"] = check.Status
 
 		tags["node"] = check.Node
 		tags["service_name"] = check.ServiceName
+		tags["check_id"] = check.CheckID
 
 		acc.AddFields("consul_health_checks", record, tags)
 	}

plugins/inputs/consul/consul_test.go

@@ -22,7 +22,6 @@ var sampleChecks = []*api.HealthCheck{
 
 func TestGatherHealtCheck(t *testing.T) {
 	expectedFields := map[string]interface{}{
-		"check_id":   "foo.health123",
 		"check_name": "foo.health",
 		"status":     "passing",
 		"service_id": "foo.123",
@@ -31,6 +30,7 @@ func TestGatherHealtCheck(t *testing.T) {
 	expectedTags := map[string]string{
 		"node":         "localhost",
 		"service_name": "foo",
+		"check_id":     "foo.health123",
 	}
 
 	var acc testutil.Accumulator