Add tags option to datadog telemetry

Expose an global tags option in telemetry config for dogstatsd, for
purposes of distinguishing between multiple nomad cluster metrics.

command/agent/command.go

@@ -748,6 +748,7 @@ func (c *Command) setupTelemetry(config *Config) (*metrics.InmemSink, error) {
 		if err != nil {
 			return inm, err
 		}
+		sink.SetTags(telConfig.DataDogTags)
 		fanout = append(fanout, sink)
 	}
 

command/agent/config.go

@@ -355,6 +355,7 @@ type Telemetry struct {
 	StatsiteAddr             string        `mapstructure:"statsite_address"`
 	StatsdAddr               string        `mapstructure:"statsd_address"`
 	DataDogAddr              string        `mapstructure:"datadog_address"`
+	DataDogTags              []string      `mapstructure:"datadog_tags"`
 	PrometheusMetrics        bool          `mapstructure:"prometheus_metrics"`
 	DisableHostname          bool          `mapstructure:"disable_hostname"`
 	UseNodeName              bool          `mapstructure:"use_node_name"`
@@ -1170,6 +1171,9 @@ func (a *Telemetry) Merge(b *Telemetry) *Telemetry {
 	if b.DataDogAddr != "" {
 		result.DataDogAddr = b.DataDogAddr
 	}
+	if b.DataDogTags != nil {
+		result.DataDogTags = b.DataDogTags
+	}
 	if b.PrometheusMetrics {
 		result.PrometheusMetrics = b.PrometheusMetrics
 	}

command/agent/config_parse.go

@@ -641,6 +641,7 @@ func parseTelemetry(result **Telemetry, list *ast.ObjectList) error {
 		"publish_allocation_metrics",
 		"publish_node_metrics",
 		"datadog_address",
+		"datadog_tags",
 		"prometheus_metrics",
 		"circonus_api_token",
 		"circonus_api_app",

command/agent/config_test.go

@@ -56,6 +56,7 @@ func TestConfig_Merge(t *testing.T) {
 			StatsiteAddr:                       "127.0.0.1:8125",
 			StatsdAddr:                         "127.0.0.1:8125",
 			DataDogAddr:                        "127.0.0.1:8125",
+			DataDogTags:                        []string{"cat1:tag1", "cat2:tag2"},
 			PrometheusMetrics:                  true,
 			DisableHostname:                    false,
 			DisableTaggedMetrics:               true,
@@ -191,6 +192,7 @@ func TestConfig_Merge(t *testing.T) {
 			StatsiteAddr:                       "127.0.0.2:8125",
 			StatsdAddr:                         "127.0.0.2:8125",
 			DataDogAddr:                        "127.0.0.1:8125",
+			DataDogTags:                        []string{"cat1:tag1", "cat2:tag2"},
 			PrometheusMetrics:                  true,
 			DisableHostname:                    true,
 			PublishNodeMetrics:                 true,

website/source/api/agent.html.md

@@ -279,6 +279,7 @@ $ curl \
       "CirconusSubmissionInterval": "",
       "CollectionInterval": "1s",
       "DataDogAddr": "",
+      "DataDogTags": [],
       "DisableHostname": false,
       "PublishAllocationMetrics": false,
       "PublishNodeMetrics": false,

website/source/docs/agent/configuration/telemetry.html.md

@@ -108,9 +108,15 @@ These `telemetry` parameters apply to
 - `datadog_address` `(string: "")` - Specifies the address of a DataDog statsd
   server to forward metrics to.
 
+- `datadog_tags` `(list: [])` - Specifies a list of global tags that will be
+  added to all telemetry packets sent to DogStatsD. It is a list of strings,
+  where each string looks like "my_tag_name:my_tag_value".
+
+
 ```hcl
 telemetry {
   datadog_address = "dogstatsd.company.local:8125"
+  datadog_tags = ["my_tag_name:my_tag_value"]
 }
 ```