Add Splunk Metrics serializer (influxdata#4339)

docs/DATA_FORMATS_OUTPUT.md

@@ -7,6 +7,7 @@ plugins.
 1. [InfluxDB Line Protocol](#influx)
 1. [JSON](#json)
 1. [Graphite](#graphite)
+1. [SplunkMetric](../plugins/serializers/splunkmetric/README.md)
 
 You will be able to identify the plugins with support by the presence of a
 `data_format` config option, for example, in the `file` output plugin:

internal/config/config.go

@@ -1693,6 +1693,18 @@ func buildSerializer(name string, tbl *ast.Table) (serializers.Serializer, error
 		}
 	}
 
+	if node, ok := tbl.Fields["splunkmetric_hec_routing"]; ok {
+		if kv, ok := node.(*ast.KeyValue); ok {
+			if b, ok := kv.Value.(*ast.Boolean); ok {
+				var err error
+				c.HecRouting, err = b.Boolean()
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+	}
+
 	delete(tbl.Fields, "influx_max_line_bytes")
 	delete(tbl.Fields, "influx_sort_fields")
 	delete(tbl.Fields, "influx_uint_support")
@@ -1701,6 +1713,7 @@ func buildSerializer(name string, tbl *ast.Table) (serializers.Serializer, error
 	delete(tbl.Fields, "prefix")
 	delete(tbl.Fields, "template")
 	delete(tbl.Fields, "json_timestamp_units")
+	delete(tbl.Fields, "splunkmetric_hec_routing")
 	return serializers.NewSerializer(c)
 }
 

plugins/serializers/registry.go

@@ -9,6 +9,7 @@ import (
 	"github.com/influxdata/telegraf/plugins/serializers/graphite"
 	"github.com/influxdata/telegraf/plugins/serializers/influx"
 	"github.com/influxdata/telegraf/plugins/serializers/json"
+	"github.com/influxdata/telegraf/plugins/serializers/splunkmetric"
 )
 
 // SerializerOutput is an interface for output plugins that are able to
@@ -60,6 +61,9 @@ type Config struct {
 
 	// Timestamp units to use for JSON formatted output
 	TimestampUnits time.Duration
+
+	// Include HEC routing fields for splunkmetric output
+	HecRouting bool
 }
 
 // NewSerializer a Serializer interface based on the given config.
@@ -73,6 +77,8 @@ func NewSerializer(config *Config) (Serializer, error) {
 		serializer, err = NewGraphiteSerializer(config.Prefix, config.Template, config.GraphiteTagSupport)
 	case "json":
 		serializer, err = NewJsonSerializer(config.TimestampUnits)
+	case "splunkmetric":
+		serializer, err = NewSplunkmetricSerializer(config.HecRouting)
 	default:
 		err = fmt.Errorf("Invalid data format: %s", config.DataFormat)
 	}
@@ -83,6 +89,10 @@ func NewJsonSerializer(timestampUnits time.Duration) (Serializer, error) {
 	return json.NewSerializer(timestampUnits)
 }
 
+func NewSplunkmetricSerializer(splunkmetric_hec_routing bool) (Serializer, error) {
+	return splunkmetric.NewSerializer(splunkmetric_hec_routing)
+}
+
 func NewInfluxSerializerConfig(config *Config) (Serializer, error) {
 	var sort influx.FieldSortOrder
 	if config.InfluxSortFields {

plugins/serializers/splunkmetric/README.md

@@ -0,0 +1,139 @@
+# Splunk Metrics serializer
+
+This serializer formats and outputs the metric data in a format that can be consumed by a Splunk metrics index.
+It can be used to write to a file using the file output, or for sending metrics to a HEC using the standard telegraf HTTP output.
+
+If you're using the HTTP output, this serializer knows how to batch the metrics so you don't end up with an HTTP POST per metric.
+
+Th data is output in a format that conforms to the specified Splunk HEC JSON format as found here:
+[Send metrics in JSON format](http://dev.splunk.com/view/event-collector/SP-CAAAFDN).
+
+An example event looks like:
+```javascript
+{
+  "time": 1529708430,
+  "event": "metric",
+  "host": "patas-mbp",
+  "fields": {
+    "_value": 0.6,
+    "cpu": "cpu0",
+    "dc": "mobile",
+    "metric_name": "cpu.usage_user",
+    "user": "ronnocol"
+  }
+}
+```
+In the above snippet, the following keys are dimensions:
+* cpu
+* dc
+* user
+
+## Using with the HTTP output
+
+To send this data to a Splunk HEC, you can use the HTTP output, there are some custom headers that you need to add
+to manage the HEC authorization, here's a sample config for an HTTP output:
+
+```toml
+[[outputs.http]]
+   ## URL is the address to send metrics to
+   url = "https://localhost:8088/services/collector"
+
+   ## Timeout for HTTP message
+   # timeout = "5s"
+
+   ## HTTP method, one of: "POST" or "PUT"
+   # method = "POST"
+
+   ## HTTP Basic Auth credentials
+   # username = "username"
+   # password = "pa$$word"
+
+   ## Optional TLS Config
+   # tls_ca = "/etc/telegraf/ca.pem"
+   # tls_cert = "/etc/telegraf/cert.pem"
+   # tls_key = "/etc/telegraf/key.pem"
+   ## Use TLS but skip chain & host verification
+   # insecure_skip_verify = false
+
+   ## Data format to output.
+   ## Each data format has it's own unique set of configuration options, read
+   ## more about them here:
+   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
+   data_format = "splunkmetric"
+    ## Provides time, index, source overrides for the HEC
+   splunkmetric_hec_routing = true
+
+   ## Additional HTTP headers
+    [outputs.http.headers]
+   # Should be set manually to "application/json" for json data_format
+      Content-Type = "application/json"
+      Authorization = "Splunk xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
+      X-Splunk-Request-Channel = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
+```
+
+## Overrides
+You can override the default values for the HEC token you are using by adding additional tags to the config file.
+
+The following aspects of the token can be overriden with tags:
+* index
+* source
+
+You can either use `[global_tags]` or using a more advanced configuration as documented [here](https://github.com/influxdata/telegraf/blob/master/docs/CONFIGURATION.md).
+
+Such as this example which overrides the index just on the cpu metric:
+```toml
+[[inputs.cpu]]
+  percpu = false
+  totalcpu = true
+  [inputs.cpu.tags]
+    index = "cpu_metrics"
+```
+
+## Using with the File output
+
+You can use the file output when running telegraf on a machine with a Splunk forwarder.
+
+A sample event when `hec_routing` is false (or unset) looks like:
+```javascript
+{
+    "_value": 0.6,
+    "cpu": "cpu0",
+    "dc": "mobile",
+    "metric_name": "cpu.usage_user",
+    "user": "ronnocol",
+    "time": 1529708430
+}
+```
+Data formatted in this manner can be ingested with a simple `props.conf` file that
+looks like this:
+
+```ini
+[telegraf]
+category = Metrics
+description = Telegraf Metrics
+pulldown_type = 1
+DATETIME_CONFIG =
+NO_BINARY_CHECK = true
+SHOULD_LINEMERGE = true
+disabled = false
+INDEXED_EXTRACTIONS = json
+KV_MODE = none
+TIMESTAMP_FIELDS = time
+TIME_FORMAT = %s.%3N
+```
+
+An example configuration of a file based output is: 
+
+```toml
+ # Send telegraf metrics to file(s)
+[[outputs.file]]
+   ## Files to write to, "stdout" is a specially handled file.
+   files = ["/tmp/metrics.out"]
+
+   ## Data format to output.
+   ## Each data format has its own unique set of configuration options, read
+   ## more about them here:
+   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
+   data_format = "splunkmetric"
+   hec_routing = false
+```

plugins/serializers/splunkmetric/splunkmetric.go

@@ -0,0 +1,126 @@
+package splunkmetric
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+
+	"github.com/influxdata/telegraf"
+)
+
+type serializer struct {
+	HecRouting bool
+}
+
+func NewSerializer(splunkmetric_hec_routing bool) (*serializer, error) {
+	s := &serializer{
+		HecRouting: splunkmetric_hec_routing,
+	}
+	return s, nil
+}
+
+func (s *serializer) Serialize(metric telegraf.Metric) ([]byte, error) {
+
+	m, err := s.createObject(metric)
+	if err != nil {
+		return nil, fmt.Errorf("D! [serializer.splunkmetric] Dropping invalid metric: %s", metric.Name())
+	}
+
+	return m, nil
+}
+
+func (s *serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
+
+	var serialized []byte
+
+	for _, metric := range metrics {
+		m, err := s.createObject(metric)
+		if err != nil {
+			return nil, fmt.Errorf("D! [serializer.splunkmetric] Dropping invalid metric: %s", metric.Name())
+		} else if m != nil {
+			serialized = append(serialized, m...)
+		}
+	}
+
+	return serialized, nil
+}
+
+func (s *serializer) createObject(metric telegraf.Metric) (metricGroup []byte, err error) {
+
+	/*  Splunk supports one metric json object, and does _not_ support an array of JSON objects.
+	     ** Splunk has the following required names for the metric store:
+		 ** metric_name: The name of the metric
+		 ** _value:      The value for the metric
+		 ** time:       The timestamp for the metric
+		 ** All other index fields become deminsions.
+	*/
+	type HECTimeSeries struct {
+		Time   float64                `json:"time"`
+		Event  string                 `json:"event"`
+		Host   string                 `json:"host,omitempty"`
+		Index  string                 `json:"index,omitempty"`
+		Source string                 `json:"source,omitempty"`
+		Fields map[string]interface{} `json:"fields"`
+	}
+
+	dataGroup := HECTimeSeries{}
+	var metricJson []byte
+
+	for _, field := range metric.FieldList() {
+
+		if !verifyValue(field.Value) {
+			log.Printf("D! Can not parse value: %v for key: %v", field.Value, field.Key)
+			continue
+		}
+
+		obj := map[string]interface{}{}
+		obj["metric_name"] = metric.Name() + "." + field.Key
+		obj["_value"] = field.Value
+
+		dataGroup.Event = "metric"
+		// Convert ns to float seconds since epoch.
+		dataGroup.Time = float64(metric.Time().UnixNano()) / float64(1000000000)
+		dataGroup.Fields = obj
+
+		// Break tags out into key(n)=value(t) pairs
+		for n, t := range metric.Tags() {
+			if n == "host" {
+				dataGroup.Host = t
+			} else if n == "index" {
+				dataGroup.Index = t
+			} else if n == "source" {
+				dataGroup.Source = t
+			} else {
+				dataGroup.Fields[n] = t
+			}
+		}
+		dataGroup.Fields["metric_name"] = metric.Name() + "." + field.Key
+		dataGroup.Fields["_value"] = field.Value
+
+		switch s.HecRouting {
+		case true:
+			// Output the data as a fields array and host,index,time,source overrides for the HEC.
+			metricJson, err = json.Marshal(dataGroup)
+		default:
+			// Just output the data and the time, useful for file based outuputs
+			dataGroup.Fields["time"] = dataGroup.Time
+			metricJson, err = json.Marshal(dataGroup.Fields)
+		}
+
+		metricGroup = append(metricGroup, metricJson...)
+
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return metricGroup, nil
+}
+
+func verifyValue(v interface{}) bool {
+	switch v.(type) {
+	case string:
+		return false
+	}
+	return true
+}