support custom valuetype like counter, gauge or untyped (prometheus-community#145)

* support custom valuetype like counter, gauge or untyped

Signed-off-by: Ben Ye <ben.ye@bytedance.com>

Author: yeya24

config/config.go

@@ -22,19 +22,28 @@ import (
 
 // Metric contains values that define a metric
 type Metric struct {
-	Name   string
-	Path   string
-	Labels map[string]string
-	Type   MetricType
-	Help   string
-	Values map[string]string
+	Name      string
+	Path      string
+	Labels    map[string]string
+	Type      ScrapeType
+	ValueType ValueType
+	Help      string
+	Values    map[string]string
 }
 
-type MetricType string
+type ScrapeType string
 
 const (
-	ValueScrape  MetricType = "value" // default
-	ObjectScrape MetricType = "object"
+	ValueScrape  ScrapeType = "value" // default
+	ObjectScrape ScrapeType = "object"
+)
+
+type ValueType string
+
+const (
+	ValueTypeGauge   ValueType = "gauge"
+	ValueTypeCounter ValueType = "counter"
+	ValueTypeUntyped ValueType = "untyped"
 )
 
 // Config contains metrics and headers defining a configuration
@@ -69,6 +78,9 @@ func LoadConfig(configPath string) (Config, error) {
 		if config.Metrics[i].Help == "" {
 			config.Metrics[i].Help = config.Metrics[i].Name
 		}
+		if config.Metrics[i].ValueType == "" {
+			config.Metrics[i].ValueType = ValueTypeUntyped
+		}
 	}
 
 	return config, nil

exporter/collector.go

@@ -32,10 +32,11 @@ type JSONMetricCollector struct {
 
 type JSONMetric struct {
 	Desc            *prometheus.Desc
-	Type            config.MetricType
+	Type            config.ScrapeType
 	KeyJSONPath     string
 	ValueJSONPath   string
 	LabelsJSONPaths []string
+	ValueType       prometheus.ValueType
 }
 
 func (mc JSONMetricCollector) Describe(ch chan<- *prometheus.Desc) {

exporter/util.go

@@ -63,8 +63,19 @@ func SanitizeValue(s string) (float64, error) {
 }
 
 func CreateMetricsList(c config.Config) ([]JSONMetric, error) {
-	var metrics []JSONMetric
+	var (
+		metrics   []JSONMetric
+		valueType prometheus.ValueType
+	)
 	for _, metric := range c.Metrics {
+		switch metric.ValueType {
+		case config.ValueTypeGauge:
+			valueType = prometheus.GaugeValue
+		case config.ValueTypeCounter:
+			valueType = prometheus.CounterValue
+		default:
+			valueType = prometheus.UntypedValue
+		}
 		switch metric.Type {
 		case config.ValueScrape:
 			var variableLabels, variableLabelsValues []string
@@ -82,6 +93,7 @@ func CreateMetricsList(c config.Config) ([]JSONMetric, error) {
 				),
 				KeyJSONPath:     metric.Path,
 				LabelsJSONPaths: variableLabelsValues,
+				ValueType:       valueType,
 			}
 			metrics = append(metrics, jsonMetric)
 		case config.ObjectScrape:
@@ -103,6 +115,7 @@ func CreateMetricsList(c config.Config) ([]JSONMetric, error) {
 					KeyJSONPath:     metric.Path,
 					ValueJSONPath:   valuePath,
 					LabelsJSONPaths: variableLabelsValues,
+					ValueType:       valueType,
 				}
 				metrics = append(metrics, jsonMetric)
 			}