feature: count json objects with same value

if we want to count json objects with same values we can use
countbylabel type in the metric configuration

Signed-off-by: Parsa <[email protected]>
Signed-off-by: Parsa <[email protected]>

Author: Parsa

README.md

@@ -59,6 +59,15 @@ metrics:
     count: '{.count}' # dynamic value
     boolean: '{.some_boolean}'
 
+- name: example_count
+  type: countbylabel
+  help: Example of count json labels and
+  path: '{.values[*].state}'
+  labels:
+    environment: beta # static label
+    state: '{}'          # dynamic label
+  mincount: 1
+
 headers:
   X-Dummy: my-test-header
 
@@ -68,6 +77,8 @@ Serving HTTP on 0.0.0.0 port 8000 ...
 $ ./json_exporter --config.file examples/config.yml &
 
 $ curl "http://localhost:7979/probe?target=http://localhost:8000/examples/data.json" | grep ^example
+example_count{environment="beta",state="ACTIVE"} 2
+example_count{environment="beta",state="INACTIVE"} 1
 example_global_value{environment="beta",location="planet-mars"} 1234
 example_value_active{environment="beta",id="id-A"} 1
 example_value_active{environment="beta",id="id-C"} 1

config/config.go

@@ -22,19 +22,21 @@ 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     MetricType
+	Help     string
+	Values   map[string]string
+	Mincount int
 }
 
 type MetricType string
 
 const (
 	ValueScrape  MetricType = "value" // default
 	ObjectScrape MetricType = "object"
+	CountScrape  MetricType = "countbylabel"
 )
 
 // Config contains metrics and headers defining a configuration
@@ -69,6 +71,9 @@ func LoadConfig(configPath string) (Config, error) {
 		if config.Metrics[i].Help == "" {
 			config.Metrics[i].Help = config.Metrics[i].Name
 		}
+		if !(config.Metrics[i].Mincount > 0) {
+			config.Metrics[i].Mincount = 1
+		}
 	}
 
 	return config, nil

examples/config.yml

@@ -19,6 +19,15 @@ metrics:
     count: '{.count}' # dynamic value
     boolean: '{.some_boolean}'
 
+- name: example_count
+  type: countbylabel
+  help: Example of count json labels and
+  path: '{.values[*].state}'
+  labels:
+    environment: beta # static label
+    state: '{}'          # dynamic label
+  mincount: 1
+
 headers:
   X-Dummy: my-test-header
 

exporter/collector.go

@@ -34,6 +34,7 @@ type JSONMetric struct {
 	KeyJSONPath     string
 	ValueJSONPath   string
 	LabelsJSONPaths []string
+	Mincount        int
 }
 
 func (mc JSONMetricCollector) Describe(ch chan<- *prometheus.Desc) {
@@ -44,7 +45,7 @@ func (mc JSONMetricCollector) Describe(ch chan<- *prometheus.Desc) {
 
 func (mc JSONMetricCollector) Collect(ch chan<- prometheus.Metric) {
 	for _, m := range mc.JSONMetrics {
-		if m.ValueJSONPath == "" { // ScrapeType is 'value'
+		if m.ValueJSONPath == "" && m.Mincount == 0 { // ScrapeType is 'value'
 			value, err := extractValue(mc.Logger, mc.Data, m.KeyJSONPath, false)
 			if err != nil {
 				level.Error(mc.Logger).Log("msg", "Failed to extract value for metric", "path", m.KeyJSONPath, "err", err, "metric", m.Desc)
@@ -63,6 +64,42 @@ func (mc JSONMetricCollector) Collect(ch chan<- prometheus.Metric) {
 				level.Error(mc.Logger).Log("msg", "Failed to convert extracted value to float64", "path", m.KeyJSONPath, "value", value, "err", err, "metric", m.Desc)
 				continue
 			}
+		} else if m.Mincount > 0 { // ScrapeType is 'countbylabel'
+			values, err := extractValue(mc.Logger, mc.Data, m.KeyJSONPath, true)
+			if err != nil {
+				level.Error(mc.Logger).Log("msg", "Failed to extract json objects for metric", "err", err, "metric", m.Desc)
+				continue
+			}
+
+			var jsonData []interface{}
+			counts := make(map[interface{}]int)
+
+			if err := json.Unmarshal([]byte(values), &jsonData); err == nil {
+				for _, data := range jsonData {
+					counts[data]++
+				}
+				for data, count := range counts {
+					if count >= m.Mincount {
+						jdata, err := json.Marshal(data)
+						if err != nil {
+							level.Error(mc.Logger).Log("msg", "Failed to marshal data to json", "path", m.ValueJSONPath, "err", err, "metric", m.Desc, "data", data)
+							continue
+						}
+						if err != nil {
+							level.Error(mc.Logger).Log("msg", "Failed to extract value for metric", "path", m.ValueJSONPath, "err", err, "metric", m.Desc)
+							continue
+						}
+
+						ch <- prometheus.MustNewConstMetric(
+							m.Desc,
+							prometheus.UntypedValue,
+							float64(count),
+							extractLabels(mc.Logger, jdata, m.LabelsJSONPaths)...,
+						)
+					}
+				}
+			}
+
 		} else { // ScrapeType is 'object'
 			values, err := extractValue(mc.Logger, mc.Data, m.KeyJSONPath, true)
 			if err != nil {

exporter/util.go

@@ -104,6 +104,24 @@ func CreateMetricsList(c config.Config) ([]JSONMetric, error) {
 				}
 				metrics = append(metrics, jsonMetric)
 			}
+		case config.CountScrape:
+			var variableLabels, variableLabelsValues []string
+			for k, v := range metric.Labels {
+				variableLabels = append(variableLabels, k)
+				variableLabelsValues = append(variableLabelsValues, v)
+			}
+			jsonMetric := JSONMetric{
+				Desc: prometheus.NewDesc(
+					metric.Name,
+					metric.Help,
+					variableLabels,
+					nil,
+				),
+				KeyJSONPath:     metric.Path,
+				Mincount:        metric.Mincount,
+				LabelsJSONPaths: variableLabelsValues,
+			}
+			metrics = append(metrics, jsonMetric)
 		default:
 			return nil, fmt.Errorf("Unknown metric type: '%s', for metric: '%s'", metric.Type, metric.Name)
 		}

test/config/good.yml

@@ -19,3 +19,10 @@ metrics:
     count: '{.count}' # dynamic value
     boolean: '{.some_boolean}'
 
+- name: example_count
+  type: countbylabel
+  help: Example of count object from a json
+  path: '{.values[*].state}'
+  labels:
+    environment: beta # static label
+    state: '{}'          # dynamic label

test/response/good.txt

@@ -1,3 +1,7 @@
+# HELP example_count Example of count object from a json
+# TYPE example_count untyped
+example_count{environment="beta",state="ACTIVE"} 2
+example_count{environment="beta",state="INACTIVE"} 1
 # HELP example_global_value Example of a top-level global value scrape in the json
 # TYPE example_global_value untyped
 example_global_value{environment="beta",location="planet-mars"} 1234