Merge pull request #8 from machadovilaca/add-collector-const-labels

Add collector const labels

pkg/operatormetrics/collector.go

@@ -20,9 +20,10 @@ type Collector struct {
 }
 
 type CollectorResult struct {
-	Metric Metric
-	Labels []string
-	Value  float64
+	Metric      Metric
+	Labels      []string
+	ConstLabels map[string]string
+	Value       float64
 }
 
 func (c Collector) hash() string {
@@ -73,11 +74,19 @@ func collectValue(ch chan<- prometheus.Metric, metric Metric, cr CollectorResult
 		return fmt.Errorf("encountered unsupported type for collector %v", metric.GetType())
 	}
 
+	labels := map[string]string{}
+	for k, v := range cr.ConstLabels {
+		labels[k] = v
+	}
+	for k, v := range metric.GetOpts().ConstLabels {
+		labels[k] = v
+	}
+
 	desc := prometheus.NewDesc(
 		metric.GetOpts().Name,
 		metric.GetOpts().Help,
 		metric.GetOpts().labels,
-		metric.GetOpts().ConstLabels,
+		labels,
 	)
 
 	cm, err := prometheus.NewConstMetric(desc, mType, cr.Value, cr.Labels...)

pkg/operatormetrics/collector_test.go

@@ -73,5 +73,36 @@ var _ = Describe("Collector", func() {
 
 			Expect(ch).NotTo(Receive())
 		})
+
+		It("should collect metrics with const labels added on collection time", func() {
+			counter := NewCounter(testCounterOpts)
+
+			collector := Collector{
+				Metrics: []Metric{counter},
+				CollectCallback: func() []CollectorResult {
+					return []CollectorResult{
+						{
+							Metric: counter,
+							Labels: nil,
+							ConstLabels: map[string]string{
+								"important_info": "xpto",
+							},
+							Value: 5,
+						},
+					}
+				},
+			}
+
+			err := RegisterCollector(collector)
+			Expect(err).NotTo(HaveOccurred())
+
+			ch := make(chan prometheus.Metric, 1)
+			go collector.Collect(ch)
+
+			metricCounter := <-ch
+
+			Expect(metricCounter.Desc().String()).To(ContainSubstring(testCounterOpts.Name))
+			Expect(metricCounter.Desc().String()).To(ContainSubstring("constLabels: {important_info=\"xpto\"}"))
+		})
 	})
 })