Add instance label to health (up) timeseries.

model/sample.go

@@ -23,6 +23,20 @@ type Sample struct {
 	Timestamp time.Time
 }
 
+func (s Sample) Equal(sample Sample) bool {
+	if !NewFingerprintFromMetric(s.Metric).Equal(NewFingerprintFromMetric(sample.Metric)) {
+		return false
+	}
+	if !s.Timestamp.Equal(sample.Timestamp) {
+		return false
+	}
+	if !s.Value.Equal(sample.Value) {
+		return false
+	}
+
+	return true
+}
+
 type Samples []Sample
 
 func (s Samples) Len() int {

retrieval/target.go

@@ -142,6 +142,7 @@ func (t *target) recordScrapeHealth(results chan format.Result, timestamp time.T
 		metric[label] = value
 	}
 	metric[model.MetricNameLabel] = model.ScrapeHealthMetricName
+	metric[model.InstanceLabel] = model.LabelValue(t.Address())
 
 	healthValue := model.SampleValue(0)
 	if healthy {

retrieval/target_test.go

@@ -14,6 +14,7 @@
 package retrieval
 
 import (
+	"github.com/prometheus/prometheus/model"
 	"github.com/prometheus/prometheus/retrieval/format"
 	"testing"
 	"time"
@@ -30,3 +31,35 @@ func TestTargetScrapeUpdatesState(t *testing.T) {
 		t.Errorf("Expected target state %v, actual: %v", UNREACHABLE, testTarget.state)
 	}
 }
+
+func TestTargetRecordScrapeHealth(t *testing.T) {
+	testTarget := target{
+		scheduler:  literalScheduler{},
+		address:    "http://example.url",
+		baseLabels: model.LabelSet{model.JobLabel: "testjob"},
+	}
+
+	now := time.Now()
+	results := make(chan format.Result)
+	go testTarget.recordScrapeHealth(results, now, true)
+
+	result := <-results
+	actual := result.Sample
+	expected := model.Sample{
+		Metric: model.Metric{
+			model.MetricNameLabel: model.ScrapeHealthMetricName,
+			model.InstanceLabel:   "http://example.url",
+			model.JobLabel:        "testjob",
+		},
+		Timestamp: now,
+		Value:     1,
+	}
+
+	if result.Err != nil {
+		t.Fatalf("Got unexpected error: %v", result.Err)
+	}
+
+	if !actual.Equal(expected) {
+		t.Fatalf("Expected and actual samples not equal. Expected: %v, actual: %v", expected, actual)
+	}
+}