Add test for same label set in targets

Signed-off-by: darshanime <deathbullet@gmail.com>

scrape/manager.go

@@ -213,14 +213,13 @@ func (m *Manager) reload() {
 			if t, ok := activeTargets[target.labels.Hash()]; ok {
 				level.Warn(m.logger).Log(
 					"msg", "Found targets with same labels after relabelling",
-					"target", t.URL().String(),
-					"target", target.URL().String(),
+					"target", t.DiscoveredLabels().Get(model.AddressLabel),
+					"target", target.DiscoveredLabels().Get(model.AddressLabel),
 				)
 			}
 			activeTargets[target.labels.Hash()] = target
 		}
 	}
-
 }
 
 // setOffsetSeed calculates a global offsetSeed per server relying on extra label set.

scrape/manager_test.go

@@ -622,6 +622,32 @@ func TestManagerTargetsUpdates(t *testing.T) {
 	}
 }
 
+func TestManagerDuplicateAfterRelabellingWarning(t *testing.T) {
+	var output []interface{}
+	logger := log.Logger(log.LoggerFunc(func(keyvals ...interface{}) error {
+		output = keyvals
+		return nil
+	}))
+
+	opts := Options{}
+	testRegistry := prometheus.NewRegistry()
+	m, err := NewManager(&opts, logger, nil, testRegistry)
+	require.NoError(t, err)
+
+	m.scrapePools = map[string]*scrapePool{}
+	sp := &scrapePool{
+		activeTargets: map[uint64]*Target{},
+	}
+	sp.activeTargets[uint64(0)] = &Target{discoveredLabels: labels.FromStrings("__address__", "foo")}
+	sp.activeTargets[uint64(1)] = &Target{discoveredLabels: labels.FromStrings("__address__", "bar")}
+	m.scrapePools["default"] = sp
+
+	m.reload()
+	require.Contains(t, output, "Found targets with same labels after relabelling")
+	require.Contains(t, output, "foo")
+	require.Contains(t, output, "bar")
+}
+
 func TestSetOffsetSeed(t *testing.T) {
 	getConfig := func(prometheus string) *config.Config {
 		cfgText := `