prometheus · bboreham · Jun 29, 2022 · Jul 10, 2022 · Jul 10, 2022 · Jul 18, 2022
@@ -631,9 +631,9 @@ func checkRules(filename string, lintSettings lintConfig) (int, []error) {
 			errMessage := fmt.Sprintf("%d duplicate rule(s) found.\n", len(dRules))
 			for _, n := range dRules {
 				errMessage += fmt.Sprintf("Metric: %s\nLabel(s):\n", n.metric)
-				for _, l := range n.label {
+				n.label.Range(func(l labels.Label) {
 					errMessage += fmt.Sprintf("\t%s: %s\n", l.Name, l.Value)
-				}
+				})
 			}
 			errMessage += "Might cause inconsistency while recording expressions"
 			return 0, []error{fmt.Errorf("%w %s", lintError, errMessage)}

@@ -158,14 +158,15 @@ func (importer *ruleImporter) importRule(ctx context.Context, ruleExpr, ruleName
 
 				// Setting the rule labels after the output of the query,
 				// so they can override query output.
-				for _, l := range ruleLabels {
+				ruleLabels.Range(func(l labels.Label) {
 					lb.Set(l.Name, l.Value)
-				}
+				})
 
 				lb.Set(labels.MetricName, ruleName)
+				lbls := lb.Labels(labels.EmptyLabels())
 
 				for _, value := range sample.Values {
-					if err := app.add(ctx, lb.Labels(nil), timestamp.FromTime(value.Timestamp.Time()), float64(value.Value)); err != nil {
+					if err := app.add(ctx, lbls, timestamp.FromTime(value.Timestamp.Time()), float64(value.Value)); err != nil {
 						return fmt.Errorf("add: %w", err)
 					}
 				}

@@ -100,7 +100,7 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				require.Equal(t, 1, len(gRules))
 				require.Equal(t, "rule1", gRules[0].Name())
 				require.Equal(t, "ruleExpr", gRules[0].Query().String())
-				require.Equal(t, 1, len(gRules[0].Labels()))
+				require.Equal(t, 1, gRules[0].Labels().Len())
 
 				group2 := ruleImporter.groups[path2+";group2"]
 				require.NotNil(t, group2)
@@ -109,7 +109,7 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				require.Equal(t, 2, len(g2Rules))
 				require.Equal(t, "grp2_rule1", g2Rules[0].Name())
 				require.Equal(t, "grp2_rule1_expr", g2Rules[0].Query().String())
-				require.Equal(t, 0, len(g2Rules[0].Labels()))
+				require.Equal(t, 0, g2Rules[0].Labels().Len())
 
 				// Backfill all recording rules then check the blocks to confirm the correct data was created.
 				errs = ruleImporter.importAll(ctx)
@@ -132,12 +132,12 @@ func TestBackfillRuleIntegration(t *testing.T) {
 				for selectedSeries.Next() {
 					seriesCount++
 					series := selectedSeries.At()
-					if len(series.Labels()) != 3 {
-						require.Equal(t, 2, len(series.Labels()))
+					if series.Labels().Len() != 3 {
+						require.Equal(t, 2, series.Labels().Len())
 						x := labels.FromStrings("__name__", "grp2_rule1", "name1", "val1")
 						require.Equal(t, x, series.Labels())
 					} else {
-						require.Equal(t, 3, len(series.Labels()))
+						require.Equal(t, 3, series.Labels().Len())
 					}
 					it := series.Iterator(nil)
 					for it.Next() == chunkenc.ValFloat {

@@ -315,7 +315,7 @@ func readPrometheusLabels(r io.Reader, n int) ([]labels.Labels, error) {
 	i := 0
 
 	for scanner.Scan() && i < n {
-		m := make(labels.Labels, 0, 10)
+		m := make([]labels.Label, 0, 10)
 
 		r := strings.NewReplacer("\"", "", "{", "", "}", "")
 		s := r.Replace(scanner.Text())
@@ -325,13 +325,12 @@ func readPrometheusLabels(r io.Reader, n int) ([]labels.Labels, error) {
 			split := strings.Split(labelChunk, ":")
 			m = append(m, labels.Label{Name: split[0], Value: split[1]})
 		}
-		// Order of the k/v labels matters, don't assume we'll always receive them already sorted.
-		sort.Sort(m)
-		h := m.Hash()
+		ml := labels.New(m...) // This sorts by name - order of the k/v labels matters, don't assume we'll always receive them already sorted.
+		h := ml.Hash()
 		if _, ok := hashes[h]; ok {
 			continue
 		}
-		mets = append(mets, m)
+		mets = append(mets, ml)
 		hashes[h] = struct{}{}
 		i++
 	}
@@ -472,19 +471,20 @@ func analyzeBlock(path, blockID string, limit int, runExtended bool) error {
 	}
 	lbls := labels.Labels{}
 	chks := []chunks.Meta{}
+	builder := labels.ScratchBuilder{}
 	for p.Next() {
-		if err = ir.Series(p.At(), &lbls, &chks); err != nil {
+		if err = ir.Series(p.At(), &builder, &lbls, &chks); err != nil {
 			return err
 		}
 		// Amount of the block time range not covered by this series.
 		uncovered := uint64(meta.MaxTime-meta.MinTime) - uint64(chks[len(chks)-1].MaxTime-chks[0].MinTime)
-		for _, lbl := range lbls {
+		lbls.Range(func(lbl labels.Label) {
 			key := lbl.Name + "=" + lbl.Value
 			labelsUncovered[lbl.Name] += uncovered
 			labelpairsUncovered[key] += uncovered
 			labelpairsCount[key]++
 			entries++
-		}
+		})
 	}
 	if p.Err() != nil {
 		return p.Err()
@@ -589,10 +589,11 @@ func analyzeCompaction(block tsdb.BlockReader, indexr tsdb.IndexReader) (err err
 	nBuckets := 10
 	histogram := make([]int, nBuckets)
 	totalChunks := 0
+	var builder labels.ScratchBuilder
 	for postingsr.Next() {
 		lbsl := labels.Labels{}
 		var chks []chunks.Meta
-		if err := indexr.Series(postingsr.At(), &lbsl, &chks); err != nil {
+		if err := indexr.Series(postingsr.At(), &builder, &lbsl, &chks); err != nil {
 			return err
 		}
 

@@ -284,8 +284,8 @@ func (tg *testGroup) test(evalInterval time.Duration, groupOrderMap map[string]i
 					for _, a := range ar.ActiveAlerts() {
 						if a.State == rules.StateFiring {
 							alerts = append(alerts, labelAndAnnotation{
-								Labels:      append(labels.Labels{}, a.Labels...),
-								Annotations: append(labels.Labels{}, a.Annotations...),
+								Labels:      a.Labels.Copy(),
+								Annotations: a.Annotations.Copy(),
 							})
 						}
 					}

@@ -80,7 +80,8 @@ func Load(s string, expandExternalLabels bool, logger log.Logger) (*Config, erro
 		return cfg, nil
 	}
 
-	for i, v := range cfg.GlobalConfig.ExternalLabels {
+	b := labels.ScratchBuilder{}
+	cfg.GlobalConfig.ExternalLabels.Range(func(v labels.Label) {
 		newV := os.Expand(v.Value, func(s string) string {
 			if s == "$" {
 				return "$"
@@ -93,10 +94,10 @@ func Load(s string, expandExternalLabels bool, logger log.Logger) (*Config, erro
 		})
 		if newV != v.Value {
 			level.Debug(logger).Log("msg", "External label replaced", "label", v.Name, "input", v.Value, "output", newV)
-			v.Value = newV
-			cfg.GlobalConfig.ExternalLabels[i] = v
 		}
-	}
+		b.Add(v.Name, newV)
+	})
+	cfg.GlobalConfig.ExternalLabels = b.Labels()
 	return cfg, nil
 }
 
@@ -361,13 +362,16 @@ func (c *GlobalConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		return err
 	}
 
-	for _, l := range gc.ExternalLabels {
+	if err := gc.ExternalLabels.Validate(func(l labels.Label) error {
 		if !model.LabelName(l.Name).IsValid() {
 			return fmt.Errorf("%q is not a valid label name", l.Name)
 		}
 		if !model.LabelValue(l.Value).IsValid() {
 			return fmt.Errorf("%q is not a valid label value", l.Value)
 		}
+		return nil
+	}); err != nil {
+		return err
 	}
 
 	// First set the correct scrape interval, then check that the timeout
@@ -394,7 +398,7 @@ func (c *GlobalConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 // isZero returns true iff the global config is the zero value.
 func (c *GlobalConfig) isZero() bool {
-	return c.ExternalLabels == nil &&
+	return c.ExternalLabels.IsEmpty() &&
 		c.ScrapeInterval == 0 &&
 		c.ScrapeTimeout == 0 &&
 		c.EvaluationInterval == 0 &&