Merge pull request #9306 from dgl/zecke/fasta

promtool: Speed up checking for duplicate rules

Running promtool check config on large rule files is rather slow. Improve this by adding a testcase, benchmark and changing the algorithm used to find duplicates.

cmd/promtool/main.go

@@ -24,7 +24,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
-	"reflect"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -48,6 +48,7 @@ import (
 	_ "github.com/prometheus/prometheus/discovery/install" // Register service discovery implementations.
 	"github.com/prometheus/prometheus/discovery/kubernetes"
 	"github.com/prometheus/prometheus/discovery/targetgroup"
+	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/pkg/rulefmt"
 	"github.com/prometheus/prometheus/promql"
 )
@@ -471,8 +472,8 @@ func checkRules(filename string) (int, []error) {
 		fmt.Printf("%d duplicate rule(s) found.\n", len(dRules))
 		for _, n := range dRules {
 			fmt.Printf("Metric: %s\nLabel(s):\n", n.metric)
-			for i, l := range n.label {
-				fmt.Printf("\t%s: %s\n", i, l)
+			for _, l := range n.label {
+				fmt.Printf("\t%s: %s\n", l.Name, l.Value)
 			}
 		}
 		fmt.Println("Might cause inconsistency while recording expressions.")
@@ -483,29 +484,52 @@ func checkRules(filename string) (int, []error) {
 
 type compareRuleType struct {
 	metric string
-	label  map[string]string
+	label  labels.Labels
+}
+
+type compareRuleTypes []compareRuleType
+
+func (c compareRuleTypes) Len() int           { return len(c) }
+func (c compareRuleTypes) Swap(i, j int)      { c[i], c[j] = c[j], c[i] }
+func (c compareRuleTypes) Less(i, j int) bool { return compare(c[i], c[j]) < 0 }
+
+func compare(a, b compareRuleType) int {
+	if res := strings.Compare(a.metric, b.metric); res != 0 {
+		return res
+	}
+
+	return labels.Compare(a.label, b.label)
 }
 
 func checkDuplicates(groups []rulefmt.RuleGroup) []compareRuleType {
 	var duplicates []compareRuleType
+	var rules compareRuleTypes
 
 	for _, group := range groups {
-		for index, rule := range group.Rules {
-			inst := compareRuleType{
+
+		for _, rule := range group.Rules {
+			rules = append(rules, compareRuleType{
 				metric: ruleMetric(rule),
-				label:  rule.Labels,
-			}
-			for i := 0; i < index; i++ {
-				t := compareRuleType{
-					metric: ruleMetric(group.Rules[i]),
-					label:  group.Rules[i].Labels,
-				}
-				if reflect.DeepEqual(t, inst) {
-					duplicates = append(duplicates, t)
-				}
-			}
+				label:  labels.FromMap(rule.Labels),
+			})
 		}
 	}
+	if len(rules) < 2 {
+		return duplicates
+	}
+	sort.Sort(rules)
+
+	last := rules[0]
+	for i := 1; i < len(rules); i++ {
+		if compare(last, rules[i]) == 0 {
+			// Don't add a duplicated rule multiple times.
+			if len(duplicates) == 0 || compare(last, duplicates[len(duplicates)-1]) != 0 {
+				duplicates = append(duplicates, rules[i])
+			}
+		}
+		last = rules[i]
+	}
+
 	return duplicates
 }
 

cmd/promtool/main_test.go

@@ -21,6 +21,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/prometheus/prometheus/pkg/labels"
+	"github.com/prometheus/prometheus/pkg/rulefmt"
 	"github.com/stretchr/testify/require"
 )
 
@@ -118,3 +120,46 @@ func TestCheckSDFile(t *testing.T) {
 		})
 	}
 }
+
+func TestCheckDuplicates(t *testing.T) {
+	cases := []struct {
+		name         string
+		ruleFile     string
+		expectedDups []compareRuleType
+	}{
+		{
+			name:     "no duplicates",
+			ruleFile: "./testdata/rules.yml",
+		},
+		{
+			name:     "duplicate in other group",
+			ruleFile: "./testdata/rules_duplicates.yml",
+			expectedDups: []compareRuleType{
+				{
+					metric: "job:test:count_over_time1m",
+					label:  labels.New(),
+				},
+			},
+		},
+	}
+
+	for _, test := range cases {
+		c := test
+		t.Run(c.name, func(t *testing.T) {
+			rgs, err := rulefmt.ParseFile(c.ruleFile)
+			require.Empty(t, err)
+			dups := checkDuplicates(rgs.Groups)
+			require.Equal(t, c.expectedDups, dups)
+		})
+	}
+}
+
+func BenchmarkCheckDuplicates(b *testing.B) {
+	rgs, err := rulefmt.ParseFile("./testdata/rules_large.yml")
+	require.Empty(b, err)
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		checkDuplicates(rgs.Groups)
+	}
+}

cmd/promtool/testdata/rules_duplicates.yml

@@ -0,0 +1,24 @@
+# This is a rules file with duplicate expressions
+
+groups:
+  - name: base
+    rules:
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))
+
+      # A recording rule that doesn't depend on input series.
+      - record: fixed_data
+        expr: 1
+
+      # Subquery with default resolution test.
+      - record: suquery_interval_test
+        expr: count_over_time(up[5m:])
+
+      # Duplicating
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))
+
+  - name: duplicate
+    rules:
+      - record: job:test:count_over_time1m
+        expr: sum without(instance) (count_over_time(test[1m]))