Add metric name validation

examples/validation.yaml

@@ -69,3 +69,8 @@ validationRules:
  - type: expressionDoesNotUseLabels
  params:
  labels: [ "cluster", "locality", "prometheus-type", "replica" ]
+
+ - name: check-metric-name
+ scope: Alert
+ validations:
+ - type: expressionWithNoMetricName

pkg/validator/config.go

@@ -35,6 +35,7 @@ var registeredValidators = map[string]validatorCreator{
  "expressionCanBeEvaluated": newExpressionCanBeEvaluated,
  "expressionUsesExistingLabels": newExpressionUsesExistingLabels,
  "expressionSelectorsMatchesAnything": newExpressionSelectorsMatchesAnything,
+ "expressionWithNoMetricName": newExpressionWithNoMetricName,
 }
 
 func NewFromConfig(config config.ValidatorConfig) (Validator, error) {

pkg/validator/expression.go

@@ -386,3 +386,35 @@ func (h expressionSelectorsMatchesAnything) Validate(rule rulefmt.Rule, promethe
  }
  return errs
 }
+
+func newExpressionWithNoMetricName(paramsConfig yaml.Node) (Validator, error) {
+ params := struct{}{}
+ if err := paramsConfig.Decode(&params); err != nil {
+ return nil, err
+ }
+ return &expressionWithNoMetricName{}, nil
+}
+
+type expressionWithNoMetricName struct{}
+
+func (e expressionWithNoMetricName) String() string {
+ return "expression with no metric name"
+}
+
+func (e expressionWithNoMetricName) Validate(rule rulefmt.Rule, prometheusClient *prometheus.Client) []error {
+ if prometheusClient == nil {
+ log.Error("missing the `prometheus` section of configuration for querying prometheus, skipping check that requires it...")
+ return nil
+ }
+ var errs []error
+ names, err := getExpressionMetricsNames(rule.Expr)
+ if err != nil {
+ return []error{err}
+ }
+ for _, s := range names {
+ if s == "" {
+ errs = append(errs, fmt.Errorf("missing metric name for expression `%s`", rule.Expr))
+ }
+ }
+ return errs
+}

pkg/validator/expression_helpers.go

@@ -2,6 +2,7 @@ package validator
 
 import (
  "fmt"
+ "github.com/prometheus/prometheus/model/labels"
  "github.com/prometheus/prometheus/promql/parser"
 )
 
@@ -46,3 +47,37 @@ func getExpressionSelectors(expr string) ([]string, error) {
  })
  return selectors, nil
 }
+
+func getExpressionMetricsNames(expr string) ([]string, error) {
+ promQl, err := parser.ParseExpr(expr)
+ if err != nil {
+ return []string{}, fmt.Errorf("failed to parse expression `%s`: %s", expr, err)
+ }
+ var names []string
+ parser.Inspect(promQl, func(n parser.Node, ns []parser.Node) error {
+ switch v := n.(type) {
+ case *parser.VectorSelector:
+ names = append(names, getMetricNameFromVectorSelector(v))
+ }
+ return nil
+ })
+ return names, nil
+}
+
+func getMetricNameFromVectorSelector(v *parser.VectorSelector) string {
+ s := &parser.VectorSelector{Name: v.Name}
+ name := s.String()
+ if name == "" {
+ name = getMetricNameFromLabels(v.LabelMatchers)
+ }
+ return name
+}
+
+func getMetricNameFromLabels(labels []*labels.Matcher) string {
+ for _, l := range labels {
+ if l.Name == "__name__" {
+ return l.Value
+ }
+ }
+ return ""
+}

pkg/validator/validator_test.go

@@ -2,15 +2,14 @@ package validator
 
 import (
  "fmt"
- "reflect"
- "regexp"
- "testing"
- "time"
-
  "github.com/fusakla/promruval/v2/pkg/prometheus"
  "github.com/prometheus/common/model"
  "github.com/prometheus/prometheus/model/rulefmt"
  "gotest.tools/assert"
+ "reflect"
+ "regexp"
+ "testing"
+ "time"
 )
 
 var testCases = []struct {
@@ -157,6 +156,24 @@ var testCases = []struct {
  // expressionUsesExistingLabels
  {name: "labelsExists", validator: expressionUsesExistingLabels{}, promClient: prometheus.NewClientMock([]string{"__name__", "foo"}, 0, false, false), rule: rulefmt.Rule{Expr: `up{foo="bar"}`}, expectedErrors: 0},
  {name: "labelsDoesNotExist", validator: expressionUsesExistingLabels{}, promClient: prometheus.NewClientMock([]string{"__name__"}, 0, false, false), rule: rulefmt.Rule{Expr: `up{foo="bar"}`}, expectedErrors: 1},
+
+ {name: "withName", validator: expressionWithNoMetricName{}, promClient: prometheus.NewClientMock(prometheus.NewSeriesResponseMock(2), 0, false, false), rule: rulefmt.Rule{Expr: `up{foo="bar"}`}, expectedErrors: 0},
+ {name: "withNameInLabel", validator: expressionWithNoMetricName{}, promClient: prometheus.NewClientMock(prometheus.NewSeriesResponseMock(2), 0, false, false), rule: rulefmt.Rule{Expr: `{__name__="up", foo="bar"}`}, expectedErrors: 0},
+ {name: "noName", validator: expressionWithNoMetricName{}, promClient: prometheus.NewClientMock(prometheus.NewSeriesResponseMock(2), 0, false, false), rule: rulefmt.Rule{Expr: `{foo="bar"}`}, expectedErrors: 1},
+ {name: "complexExpressionsWithName", validator: expressionWithNoMetricName{}, promClient: prometheus.NewClientMock(prometheus.NewSeriesResponseMock(2), 0, false, false), rule: rulefmt.Rule{Expr: `(
+ sum(rate(http_requests_total{code=~"5..", job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler)
+ /
+ sum(rate(http_requests_total{job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler)
+ ) * 100 > 10
+ and
+ sum(rate(http_requests_total{job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler) > 2`}, expectedErrors: 0},
+ {name: "complexExpressionsNoName", validator: expressionWithNoMetricName{}, promClient: prometheus.NewClientMock(prometheus.NewSeriesResponseMock(2), 0, false, false), rule: rulefmt.Rule{Expr: `(
+ sum(rate(http_requests_total{code=~"5..", job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler)
+ /
+ sum(rate( {job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler)
+ ) * 100 > 10
+ and
+ sum(rate(http_requests_total{job=~"thanos-query",handler!="exemplars"}[5m])) by (role,handler) > 2`}, expectedErrors: 1},
 }
 
 func Test(t *testing.T) {