feat: add new validator expressionIsValidPromQL

Signed-off-by: Martin Chodur <m.chodur@seznam.cz>
FUSAKLA · Jul 12, 2024 · a9d8464 · a9d8464
1 parent 9af9c56
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed: :warning: Unmarshalling of the rule files is strict again, this behavior was unintentionally brought when adding support for yaml comments.
 - Added: support for alert field `keep_firing_for`
 - Added: support for the `query_offset` field in the rule group
+- Added: new validator `expressionIsValidPromQL` to check if the expression is a valid PromQL query
 
 ## [2.14.1]
 - Fixed: error message in the `hasSourceTenantsForMetrics` validator

diff --git a/docs/default_validation.yaml b/docs/default_validation.yaml
@@ -23,6 +23,7 @@ validationRules:
   - name: check-all-rules
     scope: All rules
     validations:
+      - type: expressionIsValidPromQL
       - type: nonEmptyLabels
       - type: expressionDoesNotUseIrate
       - type: validFunctionsOnCounters

diff --git a/docs/validations.md b/docs/validations.md
@@ -20,6 +20,7 @@ All the supported validations are listed here. The validations are grouped by th
       - [`nonEmptyLabels`](#nonemptylabels)
       - [`exclusiveLabels`](#exclusivelabels)
     - [PromQL expression validators](#promql-expression-validators)
+      - [`expressionIsValidPromQL`](#expressionisvalidpromql)
       - [`expressionDoesNotUseMetrics`](#expressiondoesnotusemetrics)
       - [`expressionDoesNotUseLabels`](#expressiondoesnotuselabels)
       - [`expressionDoesNotUseOlderDataThan`](#expressiondoesnotuseolderdatathan)
@@ -205,6 +206,10 @@ params:
 ```
 ### PromQL expression validators
 
+#### `expressionIsValidPromQL`
+
+Fails if the expression is not a valid PromQL query.
+
 #### `expressionDoesNotUseMetrics`
 
 Fails if the rule expression uses metrics matching any of the metric name fully anchored(will be surrounded by `^...$`) regexps.

diff --git a/pkg/validator/config.go b/pkg/validator/config.go
@@ -19,6 +19,7 @@ var registeredUniversalRuleValidators = map[string]validatorCreator{
 	"nonEmptyLabels":       newNonEmptyLabels,
 	"exclusiveLabels":      newExclusiveLabels,
 
+	"expressionIsValidPromQL":              newExpressionIsValidPromQL,
 	"validFunctionsOnCounters":             newValidFunctionsOnCounters,
 	"rateBeforeAggregation":                newRateBeforeAggregation,
 	"expressionDoesNotUseLabels":           newExpressionDoesNotUseLabels,

diff --git a/pkg/validator/expression.go b/pkg/validator/expression.go
@@ -16,6 +16,23 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+func newExpressionIsValidPromQL(_ yaml.Node) (Validator, error) {
+	return &expressionIsValidPromQL{}, nil
+}
+
+type expressionIsValidPromQL struct{}
+
+func (h expressionIsValidPromQL) String() string {
+	return "expression is a valid PromQL query"
+}
+
+func (h expressionIsValidPromQL) Validate(_ unmarshaler.RuleGroup, rule rulefmt.Rule, _ *prometheus.Client) []error {
+	if _, err := parser.ParseExpr(rule.Expr); err != nil {
+		return []error{fmt.Errorf("expression %s is not a valid PromQL query: %w", rule.Expr, err)}
+	}
+	return []error{}
+}
+
 func newExpressionDoesNotUseOlderDataThan(paramsConfig yaml.Node) (Validator, error) {
 	params := struct {
 		Limit model.Duration `yaml:"limit"`

diff --git a/pkg/validator/validator_test.go b/pkg/validator/validator_test.go
@@ -249,6 +249,10 @@ var testCases = []struct {
 	// keepFiringForIsNotLongerThan
 	{name: "keepFiringForIsNotLongerThanOK", validator: keepFiringForIsNotLongerThan{limit: model.Duration(time.Minute)}, rule: rulefmt.Rule{KeepFiringFor: model.Duration(time.Second)}, expectedErrors: 0},
 	{name: "keepFiringForIsNotLongerThanWrong", validator: keepFiringForIsNotLongerThan{limit: model.Duration(time.Minute)}, rule: rulefmt.Rule{KeepFiringFor: model.Duration(time.Minute * 2)}, expectedErrors: 1},
+
+	// expressionIsValidPromQL
+	{name: "expressionIsValidPromQL_OK", validator: expressionIsValidPromQL{}, rule: rulefmt.Rule{Expr: "sum(rate(foo{bar='baz'}[1m]))"}, expectedErrors: 0},
+	{name: "expressionIsValidPromQL_Invalid", validator: expressionIsValidPromQL{}, rule: rulefmt.Rule{Expr: "sum(rate(foo{bar='baz'} | ??? [1m]))"}, expectedErrors: 1},
 }
 
 func Test(t *testing.T) {