feat: add new validator maxRulesPerGroup (#61)

* feat: add new validator maxRulesPerGroup Signed-off-by: Martin Chodur <[email protected]> * docs: update docs Signed-off-by: Martin Chodur <[email protected]> --------- Signed-off-by: Martin Chodur <[email protected]>
FUSAKLA · Mar 1, 2024 · 6e5970f · 6e5970f
1 parent 02d2b9c
commit 6e5970f
Show file tree

Hide file tree

Showing 9 changed files with 51 additions and 5 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 - Added new validator `expressionIsWellFormatted` to check if rules are well formatted as `promtool promql format` would do.
+- Added new validator `maxRulesPerGroup` to check if the number of rules in the group is not exceeding the limit.
 
 ## [v2.8.1] - 2024-02-29
 - Fixed param validation of the `hasAllowedEvaluationInterval` validator, if the `maximum` was not set.

diff --git a/docs/validations.md b/docs/validations.md
@@ -39,6 +39,7 @@
     - [`hasValidSourceTenants`](#hasvalidsourcetenants)
     - [`hasAllowedEvaluationInterval`](#hasallowedevaluationinterval)
     - [`hasValidPartialResponseStrategy`](#hasvalidpartialresponsestrategy)
+    - [`maxRulesPerGroup`](#maxrulespergroup)
 
 ## Labels
 
@@ -361,3 +362,12 @@ To enforce the `partial_response_strategy` to be set, set the `mustBeSet` to tru
 params:
   mustBeSet: false
 ```
+
+### `maxRulesPerGroup`
+
+Fails if the rule group has more rules than the specified limit.
+
+```yaml
+params:
+  limit: 10
+```
diff --git a/examples/human_readable.html b/examples/human_readable.html
@@ -50,6 +50,7 @@ <h2><a href="#check-groups">check-groups</a></h2>
 		<li>Group does not have other <code>source_tenants</code> than: <code>tenant1</code>, <code>tenant2</code>, <code>k8s</code></li>
 		<li>Group evaluation interval is between <code>20s</code> and <code>106751d23h47m16s854ms</code> if set</li>
 		<li>Group has valid partial_response_strategy (one of <code>warn</code> or <code>abort</code>) if set</li>
+		<li>Group has at most 10 rules</li>
 	  </ul>
 
   <h2><a href="#check-formatting">check-formatting</a></h2>

diff --git a/examples/human_readable.md b/examples/human_readable.md
@@ -35,6 +35,7 @@ Validation rules:
     - Group does not have other `source_tenants` than: `tenant1`, `tenant2`, `k8s`
     - Group evaluation interval is between `20s` and `106751d23h47m16s854ms` if set
     - Group has valid partial_response_strategy (one of `warn` or `abort`) if set
+    - Group has at most 10 rules
 
   check-formatting
     - All rules expression is well formatted as would `promtool promql format` do or similar online tool such as https://o11y.tools/promqlparser/

diff --git a/examples/validation.yaml b/examples/validation.yaml
@@ -95,6 +95,9 @@ validationRules:
           minimum: "20s"
           intervalMustBeSet: false
       - type: hasValidPartialStrategy
+      - type: maxRulesPerGroup
+        params:
+          limit: 10
 
   - name: check-formatting
     scope: All rules

diff --git a/pkg/unmarshaler/unmarshaler.go b/pkg/unmarshaler/unmarshaler.go
@@ -25,15 +25,15 @@ type RuleGroup struct {
 	Interval                model.Duration    `yaml:"interval,omitempty"`
 	PartialResponseStrategy string            `yaml:"partial_response_strategy,omitempty"`
 	SourceTenants           []string          `yaml:"source_tenants,omitempty"`
-	Rules                   []ruleWithComment `yaml:"rules"`
+	Rules                   []RuleWithComment `yaml:"rules"`
 }
 
-type ruleWithComment struct {
+type RuleWithComment struct {
 	node yaml.Node
 	rule rulefmt.RuleNode
 }
 
-func (r *ruleWithComment) OriginalRule() rulefmt.Rule {
+func (r *RuleWithComment) OriginalRule() rulefmt.Rule {
 	return rulefmt.Rule{
 		Record:      r.rule.Record.Value,
 		Alert:       r.rule.Alert.Value,
@@ -44,7 +44,7 @@ func (r *ruleWithComment) OriginalRule() rulefmt.Rule {
 	}
 }
 
-func (r *ruleWithComment) UnmarshalYAML(value *yaml.Node) error {
+func (r *RuleWithComment) UnmarshalYAML(value *yaml.Node) error {
 	err := value.Decode(&r.node)
 	if err != nil {
 		return err
@@ -56,7 +56,7 @@ func (r *ruleWithComment) UnmarshalYAML(value *yaml.Node) error {
 	return nil
 }
 
-func (r *ruleWithComment) DisabledValidators(commentPrefix string) []string {
+func (r *RuleWithComment) DisabledValidators(commentPrefix string) []string {
 	commentPrefix += ":"
 	var disabledValidators []string
 	allComments := strings.Split(r.node.HeadComment, "\n")

diff --git a/pkg/validator/config.go b/pkg/validator/config.go
@@ -46,6 +46,7 @@ var registeredGroupValidators = map[string]validatorCreator{
 	"hasAllowedSourceTenants":      newHasAllowedSourceTenants,
 	"hasAllowedEvaluationInterval": newHasAllowedEvaluationInterval,
 	"hasValidPartialStrategy":      newHasValidPartialStrategy,
+	"maxRulesPerGroup":             newMaxRulesPerGroup,
 }
 
 var registeredValidators = map[string]validatorCreator{}

diff --git a/pkg/validator/group.go b/pkg/validator/group.go
@@ -132,3 +132,28 @@ func (h hasValidPartialStrategy) Validate(group unmarshaler.RuleGroup, _ rulefmt
 	}
 	return []error{}
 }
+
+func newMaxRulesPerGroup(paramsConfig yaml.Node) (Validator, error) {
+	params := struct {
+		Limit int `yaml:"limit"`
+	}{}
+	if err := paramsConfig.Decode(&params); err != nil {
+		return nil, err
+	}
+	return &maxRulesPerGroup{limit: params.Limit}, nil
+}
+
+type maxRulesPerGroup struct {
+	limit int
+}
+
+func (h maxRulesPerGroup) String() string {
+	return fmt.Sprintf("has at most %d rules", h.limit)
+}
+
+func (h maxRulesPerGroup) Validate(group unmarshaler.RuleGroup, _ rulefmt.Rule, _ *prometheus.Client) []error {
+	if len(group.Rules) > h.limit {
+		return []error{fmt.Errorf("group has %d rules, maximum is %d", len(group.Rules), h.limit)}
+	}
+	return []error{}
+}
diff --git a/pkg/validator/validator_test.go b/pkg/validator/validator_test.go
@@ -229,6 +229,10 @@ var testCases = []struct {
 	{name: "invalidExpression", validator: expressionIsWellFormatted{showFormatted: true}, rule: rulefmt.Rule{Expr: `up     == 1`}, expectedErrors: 1},
 	{name: "validWithCommentThatShouldBeIgnored", validator: expressionIsWellFormatted{showFormatted: true}, rule: rulefmt.Rule{Expr: `up == 1 # fooo`}, expectedErrors: 0},
 	{name: "invalidButWithCommentAndShouldBeSkipped", validator: expressionIsWellFormatted{showFormatted: true, skipExpressionsWithComments: true}, rule: rulefmt.Rule{Expr: `up           == 1 # fooo`}, expectedErrors: 0},
+
+	// maxRulesPerGroup
+	{name: "allowedNumberOfGroups", validator: maxRulesPerGroup{limit: 2}, group: unmarshaler.RuleGroup{Rules: []unmarshaler.RuleWithComment{{}, {}}}, expectedErrors: 0},
+	{name: "tooManyRules", validator: maxRulesPerGroup{limit: 1}, group: unmarshaler.RuleGroup{Rules: []unmarshaler.RuleWithComment{{}, {}}}, expectedErrors: 1},
 }
 
 func Test(t *testing.T) {