Ruler: add option to skip writing result to ingesters

Signed-off-by: Marco Pracucci <[email protected]>

cmd/mimir/config-descriptor.json

@@ -12642,6 +12642,17 @@
           "fieldFlag": "ruler.independent-rule-evaluation-concurrency-min-duration-percentage",
           "fieldType": "float",
           "fieldCategory": "experimental"
+        },
+        {
+          "kind": "field",
+          "name": "rule_evaluation_write_enabled",
+          "required": false,
+          "desc": "False to disable writing the result of rule evaluation to ingesters. This option can be used for testing purposes.",
+          "fieldValue": null,
+          "fieldDefaultValue": true,
+          "fieldFlag": "ruler.rule-evaluation-write-enabled",
+          "fieldType": "boolean",
+          "fieldCategory": "experimental"
         }
       ],
       "fieldValue": null,

cmd/mimir/help-all.txt.tmpl

@@ -2783,6 +2783,8 @@ Usage of ./cmd/mimir/mimir:
     	The prefix for the keys in the store. Should end with a /. (default "rulers/")
   -ruler.ring.store string
     	Backend storage to use for the ring. Supported values are: consul, etcd, inmemory, memberlist, multi. (default "memberlist")
+  -ruler.rule-evaluation-write-enabled
+    	[experimental] False to disable writing the result of rule evaluation to ingesters. This option can be used for testing purposes. (default true)
   -ruler.rule-path string
     	Directory to store temporary rule files loaded by the Prometheus rule managers. This directory is not required to be persisted between restarts. (default "./data-ruler/")
   -ruler.sync-rules-on-changes-enabled

docs/sources/mimir/configure/configuration-parameters/index.md

@@ -2118,6 +2118,11 @@ tenant_federation:
 # group runtime duration must exceed 50.0% of the evaluation interval.
 # CLI flag: -ruler.independent-rule-evaluation-concurrency-min-duration-percentage
 [independent_rule_evaluation_concurrency_min_duration_percentage: <float> | default = 50]
+
+# (experimental) False to disable writing the result of rule evaluation to
+# ingesters. This option can be used for testing purposes.
+# CLI flag: -ruler.rule-evaluation-write-enabled
+[rule_evaluation_write_enabled: <boolean> | default = true]
 ```
 
 ### ruler_storage

pkg/ruler/compat.go

@@ -141,6 +141,47 @@ func (t *PusherAppendable) Appender(ctx context.Context) storage.Appender {
 	}
 }
 
+type noopAppender struct{}
+
+func (a *noopAppender) Append(_ storage.SeriesRef, l labels.Labels, t int64, v float64) (storage.SeriesRef, error) {
+	return 0, nil
+}
+
+func (a *noopAppender) AppendExemplar(_ storage.SeriesRef, _ labels.Labels, _ exemplar.Exemplar) (storage.SeriesRef, error) {
+	return 0, errors.New("exemplars are unsupported")
+}
+
+func (a *noopAppender) UpdateMetadata(_ storage.SeriesRef, _ labels.Labels, _ metadata.Metadata) (storage.SeriesRef, error) {
+	return 0, errors.New("metadata updates are unsupported")
+}
+
+func (a *noopAppender) AppendHistogram(_ storage.SeriesRef, l labels.Labels, t int64, h *histogram.Histogram, fh *histogram.FloatHistogram) (storage.SeriesRef, error) {
+	return 0, nil
+}
+
+func (a *noopAppender) AppendCTZeroSample(_ storage.SeriesRef, _ labels.Labels, _, _ int64) (storage.SeriesRef, error) {
+	return 0, errors.New("CT zero samples are unsupported")
+}
+
+func (a *noopAppender) Commit() error {
+	return nil
+}
+
+func (a *noopAppender) Rollback() error {
+	return nil
+}
+
+type noopAppendable struct{}
+
+func newNoopAppendable() *noopAppendable {
+	return &noopAppendable{}
+}
+
+// Appender returns a storage.Appender.
+func (t *noopAppendable) Appender(ctx context.Context) storage.Appender {
+	return &noopAppender{}
+}
+
 // RulesLimits defines limits used by Ruler.
 type RulesLimits interface {
 	EvaluationDelay(userID string) time.Duration
@@ -267,7 +308,7 @@ type ManagerFactory func(ctx context.Context, userID string, notifier *notifier.
 
 func DefaultTenantManagerFactory(
 	cfg Config,
-	p Pusher,
+	pusher Pusher,
 	queryable storage.Queryable,
 	queryFunc rules.QueryFunc,
 	concurrencyController MultiTenantRuleConcurrencyController,
@@ -319,8 +360,15 @@ func DefaultTenantManagerFactory(
 		// Wrap the queryable with our custom logic.
 		wrappedQueryable := WrapQueryableWithReadConsistency(queryable, logger)
 
+		var appendeable storage.Appendable
+		if cfg.RuleEvaluationWriteEnabled {
+			appendeable = NewPusherAppendable(pusher, userID, totalWrites, failedWrites)
+		} else {
+			appendeable = newNoopAppendable()
+		}
+
 		return rules.NewManager(&rules.ManagerOptions{
-			Appendable:                 NewPusherAppendable(p, userID, totalWrites, failedWrites),
+			Appendable:                 appendeable,
 			Queryable:                  wrappedQueryable,
 			QueryFunc:                  wrappedQueryFunc,
 			Context:                    user.InjectOrgID(ctx, userID),

pkg/ruler/ruler.go

@@ -140,6 +140,8 @@ type Config struct {
 
 	MaxIndependentRuleEvaluationConcurrency                   int64   `yaml:"max_independent_rule_evaluation_concurrency" category:"experimental"`
 	IndependentRuleEvaluationConcurrencyMinDurationPercentage float64 `yaml:"independent_rule_evaluation_concurrency_min_duration_percentage" category:"experimental"`
+
+	RuleEvaluationWriteEnabled bool `yaml:"rule_evaluation_write_enabled" category:"experimental"`
 }
 
 // Validate config and returns error on failure
@@ -200,6 +202,8 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet, logger log.Logger) {
 	f.Int64Var(&cfg.MaxIndependentRuleEvaluationConcurrency, "ruler.max-independent-rule-evaluation-concurrency", 0, "Number of rules rules that don't have dependencies that we allow to be evaluated concurrently across all tenants. 0 to disable.")
 	f.Float64Var(&cfg.IndependentRuleEvaluationConcurrencyMinDurationPercentage, "ruler.independent-rule-evaluation-concurrency-min-duration-percentage", 50.0, "Minimum threshold of the interval to last rule group runtime duration to allow a rule to be evaluated concurrency. By default, the rule group runtime duration must exceed 50.0% of the evaluation interval.")
 
+	f.BoolVar(&cfg.RuleEvaluationWriteEnabled, "ruler.rule-evaluation-write-enabled", true, "False to disable writing the result of rule evaluation to ingesters. This option can be used for testing purposes.")
+
 	cfg.RingCheckPeriod = 5 * time.Second
 }