Expose some ruler types to ease reuse. (#4312)

Signed-off-by: Peter Štibraný <peter.stibrany@grafana.com>

Author: pstibrany

pkg/ruler/compat.go

@@ -27,7 +27,7 @@ type Pusher interface {
 	Push(context.Context, *cortexpb.WriteRequest) (*cortexpb.WriteResponse, error)
 }
 
-type pusherAppender struct {
+type PusherAppender struct {
 	failedWrites prometheus.Counter
 	totalWrites  prometheus.Counter
 
@@ -39,7 +39,7 @@ type pusherAppender struct {
 	evaluationDelay time.Duration
 }
 
-func (a *pusherAppender) Append(_ uint64, l labels.Labels, t int64, v float64) (uint64, error) {
+func (a *PusherAppender) Append(_ uint64, l labels.Labels, t int64, v float64) (uint64, error) {
 	a.labels = append(a.labels, l)
 
 	// Adapt staleness markers for ruler evaluation delay. As the upstream code
@@ -61,11 +61,11 @@ func (a *pusherAppender) Append(_ uint64, l labels.Labels, t int64, v float64) (
 	return 0, nil
 }
 
-func (a *pusherAppender) AppendExemplar(_ uint64, _ labels.Labels, _ exemplar.Exemplar) (uint64, error) {
+func (a *PusherAppender) AppendExemplar(_ uint64, _ labels.Labels, _ exemplar.Exemplar) (uint64, error) {
 	return 0, errors.New("exemplars are unsupported")
 }
 
-func (a *pusherAppender) Commit() error {
+func (a *PusherAppender) Commit() error {
 	a.totalWrites.Inc()
 
 	// Since a.pusher is distributor, client.ReuseSlice will be called in a.pusher.Push.
@@ -84,7 +84,7 @@ func (a *pusherAppender) Commit() error {
 	return err
 }
 
-func (a *pusherAppender) Rollback() error {
+func (a *PusherAppender) Rollback() error {
 	a.labels = nil
 	a.samples = nil
 	return nil
@@ -112,7 +112,7 @@ func NewPusherAppendable(pusher Pusher, userID string, limits RulesLimits, total
 
 // Appender returns a storage.Appender
 func (t *PusherAppendable) Appender(ctx context.Context) storage.Appender {
-	return &pusherAppender{
+	return &PusherAppender{
 		failedWrites: t.failedWrites,
 		totalWrites:  t.totalWrites,
 
@@ -131,9 +131,9 @@ type RulesLimits interface {
 	RulerMaxRulesPerRuleGroup(userID string) int
 }
 
-// engineQueryFunc returns a new query function using the rules.EngineQueryFunc function
+// EngineQueryFunc returns a new query function using the rules.EngineQueryFunc function
 // and passing an altered timestamp.
-func engineQueryFunc(engine *promql.Engine, q storage.Queryable, overrides RulesLimits, userID string) rules.QueryFunc {
+func EngineQueryFunc(engine *promql.Engine, q storage.Queryable, overrides RulesLimits, userID string) rules.QueryFunc {
 	return func(ctx context.Context, qs string, t time.Time) (promql.Vector, error) {
 		orig := rules.EngineQueryFunc(engine, q)
 		// Delay the evaluation of all rules by a set interval to give a buffer
@@ -143,7 +143,7 @@ func engineQueryFunc(engine *promql.Engine, q storage.Queryable, overrides Rules
 	}
 }
 
-func metricsQueryFunc(qf rules.QueryFunc, queries, failedQueries prometheus.Counter) rules.QueryFunc {
+func MetricsQueryFunc(qf rules.QueryFunc, queries, failedQueries prometheus.Counter) rules.QueryFunc {
 	return func(ctx context.Context, qs string, t time.Time) (promql.Vector, error) {
 		queries.Inc()
 
@@ -204,7 +204,7 @@ func DefaultTenantManagerFactory(cfg Config, p Pusher, q storage.Queryable, engi
 		return rules.NewManager(&rules.ManagerOptions{
 			Appendable:      NewPusherAppendable(p, userID, overrides, totalWrites, failedWrites),
 			Queryable:       q,
-			QueryFunc:       metricsQueryFunc(engineQueryFunc(engine, q, overrides, userID), totalQueries, failedQueries),
+			QueryFunc:       MetricsQueryFunc(EngineQueryFunc(engine, q, overrides, userID), totalQueries, failedQueries),
 			Context:         user.InjectOrgID(ctx, userID),
 			ExternalURL:     cfg.ExternalURL.URL,
 			NotifyFunc:      SendAlerts(notifier, cfg.ExternalURL.URL.String()),

pkg/ruler/compat_test.go

@@ -231,7 +231,7 @@ func TestMetricsQueryFuncErrors(t *testing.T) {
 				return promql.Vector{}, tc.returnedError
 			}
 
-			qf := metricsQueryFunc(mockFunc, queries, failures)
+			qf := MetricsQueryFunc(mockFunc, queries, failures)
 
 			_, err := qf(context.Background(), "test", time.Now())
 			require.Equal(t, tc.returnedError, err)