promql.Engine: Add Close method

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

cmd/prometheus/main.go

@@ -955,12 +955,18 @@ func main() {
 	listener, err := webHandler.Listener()
 	if err != nil {
 		level.Error(logger).Log("msg", "Unable to start web listener", "err", err)
+		if err := queryEngine.Close(); err != nil {
+			level.Warn(logger).Log("msg", "Closing query engine failed", "err", err)
+		}
 		os.Exit(1)
 	}
 
 	err = toolkit_web.Validate(*webConfig)
 	if err != nil {
 		level.Error(logger).Log("msg", "Unable to validate web configuration file", "err", err)
+		if err := queryEngine.Close(); err != nil {
+			level.Warn(logger).Log("msg", "Closing query engine failed", "err", err)
+		}
 		os.Exit(1)
 	}
 
@@ -982,6 +988,9 @@ func main() {
 				case <-cancel:
 					reloadReady.Close()
 				}
+				if err := queryEngine.Close(); err != nil {
+					level.Warn(logger).Log("msg", "Closing query engine failed", "err", err)
+				}
 				return nil
 			},
 			func(err error) {

promql/bench_test.go

@@ -21,6 +21,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/prometheus/prometheus/model/histogram"
 	"github.com/prometheus/prometheus/model/labels"
 	"github.com/prometheus/prometheus/promql"
@@ -257,6 +259,9 @@ func BenchmarkRangeQuery(b *testing.B) {
 		Timeout:    100 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	b.Cleanup(func() {
+		require.NoError(b, engine.Close())
+	})
 
 	const interval = 10000 // 10s interval.
 	// A day of data plus 10k steps.
@@ -340,6 +345,9 @@ func BenchmarkNativeHistograms(b *testing.B) {
 	for _, tc := range cases {
 		b.Run(tc.name, func(b *testing.B) {
 			ng := promql.NewEngine(opts)
+			b.Cleanup(func() {
+				require.NoError(b, ng.Close())
+			})
 			for i := 0; i < b.N; i++ {
 				qry, err := ng.NewRangeQuery(context.Background(), testStorage, nil, tc.query, start, end, step)
 				if err != nil {

promql/engine.go

@@ -19,6 +19,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"math"
 	"reflect"
 	"runtime"
@@ -271,6 +272,8 @@ func contextErr(err error, env string) error {
 //
 // 2) Enforcement of the maximum number of concurrent queries.
 type QueryTracker interface {
+	io.Closer
+
 	// GetMaxConcurrent returns maximum number of concurrent queries that are allowed by this tracker.
 	GetMaxConcurrent() int
 
@@ -423,6 +426,14 @@ func NewEngine(opts EngineOpts) *Engine {
 	}
 }
 
+// Close closes ng.
+func (ng *Engine) Close() error {
+	if ng.activeQueryTracker != nil {
+		return ng.activeQueryTracker.Close()
+	}
+	return nil
+}
+
 // SetQueryLogger sets the query logger.
 func (ng *Engine) SetQueryLogger(l QueryLogger) {
 	ng.queryLoggerLock.Lock()

promql/engine_test.go

@@ -18,7 +18,6 @@ import (
 	"errors"
 	"fmt"
 	"math"
-	"os"
 	"sort"
 	"strconv"
 	"sync"
@@ -55,14 +54,7 @@ func TestMain(m *testing.M) {
 func TestQueryConcurrency(t *testing.T) {
 	maxConcurrency := 10
 
-	dir, err := os.MkdirTemp("", "test_concurrency")
-	require.NoError(t, err)
-	defer os.RemoveAll(dir)
-	queryTracker := promql.NewActiveQueryTracker(dir, maxConcurrency, nil)
-	t.Cleanup(func() {
-		require.NoError(t, queryTracker.Close())
-	})
-
+	queryTracker := promql.NewActiveQueryTracker(t.TempDir(), maxConcurrency, nil)
 	opts := promql.EngineOpts{
 		Logger:             nil,
 		Reg:                nil,
@@ -72,13 +64,18 @@ func TestQueryConcurrency(t *testing.T) {
 	}
 
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ctx, cancelCtx := context.WithCancel(context.Background())
-	defer cancelCtx()
+	t.Cleanup(cancelCtx)
 
 	block := make(chan struct{})
 	processing := make(chan struct{})
 	done := make(chan int)
-	defer close(done)
+	t.Cleanup(func() {
+		close(done)
+	})
 
 	f := func(context.Context) error {
 		select {
@@ -164,6 +161,9 @@ func TestQueryTimeout(t *testing.T) {
 		Timeout:    5 * time.Millisecond,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ctx, cancelCtx := context.WithCancel(context.Background())
 	defer cancelCtx()
 
@@ -263,6 +263,9 @@ func TestQueryError(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	errStorage := promql.ErrStorage{errors.New("storage error")}
 	queryable := storage.QueryableFunc(func(mint, maxt int64) (storage.Querier, error) {
 		return &errQuerier{err: errStorage}, nil
@@ -597,6 +600,9 @@ func TestSelectHintsSetCorrectly(t *testing.T) {
 	} {
 		t.Run(tc.query, func(t *testing.T) {
 			engine := promql.NewEngine(opts)
+			t.Cleanup(func() {
+				require.NoError(t, engine.Close())
+			})
 			hintsRecorder := &noopHintRecordingQueryable{}
 
 			var (
@@ -628,6 +634,9 @@ func TestEngineShutdown(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ctx, cancelCtx := context.WithCancel(context.Background())
 
 	block := make(chan struct{})
@@ -763,7 +772,7 @@ load 10s
 		t.Run(fmt.Sprintf("%d query=%s", i, c.Query), func(t *testing.T) {
 			var err error
 			var qry promql.Query
-			engine := newTestEngine()
+			engine := newTestEngine(t)
 			if c.Interval == 0 {
 				qry, err = engine.NewInstantQuery(context.Background(), storage, nil, c.Query, c.Start)
 			} else {
@@ -1305,7 +1314,7 @@ load 10s
 	for _, c := range cases {
 		t.Run(c.Query, func(t *testing.T) {
 			opts := promql.NewPrometheusQueryOpts(true, 0)
-			engine := promqltest.NewTestEngine(true, 0, promqltest.DefaultMaxSamplesPerQuery)
+			engine := promqltest.NewTestEngine(t, true, 0, promqltest.DefaultMaxSamplesPerQuery)
 
 			runQuery := func(expErr error) *stats.Statistics {
 				var err error
@@ -1332,7 +1341,7 @@ load 10s
 			if c.SkipMaxCheck {
 				return
 			}
-			engine = promqltest.NewTestEngine(true, 0, stats.Samples.PeakSamples-1)
+			engine = promqltest.NewTestEngine(t, true, 0, stats.Samples.PeakSamples-1)
 			runQuery(promql.ErrTooManySamples(env))
 		})
 	}
@@ -1485,7 +1494,7 @@ load 10s
 
 	for _, c := range cases {
 		t.Run(c.Query, func(t *testing.T) {
-			engine := newTestEngine()
+			engine := newTestEngine(t)
 			testFunc := func(expError error) {
 				var err error
 				var qry promql.Query
@@ -1506,18 +1515,18 @@ load 10s
 			}
 
 			// Within limit.
-			engine = promqltest.NewTestEngine(false, 0, c.MaxSamples)
+			engine = promqltest.NewTestEngine(t, false, 0, c.MaxSamples)
 			testFunc(nil)
 
 			// Exceeding limit.
-			engine = promqltest.NewTestEngine(false, 0, c.MaxSamples-1)
+			engine = promqltest.NewTestEngine(t, false, 0, c.MaxSamples-1)
 			testFunc(promql.ErrTooManySamples(env))
 		})
 	}
 }
 
 func TestAtModifier(t *testing.T) {
-	engine := newTestEngine()
+	engine := newTestEngine(t)
 	storage := promqltest.LoadedStorage(t, `
 load 10s
   metric{job="1"} 0+1x1000
@@ -1995,7 +2004,7 @@ func TestSubquerySelector(t *testing.T) {
 		},
 	} {
 		t.Run("", func(t *testing.T) {
-			engine := newTestEngine()
+			engine := newTestEngine(t)
 			storage := promqltest.LoadedStorage(t, tst.loadString)
 			t.Cleanup(func() { storage.Close() })
 
@@ -2016,7 +2025,7 @@ func TestSubquerySelector(t *testing.T) {
 }
 
 func TestTimestampFunction_StepsMoreOftenThanSamples(t *testing.T) {
-	engine := newTestEngine()
+	engine := newTestEngine(t)
 	storage := promqltest.LoadedStorage(t, `
 load 1m
   metric 0+1x1000
@@ -2086,6 +2095,9 @@ func TestQueryLogger_basic(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	queryExec := func() {
 		ctx, cancelCtx := context.WithCancel(context.Background())
@@ -2137,6 +2149,9 @@ func TestQueryLogger_fields(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	f1 := NewFakeQueryLogger()
 	engine.SetQueryLogger(f1)
@@ -2166,6 +2181,9 @@ func TestQueryLogger_error(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	f1 := NewFakeQueryLogger()
 	engine.SetQueryLogger(f1)
@@ -3049,6 +3067,9 @@ func TestEngineOptsValidation(t *testing.T) {
 
 	for _, c := range cases {
 		eng := promql.NewEngine(c.opts)
+		t.Cleanup(func() {
+			require.NoError(t, eng.Close())
+		})
 		_, err1 := eng.NewInstantQuery(context.Background(), nil, nil, c.query, time.Unix(10, 0))
 		_, err2 := eng.NewRangeQuery(context.Background(), nil, nil, c.query, time.Unix(0, 0), time.Unix(10, 0), time.Second)
 		if c.fail {
@@ -3208,7 +3229,7 @@ func TestRangeQuery(t *testing.T) {
 	}
 	for _, c := range cases {
 		t.Run(c.Name, func(t *testing.T) {
-			engine := newTestEngine()
+			engine := newTestEngine(t)
 			storage := promqltest.LoadedStorage(t, c.Load)
 			t.Cleanup(func() { storage.Close() })
 
@@ -3342,7 +3363,7 @@ func TestNativeHistogram_Sum_Count_Add_AvgOperator(t *testing.T) {
 				seriesName := "sparse_histogram_series"
 				seriesNameOverTime := "sparse_histogram_series_over_time"
 
-				engine := newTestEngine()
+				engine := newTestEngine(t)
 
 				ts := idx0 * int64(10*time.Minute/time.Millisecond)
 				app := storage.Appender(context.Background())
@@ -3612,7 +3633,7 @@ func TestNativeHistogram_SubOperator(t *testing.T) {
 	for _, c := range cases {
 		for _, floatHisto := range []bool{true, false} {
 			t.Run(fmt.Sprintf("floatHistogram=%t %d", floatHisto, idx0), func(t *testing.T) {
-				engine := newTestEngine()
+				engine := newTestEngine(t)
 				storage := teststorage.New(t)
 				t.Cleanup(func() { storage.Close() })
 
@@ -3773,7 +3794,7 @@ func TestNativeHistogram_MulDivOperator(t *testing.T) {
 				seriesName := "sparse_histogram_series"
 				floatSeriesName := "float_series"
 
-				engine := newTestEngine()
+				engine := newTestEngine(t)
 
 				ts := idx0 * int64(10*time.Minute/time.Millisecond)
 				app := storage.Appender(context.Background())
@@ -3896,7 +3917,7 @@ metric 0 1 2
 	for _, c := range cases {
 		c := c
 		t.Run(c.name, func(t *testing.T) {
-			engine := promqltest.NewTestEngine(false, c.engineLookback, promqltest.DefaultMaxSamplesPerQuery)
+			engine := promqltest.NewTestEngine(t, false, c.engineLookback, promqltest.DefaultMaxSamplesPerQuery)
 			storage := promqltest.LoadedStorage(t, load)
 			t.Cleanup(func() { storage.Close() })
 

promql/functions_test.go

@@ -40,6 +40,9 @@ func TestDeriv(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	a := storage.Appender(context.Background())
 

promql/promql_test.go

@@ -27,12 +27,12 @@ import (
 	"github.com/prometheus/prometheus/util/teststorage"
 )
 
-func newTestEngine() *promql.Engine {
-	return promqltest.NewTestEngine(false, 0, promqltest.DefaultMaxSamplesPerQuery)
+func newTestEngine(t *testing.T) *promql.Engine {
+	return promqltest.NewTestEngine(t, false, 0, promqltest.DefaultMaxSamplesPerQuery)
 }
 
 func TestEvaluations(t *testing.T) {
-	promqltest.RunBuiltinTests(t, newTestEngine())
+	promqltest.RunBuiltinTests(t, newTestEngine(t))
 }
 
 // Run a lot of queries at the same time, to check for race conditions.
@@ -46,6 +46,9 @@ func TestConcurrentRangeQueries(t *testing.T) {
 		Timeout:    100 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	const interval = 10000 // 10s interval.
 	// A day of data plus 10k steps.

promql/promqltest/test.go

@@ -72,8 +72,8 @@ func LoadedStorage(t testutil.T, input string) *teststorage.TestStorage {
 	return test.storage
 }
 
-func NewTestEngine(enablePerStepStats bool, lookbackDelta time.Duration, maxSamples int) *promql.Engine {
-	return promql.NewEngine(promql.EngineOpts{
+func NewTestEngine(t *testing.T, enablePerStepStats bool, lookbackDelta time.Duration, maxSamples int) *promql.Engine {
+	ng := promql.NewEngine(promql.EngineOpts{
 		Logger:                   nil,
 		Reg:                      nil,
 		MaxSamples:               maxSamples,
@@ -84,6 +84,10 @@ func NewTestEngine(enablePerStepStats bool, lookbackDelta time.Duration, maxSamp
 		EnablePerStepStats:       enablePerStepStats,
 		LookbackDelta:            lookbackDelta,
 	})
+	t.Cleanup(func() {
+		require.NoError(t, ng.Close())
+	})
+	return ng
 }
 
 // RunBuiltinTests runs an acceptance test suite against the provided engine.
@@ -1073,7 +1077,11 @@ func (ll *LazyLoader) Storage() storage.Storage {
 // Close closes resources associated with the LazyLoader.
 func (ll *LazyLoader) Close() error {
 	ll.cancelCtx()
-	return ll.storage.Close()
+	err := ll.queryEngine.Close()
+	if sErr := ll.storage.Close(); sErr != nil {
+		return errors.Join(sErr, err)
+	}
+	return err
 }
 
 func makeInt64Pointer(val int64) *int64 {

promql/promqltest/test_test.go

@@ -451,7 +451,7 @@ eval range from 0 to 5m step 5m testmetric
 
 	for name, testCase := range testCases {
 		t.Run(name, func(t *testing.T) {
-			err := runTest(t, testCase.input, NewTestEngine(false, 0, DefaultMaxSamplesPerQuery))
+			err := runTest(t, testCase.input, NewTestEngine(t, false, 0, DefaultMaxSamplesPerQuery))
 
 			if testCase.expectedError == "" {
 				require.NoError(t, err)

rules/alerting_test.go

@@ -36,7 +36,9 @@ import (
 	"github.com/prometheus/prometheus/util/testutil"
 )
 
-var testEngine = promql.NewEngine(promql.EngineOpts{
+func testEngine(tb testing.TB) *promql.Engine {
+	tb.Helper()
+	e := promql.NewEngine(promql.EngineOpts{
 		Logger:                   nil,
 		Reg:                      nil,
 		MaxSamples:               10000,
@@ -46,6 +48,11 @@ var testEngine = promql.NewEngine(promql.EngineOpts{
 		EnableNegativeOffset:     true,
 		EnablePerStepStats:       true,
 	})
+	tb.Cleanup(func() {
+		require.NoError(tb, e.Close())
+	})
+	return e
+}
 
 func TestAlertingRuleState(t *testing.T) {
 	tests := []struct {
@@ -225,12 +232,14 @@ func TestAlertingRuleLabelsUpdate(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
+
 	baseTime := time.Unix(0, 0)
 	for i, result := range results {
 		t.Logf("case %d", i)
 		evalTime := baseTime.Add(time.Duration(i) * time.Minute)
 		result[0].T = timestamp.FromTime(evalTime)
-		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 		require.NoError(t, err)
 
 		var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
@@ -247,7 +256,7 @@ func TestAlertingRuleLabelsUpdate(t *testing.T) {
 		testutil.RequireEqual(t, result, filteredRes)
 	}
 	evalTime := baseTime.Add(time.Duration(len(results)) * time.Minute)
-	res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+	res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 	require.NoError(t, err)
 	require.Empty(t, res)
 }
@@ -309,13 +318,15 @@ func TestAlertingRuleExternalLabelsInTemplate(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
+
 	evalTime := time.Unix(0, 0)
 	result[0].T = timestamp.FromTime(evalTime)
 	result[1].T = timestamp.FromTime(evalTime)
 
 	var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
 	res, err := ruleWithoutExternalLabels.Eval(
-		context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0,
+		context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0,
 	)
 	require.NoError(t, err)
 	for _, smpl := range res {
@@ -329,7 +340,7 @@ func TestAlertingRuleExternalLabelsInTemplate(t *testing.T) {
 	}
 
 	res, err = ruleWithExternalLabels.Eval(
-		context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0,
+		context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0,
 	)
 	require.NoError(t, err)
 	for _, smpl := range res {
@@ -406,9 +417,11 @@ func TestAlertingRuleExternalURLInTemplate(t *testing.T) {
 	result[0].T = timestamp.FromTime(evalTime)
 	result[1].T = timestamp.FromTime(evalTime)
 
+	ng := testEngine(t)
+
 	var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
 	res, err := ruleWithoutExternalURL.Eval(
-		context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0,
+		context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0,
 	)
 	require.NoError(t, err)
 	for _, smpl := range res {
@@ -422,7 +435,7 @@ func TestAlertingRuleExternalURLInTemplate(t *testing.T) {
 	}
 
 	res, err = ruleWithExternalURL.Eval(
-		context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0,
+		context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0,
 	)
 	require.NoError(t, err)
 	for _, smpl := range res {
@@ -475,9 +488,11 @@ func TestAlertingRuleEmptyLabelFromTemplate(t *testing.T) {
 	evalTime := time.Unix(0, 0)
 	result[0].T = timestamp.FromTime(evalTime)
 
+	ng := testEngine(t)
+
 	var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
 	res, err := rule.Eval(
-		context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0,
+		context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0,
 	)
 	require.NoError(t, err)
 	for _, smpl := range res {
@@ -520,6 +535,8 @@ instance: {{ $v.Labels.instance }}, value: {{ printf "%.0f" $v.Value }};
 	)
 	evalTime := time.Unix(0, 0)
 
+	ng := testEngine(t)
+
 	startQueryCh := make(chan struct{})
 	getDoneCh := make(chan struct{})
 	slowQueryFunc := func(ctx context.Context, q string, ts time.Time) (promql.Vector, error) {
@@ -533,7 +550,7 @@ instance: {{ $v.Labels.instance }}, value: {{ printf "%.0f" $v.Value }};
 				require.Fail(t, "unexpected blocking when template expanding.")
 			}
 		}
-		return EngineQueryFunc(testEngine, storage)(ctx, q, ts)
+		return EngineQueryFunc(ng, storage)(ctx, q, ts)
 	}
 	go func() {
 		<-startQueryCh
@@ -579,6 +596,9 @@ func TestAlertingRuleDuplicate(t *testing.T) {
 	}
 
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ctx, cancelCtx := context.WithCancel(context.Background())
 	defer cancelCtx()
 
@@ -642,9 +662,9 @@ func TestAlertingRuleLimit(t *testing.T) {
 	)
 
 	evalTime := time.Unix(0, 0)
-
+	ng := testEngine(t)
 	for _, test := range tests {
-		switch _, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, test.limit); {
+		switch _, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, test.limit); {
 		case err != nil:
 			require.EqualError(t, err, test.err)
 		case test.err != "":
@@ -866,12 +886,13 @@ func TestKeepFiringFor(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
 	baseTime := time.Unix(0, 0)
 	for i, result := range results {
 		t.Logf("case %d", i)
 		evalTime := baseTime.Add(time.Duration(i) * time.Minute)
 		result[0].T = timestamp.FromTime(evalTime)
-		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 		require.NoError(t, err)
 
 		var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
@@ -888,7 +909,7 @@ func TestKeepFiringFor(t *testing.T) {
 		testutil.RequireEqual(t, result, filteredRes)
 	}
 	evalTime := baseTime.Add(time.Duration(len(results)) * time.Minute)
-	res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+	res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 	require.NoError(t, err)
 	require.Empty(t, res)
 }
@@ -923,9 +944,10 @@ func TestPendingAndKeepFiringFor(t *testing.T) {
 		F: 1,
 	}
 
+	ng := testEngine(t)
 	baseTime := time.Unix(0, 0)
 	result.T = timestamp.FromTime(baseTime)
-	res, err := rule.Eval(context.TODO(), baseTime, EngineQueryFunc(testEngine, storage), nil, 0)
+	res, err := rule.Eval(context.TODO(), baseTime, EngineQueryFunc(ng, storage), nil, 0)
 	require.NoError(t, err)
 
 	require.Len(t, res, 2)
@@ -940,7 +962,7 @@ func TestPendingAndKeepFiringFor(t *testing.T) {
 	}
 
 	evalTime := baseTime.Add(time.Minute)
-	res, err = rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+	res, err = rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 	require.NoError(t, err)
 	require.Empty(t, res)
 }

rules/manager_test.go

@@ -157,12 +157,13 @@ func TestAlertingRule(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
 	for i, test := range tests {
 		t.Logf("case %d", i)
 
 		evalTime := baseTime.Add(test.time)
 
-		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 		require.NoError(t, err)
 
 		var filteredRes promql.Vector // After removing 'ALERTS_FOR_STATE' samples.
@@ -296,6 +297,7 @@ func TestForStateAddSamples(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
 	var forState float64
 	for i, test := range tests {
 		t.Logf("case %d", i)
@@ -308,7 +310,7 @@ func TestForStateAddSamples(t *testing.T) {
 			forState = float64(value.StaleNaN)
 		}
 
-		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, 0)
+		res, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, 0)
 		require.NoError(t, err)
 
 		var filteredRes promql.Vector // After removing 'ALERTS' samples.
@@ -359,8 +361,9 @@ func TestForStateRestore(t *testing.T) {
 	expr, err := parser.ParseExpr(`http_requests{group="canary", job="app-server"} < 100`)
 	require.NoError(t, err)
 
+	ng := testEngine(t)
 	opts := &ManagerOptions{
-		QueryFunc:       EngineQueryFunc(testEngine, storage),
+		QueryFunc:       EngineQueryFunc(ng, storage),
 		Appendable:      storage,
 		Queryable:       storage,
 		Context:         context.Background(),
@@ -528,6 +531,9 @@ func TestStaleness(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(engineOpts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	opts := &ManagerOptions{
 		QueryFunc:  EngineQueryFunc(engine, st),
 		Appendable: st,
@@ -720,6 +726,9 @@ func TestUpdate(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ruleManager := NewManager(&ManagerOptions{
 		Appendable: st,
 		Queryable:  st,
@@ -858,6 +867,9 @@ func TestNotify(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(engineOpts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	var lastNotified []*Alert
 	notifyFunc := func(ctx context.Context, expr string, alerts ...*Alert) {
 		lastNotified = alerts
@@ -933,6 +945,9 @@ func TestMetricsUpdate(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ruleManager := NewManager(&ManagerOptions{
 		Appendable: storage,
 		Queryable:  storage,
@@ -1007,6 +1022,9 @@ func TestGroupStalenessOnRemoval(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ruleManager := NewManager(&ManagerOptions{
 		Appendable: storage,
 		Queryable:  storage,
@@ -1084,6 +1102,9 @@ func TestMetricsStalenessOnManagerShutdown(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ruleManager := NewManager(&ManagerOptions{
 		Appendable: storage,
 		Queryable:  storage,
@@ -1186,6 +1207,9 @@ func TestRuleHealthUpdates(t *testing.T) {
 		Timeout:    10 * time.Second,
 	}
 	engine := promql.NewEngine(engineOpts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	opts := &ManagerOptions{
 		QueryFunc:  EngineQueryFunc(engine, st),
 		Appendable: st,
@@ -1282,9 +1306,10 @@ func TestRuleGroupEvalIterationFunc(t *testing.T) {
 		},
 	}
 
+	ng := testEngine(t)
 	testFunc := func(tst testInput) {
 		opts := &ManagerOptions{
-			QueryFunc:       EngineQueryFunc(testEngine, storage),
+			QueryFunc:       EngineQueryFunc(ng, storage),
 			Appendable:      storage,
 			Queryable:       storage,
 			Context:         context.Background(),
@@ -1368,8 +1393,9 @@ func TestNativeHistogramsInRecordingRules(t *testing.T) {
 	}
 	require.NoError(t, app.Commit())
 
+	ng := testEngine(t)
 	opts := &ManagerOptions{
-		QueryFunc:  EngineQueryFunc(testEngine, storage),
+		QueryFunc:  EngineQueryFunc(ng, storage),
 		Appendable: storage,
 		Queryable:  storage,
 		Context:    context.Background(),

rules/recording_test.go

@@ -123,10 +123,11 @@ func TestRuleEval(t *testing.T) {
 	storage := setUpRuleEvalTest(t)
 	t.Cleanup(func() { storage.Close() })
 
+	ng := testEngine(t)
 	for _, scenario := range ruleEvalTestScenarios {
 		t.Run(scenario.name, func(t *testing.T) {
 			rule := NewRecordingRule("test_rule", scenario.expr, scenario.ruleLabels)
-			result, err := rule.Eval(context.TODO(), ruleEvaluationTime, EngineQueryFunc(testEngine, storage), nil, 0)
+			result, err := rule.Eval(context.TODO(), ruleEvaluationTime, EngineQueryFunc(ng, storage), nil, 0)
 			require.NoError(t, err)
 			testutil.RequireEqual(t, scenario.expected, result)
 		})
@@ -137,6 +138,7 @@ func BenchmarkRuleEval(b *testing.B) {
 	storage := setUpRuleEvalTest(b)
 	b.Cleanup(func() { storage.Close() })
 
+	ng := testEngine(b)
 	for _, scenario := range ruleEvalTestScenarios {
 		b.Run(scenario.name, func(b *testing.B) {
 			rule := NewRecordingRule("test_rule", scenario.expr, scenario.ruleLabels)
@@ -144,7 +146,7 @@ func BenchmarkRuleEval(b *testing.B) {
 			b.ResetTimer()
 
 			for i := 0; i < b.N; i++ {
-				_, err := rule.Eval(context.TODO(), ruleEvaluationTime, EngineQueryFunc(testEngine, storage), nil, 0)
+				_, err := rule.Eval(context.TODO(), ruleEvaluationTime, EngineQueryFunc(ng, storage), nil, 0)
 				if err != nil {
 					require.NoError(b, err)
 				}
@@ -166,6 +168,9 @@ func TestRuleEvalDuplicate(t *testing.T) {
 	}
 
 	engine := promql.NewEngine(opts)
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 	ctx, cancelCtx := context.WithCancel(context.Background())
 	defer cancelCtx()
 
@@ -212,10 +217,11 @@ func TestRecordingRuleLimit(t *testing.T) {
 		labels.FromStrings("test", "test"),
 	)
 
+	ng := testEngine(t)
 	evalTime := time.Unix(0, 0)
 
 	for _, test := range tests {
-		switch _, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(testEngine, storage), nil, test.limit); {
+		switch _, err := rule.Eval(context.TODO(), evalTime, EngineQueryFunc(ng, storage), nil, test.limit); {
 		case err != nil:
 			require.EqualError(t, err, test.err)
 		case test.err != "":

web/api/v1/api_test.go

@@ -59,7 +59,10 @@ import (
 	"github.com/prometheus/prometheus/util/teststorage"
 )
 
-var testEngine = promql.NewEngine(promql.EngineOpts{
+func testEngine(t *testing.T) *promql.Engine {
+	t.Helper()
+
+	ng := promql.NewEngine(promql.EngineOpts{
 		Logger:                   nil,
 		Reg:                      nil,
 		MaxSamples:               10000,
@@ -69,6 +72,12 @@ var testEngine = promql.NewEngine(promql.EngineOpts{
 		EnableNegativeOffset:     true,
 		EnablePerStepStats:       true,
 	})
+	t.Cleanup(func() {
+		require.NoError(t, ng.Close())
+	})
+
+	return ng
+}
 
 // testMetaStore satisfies the scrape.MetricMetadataStore interface.
 // It is used to inject specific metadata as part of a test case.
@@ -283,6 +292,9 @@ func (m *rulesRetrieverMock) CreateRuleGroups() {
 	}
 
 	engine := promql.NewEngine(engineOpts)
+	m.testing.Cleanup(func() {
+		require.NoError(m.testing, engine.Close())
+	})
 	opts := &rules.ManagerOptions{
 		QueryFunc:  rules.EngineQueryFunc(engine, storage),
 		Appendable: storage,
@@ -403,9 +415,10 @@ func TestEndpoints(t *testing.T) {
 
 	now := time.Now()
 
+	ng := testEngine(t)
+
 	t.Run("local", func(t *testing.T) {
-		algr := rulesRetrieverMock{}
-		algr.testing = t
+		algr := rulesRetrieverMock{testing: t}
 
 		algr.CreateAlertingRules()
 		algr.CreateRuleGroups()
@@ -417,7 +430,7 @@ func TestEndpoints(t *testing.T) {
 
 		api := &API{
 			Queryable:             storage,
-			QueryEngine:           testEngine,
+			QueryEngine:           ng,
 			ExemplarQueryable:     storage.ExemplarQueryable(),
 			targetRetriever:       testTargetRetriever.toFactory(),
 			alertmanagerRetriever: testAlertmanagerRetriever{}.toFactory(),
@@ -468,8 +481,7 @@ func TestEndpoints(t *testing.T) {
 		})
 		require.NoError(t, err)
 
-		algr := rulesRetrieverMock{}
-		algr.testing = t
+		algr := rulesRetrieverMock{testing: t}
 
 		algr.CreateAlertingRules()
 		algr.CreateRuleGroups()
@@ -481,7 +493,7 @@ func TestEndpoints(t *testing.T) {
 
 		api := &API{
 			Queryable:             remote,
-			QueryEngine:           testEngine,
+			QueryEngine:           ng,
 			ExemplarQueryable:     storage.ExemplarQueryable(),
 			targetRetriever:       testTargetRetriever.toFactory(),
 			alertmanagerRetriever: testAlertmanagerRetriever{}.toFactory(),
@@ -623,7 +635,7 @@ func TestQueryExemplars(t *testing.T) {
 
 	api := &API{
 		Queryable:         storage,
-		QueryEngine:       testEngine,
+		QueryEngine:       testEngine(t),
 		ExemplarQueryable: storage.ExemplarQueryable(),
 	}
 
@@ -831,7 +843,7 @@ func TestStats(t *testing.T) {
 
 	api := &API{
 		Queryable:   storage,
-		QueryEngine: testEngine,
+		QueryEngine: testEngine(t),
 		now: func() time.Time {
 			return time.Unix(123, 0)
 		},

web/api/v1/errors_test.go

@@ -86,7 +86,7 @@ func TestApiStatusCodes(t *testing.T) {
 			"error from seriesset": errorTestQueryable{q: errorTestQuerier{s: errorTestSeriesSet{err: tc.err}}},
 		} {
 			t.Run(fmt.Sprintf("%s/%s", name, k), func(t *testing.T) {
-				r := createPrometheusAPI(q)
+				r := createPrometheusAPI(t, q)
 				rec := httptest.NewRecorder()
 
 				req := httptest.NewRequest(http.MethodGet, "/api/v1/query?query=up", nil)
@@ -100,7 +100,9 @@ func TestApiStatusCodes(t *testing.T) {
 	}
 }
 
-func createPrometheusAPI(q storage.SampleAndChunkQueryable) *route.Router {
+func createPrometheusAPI(t *testing.T, q storage.SampleAndChunkQueryable) *route.Router {
+	t.Helper()
+
 	engine := promql.NewEngine(promql.EngineOpts{
 		Logger:             log.NewNopLogger(),
 		Reg:                nil,
@@ -108,6 +110,9 @@ func createPrometheusAPI(q storage.SampleAndChunkQueryable) *route.Router {
 		MaxSamples:         100,
 		Timeout:            5 * time.Second,
 	})
+	t.Cleanup(func() {
+		require.NoError(t, engine.Close())
+	})
 
 	api := NewAPI(
 		engine,