api: fix race between Respond() and query/queryRange

Fix a data race between Respond() and query/queryRange functions by returning an extra optional function from instrumented functions that releases the resources i.e. calls Close(). Cannot reproduce the following race: ``` ================== WARNING: DATA RACE Write at 0x00c00566fa00 by goroutine 562: github.com/prometheus/prometheus/promql.(*evaluator).eval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:1450 +0x8044 github.com/prometheus/prometheus/promql.(*evaluator).rangeEval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:1060 +0x2684 github.com/prometheus/prometheus/promql.(*evaluator).eval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:1281 +0x42a4 github.com/prometheus/prometheus/promql.(*evaluator).rangeEval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:1060 +0x2684 github.com/prometheus/prometheus/promql.(*evaluator).eval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:1281 +0x42a4 github.com/prometheus/prometheus/promql.(*evaluator).Eval() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:989 +0xf5 github.com/prometheus/prometheus/promql.(*Engine).execEvalStmt() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:645 +0xa77 github.com/prometheus/prometheus/promql.(*Engine).exec() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:595 +0x71e github.com/prometheus/prometheus/promql.(*query).Exec() /home/giedrius/go/pkg/mod/github.com/vinted/prometheus@v1.8.2-0.20220808145920-5c879a061105/promql/engine.go:197 +0x250 github.com/thanos-io/thanos/pkg/api/query.(*QueryAPI).query() /home/giedrius/dev/thanos/pkg/api/query/v1.go:387 +0xbf2 github.com/thanos-io/thanos/pkg/api/query.(*QueryAPI).query-fm() ... Previous read at 0x00c00566fa00 by goroutine 570: github.com/prometheus/prometheus/promql.(*Point).MarshalJSON() <autogenerated>:1 +0x4e encoding/json.addrMarshalerEncoder() /usr/lib/go-1.19/src/encoding/json/encode.go:495 +0x1af encoding/json.condAddrEncoder.encode() /usr/lib/go-1.19/src/encoding/json/encode.go:959 +0x94 encoding/json.condAddrEncoder.encode-fm() <autogenerated>:1 +0xa4 encoding/json.arrayEncoder.encode() /usr/lib/go-1.19/src/encoding/json/encode.go:915 +0x10e encoding/json.arrayEncoder.encode-fm() <autogenerated>:1 +0x90 encoding/json.sliceEncoder.encode() ``` Should fix thanos-io#5501. Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
GiedriusS · Aug 10, 2022 · 2cedf6a · 2cedf6a
1 parent 6d1b98d
commit 2cedf6a
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Showing 7 changed files with 132 additions and 128 deletions.
diff --git a/pkg/api/api.go b/pkg/api/api.go
@@ -121,7 +121,7 @@ func SetCORS(w http.ResponseWriter) {
 	}
 }
 
-type ApiFunc func(r *http.Request) (interface{}, []error, *ApiError)
+type ApiFunc func(r *http.Request) (interface{}, []error, *ApiError, func())
 
 type BaseAPI struct {
 	logger      log.Logger
@@ -156,20 +156,20 @@ func (api *BaseAPI) Register(r *route.Router, tracer opentracing.Tracer, logger
 	r.Get("/status/buildinfo", instr("status_build", api.serveBuildInfo))
 }
 
-func (api *BaseAPI) options(r *http.Request) (interface{}, []error, *ApiError) {
-	return nil, nil, nil
+func (api *BaseAPI) options(r *http.Request) (interface{}, []error, *ApiError, func()) {
+	return nil, nil, nil, func() {}
 }
 
-func (api *BaseAPI) flags(r *http.Request) (interface{}, []error, *ApiError) {
-	return api.flagsMap, nil, nil
+func (api *BaseAPI) flags(r *http.Request) (interface{}, []error, *ApiError, func()) {
+	return api.flagsMap, nil, nil, func() {}
 }
 
-func (api *BaseAPI) serveRuntimeInfo(r *http.Request) (interface{}, []error, *ApiError) {
-	return api.runtimeInfo(), nil, nil
+func (api *BaseAPI) serveRuntimeInfo(r *http.Request) (interface{}, []error, *ApiError, func()) {
+	return api.runtimeInfo(), nil, nil, func() {}
 }
 
-func (api *BaseAPI) serveBuildInfo(r *http.Request) (interface{}, []error, *ApiError) {
-	return api.buildInfo, nil, nil
+func (api *BaseAPI) serveBuildInfo(r *http.Request) (interface{}, []error, *ApiError, func()) {
+	return api.buildInfo, nil, nil, func() {}
 }
 
 func GetRuntimeInfoFunc(logger log.Logger) RuntimeInfoFn {
@@ -208,12 +208,15 @@ func GetInstr(
 			if !disableCORS {
 				SetCORS(w)
 			}
-			if data, warnings, err := f(r); err != nil {
+			if data, warnings, err, releaseResources := f(r); err != nil {
 				RespondError(w, err, data)
+				releaseResources()
 			} else if data != nil {
 				Respond(w, data, warnings)
+				releaseResources()
 			} else {
 				w.WriteHeader(http.StatusNoContent)
+				releaseResources()
 			}
 		})
 

diff --git a/pkg/api/blocks/v1.go b/pkg/api/blocks/v1.go
@@ -86,48 +86,48 @@ func (bapi *BlocksAPI) Register(r *route.Router, tracer opentracing.Tracer, logg
 	r.Post("/blocks/mark", instr("blocks_mark", bapi.markBlock))
 }
 
-func (bapi *BlocksAPI) markBlock(r *http.Request) (interface{}, []error, *api.ApiError) {
+func (bapi *BlocksAPI) markBlock(r *http.Request) (interface{}, []error, *api.ApiError, func()) {
 	idParam := r.FormValue("id")
 	actionParam := r.FormValue("action")
 	detailParam := r.FormValue("detail")
 
 	if idParam == "" {
-		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.New("ID cannot be empty")}
+		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.New("ID cannot be empty")}, func() {}
 	}
 
 	if actionParam == "" {
-		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.New("Action cannot be empty")}
+		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.New("Action cannot be empty")}, func() {}
 	}
 
 	id, err := ulid.Parse(idParam)
 	if err != nil {
-		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.Errorf("ULID %q is not valid: %v", idParam, err)}
+		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.Errorf("ULID %q is not valid: %v", idParam, err)}, func() {}
 	}
 
 	actionType := parse(actionParam)
 	switch actionType {
 	case Deletion:
 		err := block.MarkForDeletion(r.Context(), bapi.logger, bapi.bkt, id, detailParam, promauto.With(nil).NewCounter(prometheus.CounterOpts{}))
 		if err != nil {
-			return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
+			return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}, func() {}
 		}
 	case NoCompaction:
 		err := block.MarkForNoCompact(r.Context(), bapi.logger, bapi.bkt, id, metadata.ManualNoCompactReason, detailParam, promauto.With(nil).NewCounter(prometheus.CounterOpts{}))
 		if err != nil {
-			return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
+			return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}, func() {}
 		}
 	default:
-		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.Errorf("not supported marker %v", actionParam)}
+		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.Errorf("not supported marker %v", actionParam)}, func() {}
 	}
-	return nil, nil, nil
+	return nil, nil, nil, func() {}
 }
 
-func (bapi *BlocksAPI) blocks(r *http.Request) (interface{}, []error, *api.ApiError) {
+func (bapi *BlocksAPI) blocks(r *http.Request) (interface{}, []error, *api.ApiError, func()) {
 	viewParam := r.URL.Query().Get("view")
 	if viewParam == "loaded" {
-		return bapi.loadedBlocksInfo, nil, nil
+		return bapi.loadedBlocksInfo, nil, nil, func() {}
 	}
-	return bapi.globalBlocksInfo, nil, nil
+	return bapi.globalBlocksInfo, nil, nil, func() {}
 }
 
 func (b *BlocksInfo) set(blocks []metadata.Meta, err error) {

diff --git a/pkg/api/blocks/v1_test.go b/pkg/api/blocks/v1_test.go
@@ -71,7 +71,8 @@ func testEndpoint(t *testing.T, test endpointTestCase, name string, responseComp
 			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 		}
 
-		resp, _, apiErr := test.endpoint(req.WithContext(ctx))
+		resp, _, apiErr, releaseResources := test.endpoint(req.WithContext(ctx))
+		defer releaseResources()
 		if apiErr != nil {
 			if test.errType == baseAPI.ErrorNone {
 				t.Fatalf("Unexpected error: %s", apiErr)