feat: Add http endpoint to the Go feature server

go/embedded/online_features.go

@@ -31,6 +31,7 @@ import (
 type OnlineFeatureService struct {
 	fs         *feast.FeatureStore
 	grpcStopCh chan os.Signal
+	httpStopCh chan os.Signal
 }
 
 type OnlineFeatureServiceConfig struct {
@@ -63,11 +64,13 @@ func NewOnlineFeatureService(conf *OnlineFeatureServiceConfig, transformationCal
 		log.Fatalln(err)
 	}
 
-	// Notify this channel when receiving interrupt or termination signals from OS
-	c := make(chan os.Signal, 1)
-	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+	// Notify these channels when receiving interrupt or termination signals from OS
+	httpStopCh := make(chan os.Signal, 1)
+	grpcStopCh := make(chan os.Signal, 1)
+	signal.Notify(httpStopCh, syscall.SIGINT, syscall.SIGTERM)
+	signal.Notify(grpcStopCh, syscall.SIGINT, syscall.SIGTERM)
 
-	return &OnlineFeatureService{fs: fs, grpcStopCh: c}
+	return &OnlineFeatureService{fs: fs, httpStopCh: httpStopCh, grpcStopCh: grpcStopCh}
 }
 
 func (s *OnlineFeatureService) GetEntityTypesMap(featureRefs []string) (map[string]int32, error) {
@@ -239,15 +242,12 @@ func (s *OnlineFeatureService) StartGprcServerWithLoggingDefaultOpts(host string
 	return s.StartGprcServerWithLogging(host, port, writeLoggedFeaturesCallback, defaultOpts)
 }
 
-// StartGprcServerWithLogging starts gRPC server with enabled feature logging
-// Caller of this function must provide Python callback to flush buffered logs as well as logging configuration (loggingOpts)
-func (s *OnlineFeatureService) StartGprcServerWithLogging(host string, port int, writeLoggedFeaturesCallback logging.OfflineStoreWriteCallback, loggingOpts LoggingOptions) error {
+func (s *OnlineFeatureService) constructLoggingService(writeLoggedFeaturesCallback logging.OfflineStoreWriteCallback, loggingOpts LoggingOptions) (*logging.LoggingService, error) {
 	var loggingService *logging.LoggingService = nil
-	var err error
 	if writeLoggedFeaturesCallback != nil {
 		sink, err := logging.NewOfflineStoreSink(writeLoggedFeaturesCallback)
 		if err != nil {
-			return err
+			return nil, err
 		}
 
 		loggingService, err = logging.NewLoggingService(s.fs, sink, logging.LoggingOptions{
@@ -257,9 +257,19 @@ func (s *OnlineFeatureService) StartGprcServerWithLogging(host string, port int,
 			FlushInterval:   loggingOpts.FlushInterval,
 		})
 		if err != nil {
-			return err
+			return nil, err
 		}
 	}
+	return loggingService, nil
+}
+
+// StartGprcServerWithLogging starts gRPC server with enabled feature logging
+// Caller of this function must provide Python callback to flush buffered logs as well as logging configuration (loggingOpts)
+func (s *OnlineFeatureService) StartGprcServerWithLogging(host string, port int, writeLoggedFeaturesCallback logging.OfflineStoreWriteCallback, loggingOpts LoggingOptions) error {
+	loggingService, err := s.constructLoggingService(writeLoggedFeaturesCallback, loggingOpts)
+	if err != nil {
+		return err
+	}
 	ser := server.NewGrpcServingServiceServer(s.fs, loggingService)
 	log.Printf("Starting a gRPC server on host %s port %d\n", host, port)
 	lis, err := net.Listen("tcp", fmt.Sprintf("%s:%d", host, port))
@@ -288,7 +298,51 @@ func (s *OnlineFeatureService) StartGprcServerWithLogging(host string, port int,
 	return nil
 }
 
-func (s *OnlineFeatureService) Stop() {
+// StartHttpServer starts HTTP server with disabled feature logging and blocks the thread
+func (s *OnlineFeatureService) StartHttpServer(host string, port int) error {
+	return s.StartHttpServerWithLogging(host, port, nil, LoggingOptions{})
+}
+
+// StartHttpServerWithLoggingDefaultOpts starts HTTP server with enabled feature logging but default configuration for logging
+// Caller of this function must provide Python callback to flush buffered logs
+func (s *OnlineFeatureService) StartHttpServerWithLoggingDefaultOpts(host string, port int, writeLoggedFeaturesCallback logging.OfflineStoreWriteCallback) error {
+	defaultOpts := LoggingOptions{
+		ChannelCapacity: logging.DefaultOptions.ChannelCapacity,
+		EmitTimeout:     logging.DefaultOptions.EmitTimeout,
+		WriteInterval:   logging.DefaultOptions.WriteInterval,
+		FlushInterval:   logging.DefaultOptions.FlushInterval,
+	}
+	return s.StartHttpServerWithLogging(host, port, writeLoggedFeaturesCallback, defaultOpts)
+}
+
+// StartHttpServerWithLogging starts HTTP server with enabled feature logging
+// Caller of this function must provide Python callback to flush buffered logs as well as logging configuration (loggingOpts)
+func (s *OnlineFeatureService) StartHttpServerWithLogging(host string, port int, writeLoggedFeaturesCallback logging.OfflineStoreWriteCallback, loggingOpts LoggingOptions) error {
+	loggingService, err := s.constructLoggingService(writeLoggedFeaturesCallback, loggingOpts)
+	if err != nil {
+		return err
+	}
+	ser := server.NewHttpServer(s.fs, loggingService)
+	log.Printf("Starting a HTTP server on host %s port %d\n", host, port)
+
+	go func() {
+		// As soon as these signals are received from OS, try to gracefully stop the gRPC server
+		<-s.httpStopCh
+		fmt.Println("Stopping the HTTP server...")
+		err := ser.Stop()
+		if err != nil {
+			fmt.Printf("Error when stopping the HTTP server: %v\n", err)
+		}
+	}()
+
+	return ser.Serve(host, port)
+}
+
+func (s *OnlineFeatureService) StopHttpServer() {
+	s.httpStopCh <- syscall.SIGINT
+}
+
+func (s *OnlineFeatureService) StopGrpcServer() {
 	s.grpcStopCh <- syscall.SIGINT
 }
 

go/internal/feast/server/grpc_server.go

@@ -86,7 +86,7 @@ func (s *grpcServingServiceServer) GetOnlineFeatures(ctx context.Context, reques
 			fmt.Printf("Couldn't instantiate logger for feature service %s: %+v", featuresOrService.FeatureService.Name, err)
 		}
 
-		err = logger.Log(entityValuesMap, resp.Results[len(request.Entities):], resp.Metadata.FeatureNames.Val[len(request.Entities):], request.RequestContext, requestId)
+		err = logger.Log(request.Entities, resp.Results[len(request.Entities):], resp.Metadata.FeatureNames.Val[len(request.Entities):], request.RequestContext, requestId)
 		if err != nil {
 			fmt.Printf("LoggerImpl error[%s]: %+v", featuresOrService.FeatureService.Name, err)
 		}

go/internal/feast/server/http_server.go

@@ -0,0 +1,270 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/feast-dev/feast/go/internal/feast"
+	"github.com/feast-dev/feast/go/internal/feast/model"
+	"github.com/feast-dev/feast/go/internal/feast/server/logging"
+	"github.com/feast-dev/feast/go/protos/feast/serving"
+	prototypes "github.com/feast-dev/feast/go/protos/feast/types"
+	"github.com/feast-dev/feast/go/types"
+	"net/http"
+	"time"
+)
+
+type httpServer struct {
+	fs             *feast.FeatureStore
+	loggingService *logging.LoggingService
+	server         *http.Server
+}
+
+// Some Feast types aren't supported during JSON conversion
+type repeatedValue struct {
+	stringVal     []string
+	int64Val      []int64
+	doubleVal     []float64
+	boolVal       []bool
+	stringListVal [][]string
+	int64ListVal  [][]int64
+	doubleListVal [][]float64
+	boolListVal   [][]bool
+}
+
+func (u *repeatedValue) UnmarshalJSON(data []byte) error {
+	isString := false
+	isDouble := false
+	isInt64 := false
+	isArray := false
+	openBraketCounter := 0
+	for _, b := range data {
+		if b == '"' {
+			isString = true
+		}
+		if b == '.' {
+			isDouble = true
+		}
+		if b >= '0' && b <= '9' {
+			isInt64 = true
+		}
+		if b == '[' {
+			openBraketCounter++
+			if openBraketCounter > 1 {
+				isArray = true
+			}
+		}
+	}
+	var err error
+	if !isArray {
+		if isString {
+			err = json.Unmarshal(data, &u.stringVal)
+		} else if isDouble {
+			err = json.Unmarshal(data, &u.doubleVal)
+		} else if isInt64 {
+			err = json.Unmarshal(data, &u.int64Val)
+		} else {
+			err = json.Unmarshal(data, &u.boolVal)
+		}
+	} else {
+		if isString {
+			err = json.Unmarshal(data, &u.stringListVal)
+		} else if isDouble {
+			err = json.Unmarshal(data, &u.doubleListVal)
+		} else if isInt64 {
+			err = json.Unmarshal(data, &u.int64ListVal)
+		} else {
+			err = json.Unmarshal(data, &u.boolListVal)
+		}
+	}
+	return err
+}
+
+func (u *repeatedValue) ToProto() *prototypes.RepeatedValue {
+	proto := new(prototypes.RepeatedValue)
+	if u.stringVal != nil {
+		for _, val := range u.stringVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_StringVal{StringVal: val}})
+		}
+	}
+	if u.int64Val != nil {
+		for _, val := range u.int64Val {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_Int64Val{Int64Val: val}})
+		}
+	}
+	if u.doubleVal != nil {
+		for _, val := range u.doubleVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_DoubleVal{DoubleVal: val}})
+		}
+	}
+	if u.boolVal != nil {
+		for _, val := range u.boolVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_BoolVal{BoolVal: val}})
+		}
+	}
+	if u.stringListVal != nil {
+		for _, val := range u.stringListVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_StringListVal{StringListVal: &prototypes.StringList{Val: val}}})
+		}
+	}
+	if u.int64ListVal != nil {
+		for _, val := range u.int64ListVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_Int64ListVal{Int64ListVal: &prototypes.Int64List{Val: val}}})
+		}
+	}
+	if u.doubleListVal != nil {
+		for _, val := range u.doubleListVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_DoubleListVal{DoubleListVal: &prototypes.DoubleList{Val: val}}})
+		}
+	}
+	if u.boolListVal != nil {
+		for _, val := range u.boolListVal {
+			proto.Val = append(proto.Val, &prototypes.Value{Val: &prototypes.Value_BoolListVal{BoolListVal: &prototypes.BoolList{Val: val}}})
+		}
+	}
+	return proto
+}
+
+type getOnlineFeaturesRequest struct {
+	FeatureService   *string                  `json:"feature_service"`
+	Features         []string                 `json:"features"`
+	Entities         map[string]repeatedValue `json:"entities"`
+	FullFeatureNames bool                     `json:"full_feature_names"`
+	RequestContext   map[string]repeatedValue `json:"request_context"`
+}
+
+func NewHttpServer(fs *feast.FeatureStore, loggingService *logging.LoggingService) *httpServer {
+	return &httpServer{fs: fs, loggingService: loggingService}
+}
+
+func (s *httpServer) getOnlineFeatures(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		http.NotFound(w, r)
+		return
+	}
+
+	decoder := json.NewDecoder(r.Body)
+	var request getOnlineFeaturesRequest
+	err := decoder.Decode(&request)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Error decoding JSON request data: %+v", err), http.StatusInternalServerError)
+		return
+	}
+	var featureService *model.FeatureService
+	if request.FeatureService != nil {
+		featureService, err = s.fs.GetFeatureService(*request.FeatureService)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("Error getting feature service from registry: %+v", err), http.StatusInternalServerError)
+			return
+		}
+	}
+	entitiesProto := make(map[string]*prototypes.RepeatedValue)
+	for key, value := range request.Entities {
+		entitiesProto[key] = value.ToProto()
+	}
+	requestContextProto := make(map[string]*prototypes.RepeatedValue)
+	for key, value := range request.RequestContext {
+		requestContextProto[key] = value.ToProto()
+	}
+
+	featureVectors, err := s.fs.GetOnlineFeatures(
+		r.Context(),
+		request.Features,
+		featureService,
+		entitiesProto,
+		requestContextProto,
+		request.FullFeatureNames)
+
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Error getting feature vector: %+v", err), http.StatusInternalServerError)
+		return
+	}
+
+	var featureNames []string
+	var results []map[string]interface{}
+	for _, vector := range featureVectors {
+		featureNames = append(featureNames, vector.Name)
+		result := make(map[string]interface{})
+		var statuses []string
+		for _, status := range vector.Statuses {
+			statuses = append(statuses, status.String())
+		}
+		var timestamps []string
+		for _, timestamp := range vector.Timestamps {
+			timestamps = append(timestamps, timestamp.AsTime().Format(time.RFC3339))
+		}
+
+		result["statuses"] = statuses
+		result["event_timestamps"] = timestamps
+		// Note, that vector.Values is an Arrow Array, but this type implements JSON Marshaller.
+		// So, it's not necessary to pre-process it in any way.
+		result["values"] = vector.Values
+
+		results = append(results, result)
+	}
+
+	response := map[string]interface{}{
+		"metadata": map[string]interface{}{
+			"feature_names": featureNames,
+		},
+		"results": results,
+	}
+
+	err = json.NewEncoder(w).Encode(response)
+
+	if err != nil {
+		http.Error(w, fmt.Sprintf("Error encoding response: %+v", err), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+
+	if featureService != nil && featureService.LoggingConfig != nil && s.loggingService != nil {
+		logger, err := s.loggingService.GetOrCreateLogger(featureService)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("Couldn't instantiate logger for feature service %s: %+v", featureService.Name, err), http.StatusInternalServerError)
+			return
+		}
+
+		requestId := GenerateRequestId()
+
+		// Note: we're converting arrow to proto for feature logging. In the future we should
+		// base feature logging on arrow so that we don't have to do this extra conversion.
+		var featureVectorProtos []*serving.GetOnlineFeaturesResponse_FeatureVector
+		for _, vector := range featureVectors[len(request.Entities):] {
+			values, err := types.ArrowValuesToProtoValues(vector.Values)
+			if err != nil {
+				http.Error(w, fmt.Sprintf("Couldn't convert arrow values into protobuf: %+v", err), http.StatusInternalServerError)
+				return
+			}
+			featureVectorProtos = append(featureVectorProtos, &serving.GetOnlineFeaturesResponse_FeatureVector{
+				Values:          values,
+				Statuses:        vector.Statuses,
+				EventTimestamps: vector.Timestamps,
+			})
+		}
+
+		err = logger.Log(entitiesProto, featureVectorProtos, featureNames[len(request.Entities):], requestContextProto, requestId)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("LoggerImpl error[%s]: %+v", featureService.Name, err), http.StatusInternalServerError)
+			return
+		}
+	}
+}
+
+func (s *httpServer) Serve(host string, port int) error {
+	s.server = &http.Server{Addr: fmt.Sprintf("%s:%d", host, port), Handler: nil}
+	http.HandleFunc("/get-online-features", s.getOnlineFeatures)
+	err := s.server.ListenAndServe()
+	// Don't return the error if it's caused by graceful shutdown using Stop()
+	if err == http.ErrServerClosed {
+		return nil
+	}
+	return err
+}
+func (s *httpServer) Stop() error {
+	if s.server != nil {
+		return s.server.Shutdown(context.Background())
+	}
+	return nil
+}