feast-dev
diff --git a/go.mod b/go.mod
@@ -11,12 +11,15 @@ require (
 	github.com/aws/aws-sdk-go-v2/config v1.29.14
 	github.com/aws/aws-sdk-go-v2/service/dynamodb v1.43.3
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.79.3
+	github.com/cabify/gotoprom v1.1.0
 	github.com/ghodss/yaml v1.0.0
 	github.com/go-sql-driver/mysql v1.8.1
 	github.com/golang/protobuf v1.5.4
 	github.com/google/uuid v1.6.0
+	github.com/grpc-ecosystem/go-grpc-middleware/providers/prometheus v1.1.0
 	github.com/mattn/go-sqlite3 v1.14.23
 	github.com/pkg/errors v0.9.1
+	github.com/prometheus/client_golang v1.23.2
 	github.com/redis/go-redis/v9 v9.6.1
 	github.com/roberson-io/mmh3 v0.0.0-20190729202758-fdfce3ba6225
 	github.com/rs/zerolog v1.33.0
@@ -64,6 +67,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.30.1 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sts v1.33.19 // indirect
 	github.com/aws/smithy-go v1.22.2 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cncf/xds/go v0.0.0-20250501225837-2ac532fd4443 // indirect
@@ -81,6 +85,7 @@ require (
 	github.com/google/s2a-go v0.1.9 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.7 // indirect
 	github.com/googleapis/gax-go/v2 v2.15.0 // indirect
+	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.1.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
@@ -93,9 +98,13 @@ require (
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/minio/asm2plan9s v0.0.0-20200509001527-cdd76441f9d8 // indirect
 	github.com/minio/c2goasm v0.0.0-20190812172519-36a3d3bbc4f3 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pierrec/lz4/v4 v4.1.21 // indirect
 	github.com/planetscale/vtprotobuf v0.6.1-0.20240319094008-0393e58bdf10 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/prometheus/client_model v0.6.2 // indirect
+	github.com/prometheus/common v0.66.1 // indirect
+	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/spiffe/go-spiffe/v2 v2.5.0 // indirect
 	github.com/stretchr/objx v0.5.2 // indirect
 	github.com/zeebo/errs v1.4.0 // indirect
@@ -107,6 +116,7 @@ require (
 	go.opentelemetry.io/otel/metric v1.38.0 // indirect
 	go.opentelemetry.io/otel/sdk/metric v1.38.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.7.1 // indirect
+	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/crypto v0.45.0 // indirect
 	golang.org/x/exp v0.0.0-20240909161429-701f63a606c0 // indirect
 	golang.org/x/mod v0.29.0 // indirect

diff --git a/go.sum b/go.sum
@@ -6,14 +6,27 @@ To build and run the Go Feature Server locally, create a feature_store.yaml file
 
 ```bash
     go build -o feast-go ./go/main.go
-    # start the http server
-    ./feast-go --type=http --port=8080
+    # start the http server (metrics on port 9090 by default)
+    ./feast-go --type=http --port=8080 --metrics-port=9090
     # or start the gRPC server
-    #./feast-go --type=grpc  --port=[your-choice]
+    #./feast-go --type=grpc  --port=[your-choice] --metrics-port=9091
 ```
+## Prometheus Metrics
+The server exposes Prometheus metrics at the `/metrics` endpoint on a dedicated port (default `:9090`).
+- **HTTP Mode**: Metrics server runs on port `9090` (configurable via `-metrics-port`).
+- **gRPC Mode**: Metrics server runs on port `9090` (configurable via `-metrics-port`).
+
+Key metrics include:
+- `http_request_duration_seconds`: Histogram of response latency.
+- `http_requests_total`: Counter of HTTP requests by status, method, and path.
+- Standard Go and Process metrics.
+
+A `/health` endpoint is available on the main application port (default `:8080`) for readiness probes.
+
 
 ## OTEL based observability
 The OS level env variable `ENABLE_OTEL_TRACING=="true"/"false"` (string type) is used to enable/disable this service (with Tracing only).
+You can also configure the service name using `OTEL_SERVICE_NAME` env variable (defaults to "FeastGoFeatureServer").
 
 The default exporter URL is "http://localhost:4318". The default schema of sending data to collector is **HTTP**. Please refer the following two docs about the configuration of the OTEL exporter:  
 1. https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/  

@@ -0,0 +1,66 @@
+package metrics
+
+import (
+	"reflect"
+	"time"
+
+	"github.com/cabify/gotoprom"
+	"github.com/cabify/gotoprom/prometheusvanilla"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var HttpMetrics struct {
+	Duration func(HttpLabels) TimeHistogram `name:"http_request_duration_seconds" help:"Time taken to serve HTTP requests" buckets:".005,.01,.025,.05,.1,.25,.5,1,2.5,5,10"`
+
+	RequestsTotal func(HttpLabels) prometheus.Counter `name:"http_requests_total" help:"Total number of HTTP requests"`
+}
+
+type HttpLabels struct {
+	Method string `label:"method"`
+	Status int    `label:"status"`
+	Path   string `label:"path"`
+}
+
+func init() {
+	gotoprom.MustAddBuilder(TimeHistogramType, RegisterTimeHistogram)
+	gotoprom.MustInit(&HttpMetrics, "feast")
+}
+
+var (
+	TimeHistogramType = reflect.TypeOf((*TimeHistogram)(nil)).Elem()
+)
+
+
+func RegisterTimeHistogram(name, help, namespace string, labelNames []string, tag reflect.StructTag) (func(prometheus.Labels) interface{}, prometheus.Collector, error) {
+	f, collector, err := prometheusvanilla.BuildHistogram(name, help, namespace, labelNames, tag)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return func(labels prometheus.Labels) interface{} {
+		return timeHistogramAdapter{Histogram: f(labels).(prometheus.Histogram)}
+	}, collector, nil
+}
+
+// TimeHistogram offers the basic prometheus.Histogram functionality
+type TimeHistogram interface {
+	prometheus.Histogram
+	// Duration observes the duration in seconds
+	Duration(duration time.Duration)
+	// Since observes the duration in seconds since the time point provided
+	Since(time.Time)
+}
+
+type timeHistogramAdapter struct {
+	prometheus.Histogram
+}
+
+// Duration observes the duration in seconds
+func (to timeHistogramAdapter) Duration(duration time.Duration) {
+	to.Observe(duration.Seconds())
+}
+
+// Since observes the duration in seconds since the time point provided
+func (to timeHistogramAdapter) Since(duration time.Time) {
+	to.Duration(time.Since(duration))
+}
@@ -17,6 +17,8 @@ import (
 	prototypes "github.com/feast-dev/feast/go/protos/feast/types"
 	"github.com/feast-dev/feast/go/types"
 	"github.com/rs/zerolog/log"
+
+	"github.com/feast-dev/feast/go/internal/feast/metrics"
 )
 
 type httpServer struct {
@@ -335,10 +337,55 @@ func recoverMiddleware(next http.Handler) http.Handler {
 	})
 }
 
+type statusWriter struct {
+	http.ResponseWriter
+	status int
+}
+
+func (w *statusWriter) WriteHeader(status int) {
+	if w.status == 0 {
+		w.status = status
+	}
+	w.ResponseWriter.WriteHeader(status)
+}
+
+func (w *statusWriter) Write(b []byte) (int, error) {
+	if w.status == 0 {
+		w.status = 200
+	}
+	n, err := w.ResponseWriter.Write(b)
+	return n, err
+}
+
+func metricsMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t0 := time.Now()
+		sw := &statusWriter{ResponseWriter: w}
+		next.ServeHTTP(sw, r)
+		duration := time.Since(t0)
+
+		if sw.status == 0 {
+			sw.status = 200
+		}
+
+		metrics.HttpMetrics.Duration(metrics.HttpLabels{
+			Method: r.Method,
+			Status: sw.status,
+			Path:   r.URL.Path,
+		}).Duration(duration)
+
+		metrics.HttpMetrics.RequestsTotal(metrics.HttpLabels{
+			Method: r.Method,
+			Status: sw.status,
+			Path:   r.URL.Path,
+		}).Inc()
+	})
+}
+
 func (s *httpServer) Serve(host string, port int) error {
 	mux := http.NewServeMux()
-	mux.Handle("/get-online-features", recoverMiddleware(http.HandlerFunc(s.getOnlineFeatures)))
-	mux.HandleFunc("/health", healthCheckHandler)
+	mux.Handle("/get-online-features", metricsMiddleware(recoverMiddleware(http.HandlerFunc(s.getOnlineFeatures))))
+	mux.Handle("/health", metricsMiddleware(http.HandlerFunc(healthCheckHandler)))
 	s.server = &http.Server{Addr: fmt.Sprintf("%s:%d", host, port), Handler: mux, ReadTimeout: 5 * time.Second, WriteTimeout: 10 * time.Second, IdleTimeout: 15 * time.Second}
 	err := s.server.ListenAndServe()
 	// Don't return the error if it's caused by graceful shutdown using Stop()