fix: gateway_s3_bytes_sent metric for all API methods (#9242)

Co-authored-by: Harshavardhana <harsha@minio.io>

cmd/gateway-common.go

@@ -432,7 +432,7 @@ type MetricsTransport struct {
 // RoundTrip implements the RoundTrip method for MetricsTransport
 func (m MetricsTransport) RoundTrip(r *http.Request) (*http.Response, error) {
 	metered := shouldMeterRequest(r)
-	if metered && (r.Method == http.MethodGet || r.Method == http.MethodHead) {
+	if metered && (r.Method == http.MethodPost || r.Method == http.MethodPut) {
 		m.Metrics.IncRequests(r.Method)
 		if r.ContentLength > 0 {
 			m.Metrics.IncBytesSent(uint64(r.ContentLength))
@@ -444,7 +444,8 @@ func (m MetricsTransport) RoundTrip(r *http.Request) (*http.Response, error) {
 		return nil, err
 	}
 	if metered && (r.Method == http.MethodGet || r.Method == http.MethodHead) {
-		if r.ContentLength > 0 {
+		m.Metrics.IncRequests(r.Method)
+		if resp.ContentLength > 0 {
 			m.Metrics.IncBytesReceived(uint64(resp.ContentLength))
 		}
 	}

cmd/gateway-metrics.go

@@ -26,6 +26,8 @@ import (
 type RequestStats struct {
 	Get  atomic.Uint64 `json:"Get"`
 	Head atomic.Uint64 `json:"Head"`
+	Put  atomic.Uint64 `json:"Put"`
+	Post atomic.Uint64 `json:"Post"`
 }
 
 // Metrics - represents bytes served from backend
@@ -63,6 +65,10 @@ func (s *Metrics) IncRequests(method string) {
 		s.requestStats.Get.Add(1)
 	} else if method == http.MethodHead {
 		s.requestStats.Head.Add(1)
+	} else if method == http.MethodPut {
+		s.requestStats.Put.Add(1)
+	} else if method == http.MethodPost {
+		s.requestStats.Post.Add(1)
 	}
 }
 

cmd/metrics.go

@@ -203,6 +203,24 @@ func gatewayMetricsPrometheus(ch chan<- prometheus.Metric) {
 		float64(s.Head.Load()),
 		http.MethodHead,
 	)
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName("gateway", globalGatewayName, "requests"),
+			"Total number of requests made to "+globalGatewayName+" by current MinIO Gateway",
+			[]string{"method"}, nil),
+		prometheus.CounterValue,
+		float64(s.Put.Load()),
+		http.MethodPut,
+	)
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName("gateway", globalGatewayName, "requests"),
+			"Total number of requests made to "+globalGatewayName+" by current MinIO Gateway",
+			[]string{"method"}, nil),
+		prometheus.CounterValue,
+		float64(s.Post.Load()),
+		http.MethodPost,
+	)
 }
 
 // collects cache metrics for MinIO server in Prometheus specific format

docs/metrics/prometheus/README.md

@@ -151,8 +151,8 @@ MinIO Gateway instances enabled with Disk-Caching expose caching related metrics
 
 MinIO Gateway instance exposes metrics related to Gateway communication with the cloud backend (S3, Azure & GCS Gateway).
 
-- `gateway_<gateway_type>_requests`: Total number of GET & HEAD requests made to cloud backend. This metrics has a label `method` that identifies GET & HEAD Requests.
-- `gateway_<gateway_type>_bytes_sent`: Total number of bytes sent to cloud backend (in GET & HEAD Requests).
+- `gateway_<gateway_type>_requests`: Total number of requests made to cloud backend. This metrics has a label `method` that identifies GET, HEAD, PUT and POST Requests.
+- `gateway_<gateway_type>_bytes_sent`: Total number of bytes sent to cloud backend (in PUT & POST Requests).
 - `gateway_<gateway_type>_bytes_received`: Total number of bytes received from cloud backend (in GET & HEAD Requests).
 
 Note that this is currently only support for Azure, S3 and GCS Gateway.