metrics: Add canceled requests (#11881)

Add metric for canceled requests

cmd/admin-handlers.go

@@ -263,6 +263,7 @@ type ServerHTTPStats struct {
 	CurrentS3Requests ServerHTTPAPIStats `json:"currentS3Requests"`
 	TotalS3Requests   ServerHTTPAPIStats `json:"totalS3Requests"`
 	TotalS3Errors     ServerHTTPAPIStats `json:"totalS3Errors"`
+	TotalS3Canceled   ServerHTTPAPIStats `json:"totalS3Canceled"`
 }
 
 // ServerInfoData holds storage, connections and other

cmd/http-stats.go

@@ -17,6 +17,7 @@
 package cmd
 
 import (
+	"context"
 	"net/http"
 	"strings"
 	"sync"
@@ -141,6 +142,7 @@ type HTTPStats struct {
 	currentS3Requests HTTPAPIStats
 	totalS3Requests   HTTPAPIStats
 	totalS3Errors     HTTPAPIStats
+	totalS3Canceled   HTTPAPIStats
 }
 
 func (st *HTTPStats) addRequestsInQueue(i int32) {
@@ -160,6 +162,9 @@ func (st *HTTPStats) toServerHTTPStats() ServerHTTPStats {
 	serverStats.TotalS3Errors = ServerHTTPAPIStats{
 		APIStats: st.totalS3Errors.Load(),
 	}
+	serverStats.TotalS3Canceled = ServerHTTPAPIStats{
+		APIStats: st.totalS3Canceled.Load(),
+	}
 	return serverStats
 }
 
@@ -175,6 +180,13 @@ func (st *HTTPStats) updateStats(api string, r *http.Request, w *logger.Response
 		if !successReq && w.StatusCode != 0 {
 			st.totalS3Errors.Inc(api)
 		}
+		select {
+		case <-r.Context().Done():
+			if err := r.Context().Err(); err == context.Canceled {
+				st.totalS3Canceled.Inc(api)
+			}
+		default:
+		}
 	}
 
 	// Increment the prometheus http request response histogram with appropriate label

cmd/logger/audit.go

@@ -49,7 +49,7 @@ type ResponseWriter struct {
 }
 
 // NewResponseWriter - returns a wrapped response writer to trap
-// http status codes for auditiing purposes.
+// http status codes for auditing purposes.
 func NewResponseWriter(w http.ResponseWriter) *ResponseWriter {
 	return &ResponseWriter{
 		ResponseWriter: w,

cmd/metrics-v2.go

@@ -74,6 +74,7 @@ type MetricName string
 const (
 	total         MetricName = "total"
 	errorsTotal   MetricName = "error_total"
+	canceledTotal MetricName = "canceled_total"
 	healTotal     MetricName = "heal_total"
 	hitsTotal     MetricName = "hits_total"
 	inflightTotal MetricName = "inflight_total"
@@ -495,6 +496,15 @@ func getS3RequestsErrorsMD() MetricDescription {
 		Type:      counterMetric,
 	}
 }
+func getS3RequestsCanceledMD() MetricDescription {
+	return MetricDescription{
+		Namespace: s3MetricNamespace,
+		Subsystem: requestsSubsystem,
+		Name:      canceledTotal,
+		Help:      "Total number S3 requests that were canceled from the client while processing",
+		Type:      counterMetric,
+	}
+}
 func getCacheHitsTotalMD() MetricDescription {
 	return MetricDescription{
 		Namespace: minioNamespace,
@@ -576,6 +586,7 @@ func getHealObjectsHealTotalMD() MetricDescription {
 		Type:      gaugeMetric,
 	}
 }
+
 func getHealObjectsFailTotalMD() MetricDescription {
 	return MetricDescription{
 		Namespace: healMetricNamespace,
@@ -1077,6 +1088,13 @@ func getHTTPMetrics() MetricsGroup {
 					VariableLabels: map[string]string{"api": api},
 				})
 			}
+			for api, value := range httpStats.TotalS3Canceled.APIStats {
+				metrics = append(metrics, Metric{
+					Description:    getS3RequestsCanceledMD(),
+					Value:          float64(value),
+					VariableLabels: map[string]string{"api": api},
+				})
+			}
 			return
 		},
 	}

cmd/metrics.go

@@ -372,6 +372,18 @@ func httpMetricsPrometheus(ch chan<- prometheus.Metric) {
 			api,
 		)
 	}
+
+	for api, value := range httpStats.TotalS3Canceled.APIStats {
+		ch <- prometheus.MustNewConstMetric(
+			prometheus.NewDesc(
+				prometheus.BuildFQName(s3Namespace, "canceled", "total"),
+				"Total number of client canceled s3 request in current MinIO server instance",
+				[]string{"api"}, nil),
+			prometheus.CounterValue,
+			float64(value),
+			api,
+		)
+	}
 }
 
 // collects network metrics for MinIO server in Prometheus specific format