add bucket level S3 received/sent bytes (#15084)

adds bucket level metrics for bytes received and sent bytes on all S3 API calls.

cmd/generic-handlers.go

@@ -271,6 +271,22 @@ func parseAmzDateHeader(req *http.Request) (time.Time, APIErrorCode) {
 	return time.Time{}, ErrMissingDateHeader
 }
 
+// splitStr splits a string into n parts, empty strings are added
+// if we are not able to reach n elements
+func splitStr(path, sep string, n int) []string {
+	splits := strings.SplitN(path, sep, n)
+	// Add empty strings if we found elements less than nr
+	for i := n - len(splits); i > 0; i-- {
+		splits = append(splits, "")
+	}
+	return splits
+}
+
+func url2Bucket(p string) (bucket string) {
+	tokens := splitStr(p, SlashSeparator, 3)
+	return tokens[1]
+}
+
 // setHttpStatsHandler sets a http Stats handler to gather HTTP statistics
 func setHTTPStatsHandler(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -287,9 +303,23 @@ func setHTTPStatsHandler(h http.Handler) http.Handler {
 			strings.HasPrefix(r.URL.Path, lockRESTPrefix) {
 			globalConnStats.incInputBytes(meteredRequest.BytesRead())
 			globalConnStats.incOutputBytes(meteredResponse.BytesWritten())
-		} else {
-			globalConnStats.incS3InputBytes(meteredRequest.BytesRead())
-			globalConnStats.incS3OutputBytes(meteredResponse.BytesWritten())
+			return
+		}
+		if strings.HasPrefix(r.URL.Path, minioReservedBucketPath) {
+			globalConnStats.incAdminInputBytes(meteredRequest.BytesRead())
+			globalConnStats.incAdminOutputBytes(meteredResponse.BytesWritten())
+			return
+		}
+
+		globalConnStats.incS3InputBytes(meteredRequest.BytesRead())
+		globalConnStats.incS3OutputBytes(meteredResponse.BytesWritten())
+
+		if r.URL != nil {
+			bucket := url2Bucket(r.URL.Path)
+			if bucket != "" && bucket != minioReservedBucket {
+				globalBucketConnStats.incS3InputBytes(bucket, meteredRequest.BytesRead())
+				globalBucketConnStats.incS3OutputBytes(bucket, meteredResponse.BytesWritten())
+			}
 		}
 	})
 }