humanize `timeToFirstByte` and `timeToResponse` upto nanoseconds (#9641)

cmd/logger/audit.go

@@ -22,6 +22,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"strconv"
 	"time"
 
 	"github.com/gorilla/mux"
@@ -166,8 +167,11 @@ func AuditLog(w http.ResponseWriter, r *http.Request, api string, reqClaims map[
 	entry.API.Object = object
 	entry.API.Status = http.StatusText(statusCode)
 	entry.API.StatusCode = statusCode
-	entry.API.TimeToFirstByte = timeToFirstByte.String()
+	entry.API.TimeToResponse = strconv.FormatInt(timeToResponse.Nanoseconds(), 10) + "ns"
-	entry.API.TimeToResponse = timeToResponse.String()
+	// ttfb will be recorded only for GET requests, Ignore such cases where ttfb will be empty.
+	if timeToFirstByte != 0 {
+		entry.API.TimeToFirstByte = strconv.FormatInt(timeToFirstByte.Nanoseconds(), 10) + "ns"
+	}
 
 	// Send audit logs only to http targets.
 	for _, t := range AuditTargets {

docs/logging/README.md

@@ -57,6 +57,9 @@ minio server /mnt/data
 ```
 
 Setting this environment variable automatically enables audit logging to the HTTP target. The audit logging is in JSON format as described below.
+
+NOTE: `timeToFirstByte` and `timeToResponse` will be expressed in Nanoseconds.
+
 ```json
 {
   "version": "1",
@@ -68,8 +71,8 @@ Setting this environment variable automatically enables audit logging to the HTT
     "object": "hosts",
     "status": "OK",
     "statusCode": 200,
-    "timeToFirstByte": "0s",
+    "timeToFirstByte": "366333ns",
-    "timeToResponse": "2.143308ms"
+    "timeToResponse": "16438202ns"
   },
   "remotehost": "127.0.0.1",
   "requestID": "15BA4A72C0C70AFC",