Add the duration and start time to logged completed requests. (#13682)

Author: ncabatoff

changelog/13682.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+core: Add duration and start_time to completed requests log entries
+```

vault/core.go

@@ -3044,7 +3044,12 @@ func (c *Core) LogCompletedRequests(reqID string, statusCode int) {
 
 	// there is only one writer to this map, so skip checking for errors
 	reqData := v.(InFlightReqData)
-	c.logger.Log(logLevel, "completed_request", "client_id", reqData.ClientID, "client_address", reqData.ClientRemoteAddr, "status_code", statusCode, "request_path", reqData.ReqPath, "request_method", reqData.Method)
+	c.logger.Log(logLevel, "completed_request",
+		"start_time", reqData.StartTime.Format(time.RFC3339),
+		"duration", fmt.Sprintf("%dms", time.Now().Sub(reqData.StartTime).Milliseconds()),
+		"client_id", reqData.ClientID,
+		"client_address", reqData.ClientRemoteAddr, "status_code", statusCode, "request_path", reqData.ReqPath,
+		"request_method", reqData.Method)
 }
 
 func (c *Core) ReloadLogRequestsLevel() {