如何在 fluentd 中为以下 nginx 访问日志格式编写正则表达式?
log_format main '$remote_addr - $remote_user [$time_local] $request '
'"$status" $body_bytes_sent "$http_referer" '
'"$http_HOST" $HOST '
'"$http_user_agent" "$http_x_forwarded_for" '
'upstream_response_time $upstream_response_time '
'upstream_addr $upstream_addr '
'msec $msec request_time $request_time';