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Log 文件 ​

MQTT服务器端的日志文件无论对MQTT服务器端的开发人员，还是对MQTT客户端的开发人员都是很重要的。

  • Log 可以帮助MQTT服务器端开研发工程师快速定位bug位置
  • Log 可以帮助利用MQTT物联网开发人员快速定位问题
  • Log 是协助物联网开发人员调试程序的利器

鉴于Log的重要性，FreeMQTT精心设计所输出的Log内容和格式，尽量让研发人员易读易懂。 FreeMQTT不会输出与MQTT无关的内部软件信息，也不会出现杂乱无章的垃圾信息。

Log 样例 ​

log
[I 240921 08:43:30 waiter:182] TCP connecting from ('127.0.0.1', 57153)
[I 240921 08:43:30 authplugin:22] AppID: h2agent@mqtt
[I 240921 08:43:30 waiter:256] new session, app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:265] R CONNECT clean_start(1) keep_alive_interval(10) level(5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:318] S CONNACK app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 session:171] S PUBLISH t:$SYS/ONLINE (d0 q1 r0 m1 v5) app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:43:30 waiter:448] R PUBACK (m1 v5) app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:43:30 waiter:505] R SUBSCRIBE (m36831 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:522]   item-01: tf:ben/# qos:1 option:0x11 valid:True
[I 240921 08:43:30 waiter:494] S SUBACK (m36831 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:341] R PUBLISH t:ben/3/3 (d0 q1 r0 m36832 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:414] S PUBACK (m36832 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 session:171] S PUBLISH t:ben/3/3 (d0 q1 r0 m1 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:448] R PUBACK (m1 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:48:14 session:147] S PUBLISH $SYS/METRICS (d0 q0 r0 m0 v5) app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:48:44 waiter:635] TIMEOUT app/cid:h2agent@mqtt/mqttx_0471e865 ip:('127.0.0.1', 57133)
[E 240921 08:48:44 waiter:198] remote: ('127.0.0.1', 57133) be closed
[I 240921 08:48:46 waiter:593] Will Message topic: will/test qos: 1 app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:49:00 waiter:635] TIMEOUT app/cid:h2agent@mqtt/mqttx_12677d28 ip:('127.0.0.1', 57153)
[E 240921 08:49:00 waiter:198] remote: ('127.0.0.1', 57153) be closed
[I 240921 08:49:02 waiter:593] Will Message topic: will/test qos: 1 app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:49:06 waiter:647] Session expired app/cid:h2agent@mqtt/mqttx_0471e865

Log详解 ​

log
[I 240921 08:43:34 waiter:341] R PUBLISH t:ben/3/3 (d0 q1 r0 m36832 v5) app/cid:h2agent@mqtt/mqttx_12677d28

如上面的log条目所表明的信息依次是：

  • 方括号里第一个字符代表Log级别: I-Info, D-debug, E-error, W-warning, C-critical
  • 年月日时间 240921 08:43:34
  • 模块名称和行号 waiter:341
  • R PUBLISH 表示服务器收到PUBLISH包, 如果S PUBLISH则表示发送消息
  • t:ben/3/3 表示 Topic 是 ben/3/3
  • (d0 q1 r0 m36832 v5) 含义：
    • d0：非重发消息
    • q1: QoS 为 1
    • r0: 非保留消息
    • m36832: 消息包的ID为36832
    • v5: 客户端的MQTT协议为 MQTT5.0, 如果是 v4 则为MQTT3.1.1
  • app/cid:app/cid:h2agent@mqtt/mqttx_12677d28
    • Application Id 为 h2agent@mqtt
    • MQTT ClientId 为 mqttx_12677d28

实时查看 ​

以Linux平台为例（Windows平台，需要借助 git bash, 否则没有 tail 命令）

  1. 进入FreeMQTT安装的路径：cd ./freemqttd
  2. 进入log路径： cd ./log
  3. 查看实时log: tail -f ./freemqtt.log

实际操作如下所示

bash
DELL@BEN-DELL-15R5537 MINGW64 /e/temp
$ cd ./freemqttd

DELL@BEN-DELL-15R5537 MINGW64 /e/temp/freemqttd
$ cd log

DELL@BEN-DELL-15R5537 MINGW64 /e/temp/freemqttd/log
$ tail -f ./freemqtt.log
[I 240921 08:43:30 waiter:182] TCP connecting from ('127.0.0.1', 57153)
[I 240921 08:43:30 authplugin:22] AppID: h2agent@mqtt
[I 240921 08:43:30 waiter:256] new session, app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:265] R CONNECT clean_start(1) keep_alive_interval(10) level(5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:318] S CONNACK app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 session:171] S PUBLISH t:$SYS/ONLINE (d0 q1 r0 m1 v5) app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:43:30 waiter:448] R PUBACK (m1 v5) app/cid:h2agent@mqtt/mqttx_0471e865
[I 240921 08:43:30 waiter:505] R SUBSCRIBE (m36831 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:30 waiter:522]   item-01: tf:ben/# qos:1 option:0x11 valid:True
[I 240921 08:43:30 waiter:494] S SUBACK (m36831 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:341] R PUBLISH t:ben/3/3 (d0 q1 r0 m36832 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:414] S PUBACK (m36832 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 session:171] S PUBLISH t:ben/3/3 (d0 q1 r0 m1 v5) app/cid:h2agent@mqtt/mqttx_12677d28
[I 240921 08:43:34 waiter:448] R PUBACK (m1 v5) app/cid:h2agent@mqtt/mqttx_12677d28