After you use the sample code to connect a device to IoT Platform over Message Queuing Telemetry Transport (MQTT), you can view logs on the device.
Prerequisites
For more information, see Example.
Device logs
You can view the running result on the device.
Device connection logs
The following log data indicates that the device is connected to IoT Platform.
[1583135792.733][LK-0313] MQTT user calls aiot_mqtt_connect api, connect [1583135792.733][LK-0317] LightSwitch&a18wP****** [1583135792.733][LK-0318] 3FC4A3DED5AC5F31C4969CBB1868758B17FAB2E5070FC51C9880910472****** [1583135792.733][LK-0319] a18wP******.LightSwitch|timestamp=2524608000000,_ss=1,_v=sdk-c-4.0.0,securemode=2,signmethod=hmacsha256,ext=1,| establish mbedtls connection with server(host='a18wP******.iot-as-mqtt.cn-shanghai.aliyuncs.com', port=[443]) success to establish mbedtls connection, fd = 6(cost 44763 bytes in total, max used 47675 bytes) [1583135792.888][LK-0313] MQTT connect success in 147 ms AIOT_MQTTEVT_CONNECTTopic subscription logs
If you want to send a broadcast message to all devices under a product, the devices must subscribe to the broadcast topic, such as
/broadcast/a18wP******/test. After subscription, the following log data is generated:[1624933980.266][LK-0309] sub: /broadcast/a18wP******/test suback, res: -0x0000, packet id: 1, max qos: 1Logs about message broadcasting
Send a broadcast message to a specified topic
You can call the PubBroadcast operation of IoT Platform to send a broadcast message to a specified topic. The following log data indicates that the
helloworldmessage is sent to the/broadcast/a18wP******/testtopic:[1624934078.899][LK-0309] pub: /broadcast/a18wP******/test [LK-030A] < 68 65 6C 6C 6F 77 6F 72 6C 64 | helloworld pub, qos: 0, topic: /broadcast/a18wP******/test pub, payload: helloworldSend a broadcast message to all online devices
You can also call the PubBroadcast operation of IoT Platform to send a broadcast message such as
helloworldto all online devices under a specified product. In this example, the following log data is generated.Log data:
[1624934109.099][LK-0309] pub: /sys/a18wP******/LightSwitch/broadcast/request/1409701944049****** [LK-030A] < 68 65 6C 6C 6F 77 6F 72 6C 64 | helloworld pub, qos: 1, topic: /sys/a18wP******/LightSwitch/broadcast/request/1409701944049****** pub, payload: helloworldLog description:
/sys/a18wP******/LightSwitch/broadcast/request/1409701944049******indicates the topic to which the broadcast message is sent.1409701944049******indicates the message ID. For more information, see Broadcast messages.
IoT Platform logs
You can log on to the IoT Platform console . In the left-side navigation pane, choose . Select a product to view the communication logs of the device.
What to do next
For more information about error messages in logs, see Common error codes