thingsboard遥测数据确认机制

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我是靠谱客的博主高挑乌冬面，最近开发中收集的这篇文章主要介绍thingsboard遥测数据确认机制，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

为了确保遥测数据被thingsboard接收到，在设备以及thingsboard之间传递时序数据是有确认机制的，具体在transport-mqtt模块中，如下所示：

下面看下MqttTransportHandler类相关部分代码

    private void processPublish(ChannelHandlerContext ctx, MqttPublishMessage mqttMsg) {
        if (!checkConnected(ctx, mqttMsg)) {
            return;
        }
        String topicName = mqttMsg.variableHeader().topicName();
        int msgId = mqttMsg.variableHeader().packetId();
        log.trace("[{}][{}] Processing publish msg [{}][{}]!", sessionId, deviceSessionCtx.getDeviceId(), topicName, msgId);

        if (topicName.startsWith(MqttTopics.BASE_GATEWAY_API_TOPIC)) {
            if (gatewaySessionHandler != null) {
                // 通过网关上传数据
                handleGatewayPublishMsg(topicName, msgId, mqttMsg);
                transportService.reportActivity(sessionInfo);
            }
        } else {
            // 通过设备上传数据
            processDevicePublish(ctx, mqttMsg, topicName, msgId);
        }
    }

下面看下processDevicePublish相关部分，从下面的代码可以看到端倪：将遥测数据发送队列后会执行getPubAckCallback进行数据ack操作

private void processDevicePublish(ChannelHandlerContext ctx, MqttPublishMessage mqttMsg, String topicName, int msgId) {
        try {
              // 发送遥测数据
            if (topicName.equals(MqttTopics.DEVICE_TELEMETRY_TOPIC)) {
                TransportProtos.PostTelemetryMsg postTelemetryMsg = adaptor.convertToPostTelemetry(deviceSessionCtx, mqttMsg);
                // getPubAckCallback是成功回调
                transportService.process(sessionInfo, postTelemetryMsg, getPubAckCallback(ctx, msgId, postTelemetryMsg));
            }

    private <T> TransportServiceCallback<Void> getPubAckCallback(final ChannelHandlerContext ctx, final int msgId, final T msg) {
        return new TransportServiceCallback<Void>() {
            @Override
            public void onSuccess(Void dummy) {
                log.trace("[{}] Published msg: {}", sessionId, msg);
                if (msgId > 0) {
                    // 发送回执
                    ctx.writeAndFlush(createMqttPubAckMsg(msgId));
                }
            }

            @Override
            public void onError(Throwable e) {
                log.trace("[{}] Failed to publish msg: {}", sessionId, msg, e);
                processDisconnect(ctx);
            }
        };
    }