Reconnecting smoothly

https://github.com/aws/aws-iot-device-sdk-python/blob/47363e9b9bc0a4ecd5896d0f90cc685498e9b3ea/AWSIoTPythonSDK/core/protocol/mqtt_core.py#L248

Hello,

First thanks for creating/maintaining this sdk. From the documentation, it states that you provide:

It provides basic synchronous MQTT operations in the classic MQTT publish-subscribe model, along with configurations of on-top features: - Auto reconnect/resubscribe - Progressive reconnect backoff - Offline publish requests queueing with draining

However, I’m not experiencing these features. I expect when I call awsMQTTClient.publish(topic, message, qos) I expect not to ever get a publishTimeoutException(), except maybe when the maxReconnectQuietTimeSecond in configureAutoReconnectBackoffTime (docs) is exceeded. However, I get publishTimeoutException() quite often.

Do I have to do something like this now everytime I publish?

        try:
            myMQTTClient.publish("testing/IoT", message, 1)
        except:
            print(err)
            myMQTTClient.connect()
            myMQTTClient.publish("testing/IoT", message, 1)

What’s the proper way of recovering from this type of timeout?

[graebm]

Publishes do not affect the client’s attempts to reconnect. Reconnects occur when the underlying socket reports that the connection is lost, or when the MQTT Client doesn’t get a response to the PING packets it is sending to the server at regular intervals (“keep alive” values affect the rate that these PING packets are sent)

[GlennS]

Just noting that I had a similar issue when running inside uwsgi (using Flask), in case anyone else comes across this and needs help.

I fixed it by making sure to construct and connect my AWSIoTMQTTClient instance in the same context (probably a thread?) that requests run in. I still reuse the instance between different requests though, because calling connect() on the client takes some time.