Question

Can we count AWS IoT successful connection number and message number and through a threshold notification

Answer 1

Yes it is possible. You may take following approaches:

One: Create a topic rule that listens to lifecycle topics. The rule could push a custom metric into AWS Cloudwatch or may even invoke a lambda that has more complex logic.

Two: Turn on the IOT logs, and setup a Lambda subscription to the IoT log group. The Lambda function could then push a custom metric into AWS CloudWatch.