How to design a proactive monitoring system?

This is a vague question on design. I have microservice which performs order management. The service orchestrates every order from Placed to Delivered. A lot of things happening in between. Let say …

How to monitor incoming and outgoing network bytes from express & socket.io servers

I have an express server which also contains socket.io on it. I want to know how many bytes going outside and coming inside on each clients’ requests including HTTP and Socket (WSS). I’m looking for a …