Design plan:

1. Provide HTTP/Websocket services, and use whether the Websocket is connected as the basis for judging whether it is online.
2. Use MongoDB database to store the indicator data pushed by the client and support horizontally scalable cluster services.
3. Provide some interfaces to provide data for Prometheus.
4. Provide some management interfaces or functions, such as data cleaning, persistence, etc.

Note: MongoDB 5.0 version is too low, the time series function is incomplete, and there are bugs. You need to use the latest version 7.0 or above.