We are using a SpringBoot service that uses SseEmitter to implement Server Sent Events back to the client.

From the standpoint of observability, I am wondering if there are any metrics that are specific to SSE I should be aware of. This would be in addition to the standard HTTP metrics around status_code or latency, for example.

I am new to this, and uncertain of what types of things can occur in a production environment. Some examples of things I was considering:

• the number of open connections
• an error occurs sending an event to the client for some reason
• a connection is closed
• a connection is opened

A look at Spring documentation and searching on the web has not yielded anything fruitful.