Metric for response body size

[syd20]

I did't find anything in the document about a metric for response size? Can we have a metric for emitting the response body size? I have a use case where I would like to check the content length and configure alerting if it's below the threshold

[manugarg]

I think tracking individual use case like this is not going to work well. I'm trying to think of some generic approach to validators.

[syd20]

Here I would not require a validator but just the response body size to be sent as a metric similar to those for latency and status codes. I do agree we would need some generic long term approach for validator especially where we need some dynamic comparison

[manugarg]

Adding a new metric is expensive in the sense that it affects everyone automatically, so we don't do that unless it's something that applies to a lot of use cases, and there is a significant demand for it.

Validators are less invasive as you have to explicitly enable them. One thing we can add to validators is an option to mark probe as success even if that validator fails -- this will allow users to generate/use validator metrics without failing the probe.

Another option we've been thinking of for a while is to generate metrics from HTTP responses: #356
We can possibly utilize that option to generate metrics from headers as well.