allow passing a string to the ready configuration block in prometheus exporter

[matthewdarwin]

We have different "firehose block versions" of an app running at the same time. I would be great if the ready status in the prometheus exporter could say which version was running.

Eg

# HELP ready readiness of an app. 1 if ready, 0 otherwise
# TYPE ready gauge
ready{app="firehose", block-version="v3"} 0

Where this might be configured as common-reporting-block-version: v3.

This is just for reporting, firehose doesn't do anything with it otherwise.

This was originally streamingfast/firehose-ethereum#68

[maoueh]

Would you be fine with common-metrics-tags (not quite sure of the best name) so that you could provide a few user chosen tags so we could do --common-metrics-tags="block-version=v3,datacenter=d1".

What do you think?

[matthewdarwin]

Sure.