How to generate custom INFO metrics with recording rules?
The only workaround for this we've found is to use absent and non_exist together so it creates a custom INFO metric.
e.g. recording rule named "networks_id" defined as:
absent(non_exist{network_id="1",network_name="Ethereum"})
will create series
networks_id{{network_id="1", network_name="Ethereum Mainnet"}
where "non_exists" is just a string for metric name we don't have scraped...
Is there a more common way to accomplish this with prometheus recording rules?
I believe your approach is the most common one for creating vectors with arbitrary labels.
One alternative way might be using label_replace to add label you want:
label_replace(vector(1), "label", "label_value", "", "")
This is particularly useful when you want add label to something already present. But for completely artificial vectors approach with absent is usually preferred, due to it's conciseness (with label_replace, you'd need one call of function for each new label).