Adding functionality to the attributes processor to dynamically update attribute values

[stainlessfawn]

I have a requirement where a set of attributes need to be applied to all metrics that leave a machine. There is an otel collector running on the machine, and it seems like this would be the ideal place to add these attributes to every metric.

The only gotcha here is these attributes could dynamically change as the source of truth is not the config.yml used by the collector. There exists a JSON file that contains common information already used by other processes. It seems like a natural fit to leverage this file to retrieve the attributes.

Requirements

• Reads attributes from a JSON file and attaches it to all metrics
• When the JSON file is changed, the attributes applied to the metrics are updated in near real time

At a high level, this seems to fit in with the attributes processor, but it could also be implemented as a separate processor specifically for reading JSON file (I've prototyped this approach and a basic implementation does work).

Has there been any thought around this scenario in the past? If not, do you think it would fit in with the attributes processor or a new one?