Dropping Exemplars Using Transform Processer

[shaiajneh]

Is it possible to drop exemplars from metrics using the transform processor and OTTL? I have a use case where I dont need exemplars coming from certain metrics and I want to drop it. I have tried using transform processor by using the following OTTL statement, but it did not have any effect. Context is set to data point.

set(datapoint.exemplars, [])

I have used Grafana Alloy to implement this, but it should use the upstream collector transform processor

otelcol.processor.transform "drop_exemplars" {
	metric_statements {
		context    = "datapoint"
		statements = [
			`set(datapoint.exemplars, [])`,
		]
	}

	output {
		metrics = [otelcol.processor.transform.attributes_processor.input]
	}
}

Is it even possible to mutate the exemplars field in datapoints?

[edmocosta]

Although OTTL exposes the datapoint.exemplars path, it's currently not possible to set it to empty or any other value using the OTTL syntax. The type this path exposes (pmetric.ExemplarSlice) isn't supported by the grammar, and the only possible operation with that path is copying it from another value of the same type.

[shaiajneh]

@edmocosta
Thanks for the answer.
Aside from using OTTL, do you know if there are any methods to drop exemplars?

[edmocosta]

Unfortunately I don't, I can't think about any existing collector processor that can do that. My suggestion is to ask it in the CNCF Slack channel (#otel-collector), maybe other folks have a solution for that :)