Is OpenTelemetry intended for event-based metrics export?

[BlueskyFR]

By default, the only implementation of the abstract class MetricReaderAbstract is PeriodicExportingMetricReader, meaning that metrics are exported every X seconds.

I am retrieving metrics from somwhere at a non-fixed interval. It is around every 5 minutes but it sometimes takes less, sometimes more so I want to call the "push" event myself every time, to only push when my data is updated (all at once).

Seems to me that a different class would be required for that (like EventBasedExportingMetricReader).

My use case seems pretty simple so I was wondering if maybe I just got it wrong?

A way would certainly be to set PeriodicExportingMetricReader to 999999 seconds and force_push I guess? But it's a bit ugly

[pichlermarc]

Hi @BlueskyFR - from my knowledge of the OpenTelemetry Specification I'd say that this use-case is not supported. We'd actually need a OpenTelemetry SDK Specification amendment that triggers an event of sorts, so that a metric reader could listen to whenever a metric was written. At this point it may be easier to use the logs API with a SimpleLogRecordProcessor and then you count the logs at some intermediate component (like https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/connector/countconnector/README.md)

[BlueskyFR]

Mmh yeah but I really need to export metrics actually.
Why is there such a difference between the JS SDK and the Go Collector?

[pichlermarc]

Mmh yeah but I really need to export metrics actually.

I understand - however, here we only implement the OpenTelemetry Specification, and the Specification does not support such a concept, hence we also do not. I would assume the OpenTelemetry Go SDK does also not support such a use-case due to the same reason.

What I linked here is a seperate component from the OpenTelemetry Go SDK: the OpenTelemetry Collector. The collector is deployed outside of your app and can used to process data to support a wide variety of use-cases. Converting logs data via a connector would be one of the ways I can see to accomplish what you're trying to do.