Add metrics transform processor

[alelevinas]

https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/metricstransformprocessor

[alelevinas]

@andreasgerstmayr do you think we can include this component in the next release?

[andreasgerstmayr]

@alelevinas we currently include the transform processor (https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/transformprocessor)

Do you have a specific use case in mind which the transform processor does not support?

[alelevinas]

@alelevinas we currently include the transform processor (https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/transformprocessor)

Do you have a specific use case in mind which the transform processor does not support?

Basically to add labels to metrics which the transform-processor doesn't support. Let me know what you think!

[andreasgerstmayr]

@alelevinas we currently include the transform processor (https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/transformprocessor)
Do you have a specific use case in mind which the transform processor does not support?

Basically to add labels to metrics which the transform-processor doesn't support. Let me know what you think!

Can you try

metric_statements:
  - set(resource.attributes["test"], "passed")

(from https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/2b306ce0c92e06e69e0e129e2f1739021f21ffea/processor/transformprocessor#context-inference)

I didn't test it yet, but it should set the resource attribute (i.e. the label) test to passed.