Starlark Processor: Return multiple metrics from plugin

[sjwang90]

Feature Request

Opening a feature request kicks off a discussion.

Proposal:

Return multiple metrics from Starlark processor plugin

Current behavior:

Currently can only return (create) one metric from the Starlark

Desired behavior:

• Return multiple metrics.
• Approaches:
  1. Add a new function add() to add new metrics in the starlark processor. Use case: parse an array of json items and add one metric per item in the array
  2. Return an array or a tuple in the apply function. Currently we return the metric if we want to keep it. If we want to make multiple metrics from one, more natural to return multiple metrics rather than call an add() function

Use case:

• Parse an array of json items and add one metric per item in the array

[srebhan]

Hey @sjwang90, back when I discussed the starlark processor, @danielnelson was against handling multiple metrics as once (basically enabling aggregation etc.). I don't remember the reasoning.
Do you want multiple in, multiple out or single in multiple out?

[ssoroka]

always single in, 0 or more out.

[essobedo]

The corresponding PR #8423 that shows how to do it

[ssoroka]

fixed in #8423