Implement an 'InterpolateString' function in the OTTL parser.

[michaelsafyan]

Description

Provide an InterpolateString function in the OTTL parser library. This will enable OTTL expressions to be used to construct URIs from patterns that contain OTTL sub-expressions to substitute, allowing pieces of the input signal to be used to be used to derive the URI. This will be helpful for configuring a mechanism to write-aside pieces of a signal.

Links to related issues

• Implements:
  • Please make it easy to do simple string interpolation using the OTTL library to facilitate developing other components #34700
• Unblocks:
  • New component: Blob Upload Processor #33737

Testing

This adds integration tests to e2e_test.go that verify that this interpolation works. The tests verify that:

• This works with more than one type of OTTL signal / "TransformContext" type
• This handles reference both to present and absent values in the signal
• This handles the use of a ":default" suffix to fallback where a property or attribute is missing

In addition, this implementation is identical to that being used in the prototype in blobattributeuploadconnector, and the end-to-end tests for the connector that makes use of this function additionally verifies correct behavior.

Documentation

The function, itself, has comments documenting this function. However, we have not added more documentation beyond that. I think it would be ideal to get this in as-is at this stage and to defer any additional documentation to later, especially given that this library function is not directly invocable by users, and there is not yet evidence that other component authors have any confusion regarding how to use this function (and thus it is not clear what additional docs are needed).

[michaelsafyan]

@songy23 hope you're doing well! I'm new to contributing to this repo, so pardon if I'm missing some of the process ... roughly what timetable can I expect a review? Is there a possibility of this getting reviewed some time soon?

This is blocking me from upstreaming other parts of #33737 . Thanks!

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This PR was marked stale due to lack of activity. It will be closed in 14 days.

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Closed as inactive. Feel free to reopen if this PR is still being worked on.