[pkg/ottl] Add an ottl function that allows for the trimming of whitespaces or other specified symbols from an attribute

[robbavey]

Component(s)

pkg/ottl

Is your feature request related to a problem? Please describe.

I would like a simple way to trim whitespace from an attribute

Describe the solution you'd like

I would like to be able to trim data from an existing attribute

For example

A field test exists in an event, which contains the string " this is a test ".

I would like to be able to transform this using an ottl function trim, that I would define as trim(attribute["test"]), which would trim this down to "this is a test".

By default, this would use the unicode definition of whitespace, but we would also allow an alternative version trim(attribute, symbols)
I would also like to be able to set my own definition of whitespace, by providing a string containing the symbols I would like to trim.

Describe alternatives you've considered

A user could do this using the existing replace_all_patterns function, but this is a common enough function that it may warrant a standalone function. Additionally, we can be unambiguous that we replace the Unicode definition of whitespace by default.

Additional context

No response

[github-actions]

Pinging code owners:

• pkg/ottl: @TylerHelmuth @kentquirk @bogdandrutu @evan-bradley

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[evan-bradley]

@robbavey Thanks for the thorough proposal. Can you go into any detail about the situations you've seen where you've had to do trimming like this?

As for a trim function vs. using regular expressions, I think the following would cover this, and could be used as a template for custom prefix/suffix trimming: (^[\s\p{Zs}]+)|([\s\p{Zs}]+$). I'll admit that a function is more readable than a regular expression, but I want to make sure we think this will be used often enough to be worth having an additional function.

[robbavey]

@evan-bradley In general, I'm an advocate of simplicity for users, and removing places where they can accidentally craft an incorrect, or poorly performing regex (eg supplying an unanchored regex).

We see use of it a decent amount in Elasticsearch ingest pipelines used in Elastic integrations

[odubajDT]

Hi, is this ticket free for grab? Or it needs more discussion if it's worth implementing? I find it as a good idea

[TylerHelmuth]

I believe this function meets the criteria of https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/pkg/ottl/ottlfuncs/README.md#adding-new-editorsconverters and could be worked on. It should use strings.Trim.

[github-actions]

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[sjpalf]

I really dislike bots that close issues (especially after 60 days which isn't that long at all)