[processor/transform] Add ability to add element in array

[adelbot]

Component(s)

No response

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

I use an attributes that it is an array.
The collector receive this attributes and i must add a new element into.

The transform with "set" update this attributes.
The insert seem not exist

Describe the solution you'd like

Before

scope = ["aaa"]

transform/scope:
error_mode: ignore
trace_statements:
- context: resource
statements:
- insert(attributes["scope"], ["xxx"] )

After

scope = [ "aaa","xxx"]

Describe alternatives you've considered

No response

Additional context

No response

[github-actions]

Pinging code owners:

• processor/transform: @TylerHelmuth @kentquirk @bogdandrutu @evan-bradley @edmocosta

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[edmocosta]

Hi @adelbot! I think the append function would work for your use case:

trace_statements:
 - context: resource
   statements:
    - append(attributes["scope"], "xxx") # single value
    - append(attributes["scope"], values = ["aaaa", "bbb"]) # multiple values