We are developing a custom mapper plugin that transforms data to the Fivetran format. It appears we have to define at least a single

mapping

in the

meltano.yml

for it to work with

meltano run

mappers:
  - name: mapper-fivetran
    namespace: mapper_fivetran
    variant: matatika
    pip_url: -e /home/reuben/Documents/mappers/mapper-fivetran
    mappings:
    - name: fivetran

otherwise we get the error message

block violates set requirements: Expected unique mappings name not the mapper plugin name: mapper-fivetran

. Would it be possible/does it makes sense to reference a mapper plugin with predefined behaviours directly like this?

I think we had a GitHub issue for that, but I can't find it. It'd require some refactoring, but I can imagine we could inject the mapper itself as the first and always available mapping. Wdyt?

Yeah, I did have a look myself but couldn't find anything. Your proposal sounds good, but is there a reason that wasn't the case initially?

The details are fuzzy, and the context is probably spread in a few GitLab issues and MRs 😕 • https://gitlab.com/meltano/meltano/-/merge_requests/2481 • https://gitlab.com/meltano/meltano/-/issues/2299 • https://gitlab.com/meltano/meltano/-/issues/3273

I think we had a GitHub issue for that,

Might be this one? https://github.com/meltano/meltano/issues/3233 or at least part of it.

Ah I didn't realize

meltano invoke <mapper>

actually worked! It doesn't seem to difficult then to do the same for mappers.