We had a similar request to create a Podman runner [1]. Below are some comments that are probably relevant to this discussion:
We provide a framework that lets anyone in the community create a custom runner. There is no difference between an official runner and a community runner other than stewardship. The starter project and framework for creating a customer runner:
GitHub - drone/boilr-runner: boilr template for creating custom pipeline runners
The tooling to create a custom runner is new and has not been formally announced or documented yet, however, a few community members were able to use the starter project and research existing runners to figure it out. I am happy to answer any questions.
Note that a podman runner would need to be its own separate runner, similar to how the kubernetes runner is its own separate runner. We would not combine the docker runner and podman runner into a single codebase.
Similar to our suggestion above, you would need to create a separate Fargate runner. We would not combine a Fargate runner and a docker runner in the same codebase. Instead we would try to create something Fargate-specific, using Fargate-specific configuration options where needed, without having to worry about full syntax compatibility with Docker or Kubernetes pipelines. The starter project should simplify development and will handle most of the boilerplate code, leaving TODO placeholders for you to write code that is specific to Fargate and AWS.