We're using git and eb to deploy our elastic beanstalk application on aws, but have just added a worker layer. Given that so much of the code is common (models, etc etc), it seems sensible to have a single source base, but you can only have one eb config and the branch based deployment can only have one target.
An alternative is to have multiple source repositories with shared code.
Another is to have the eb config outside of the repo and have multiple instances of the repo.
Personally, I'd prefer one source base.
What is considered the best practice for git and multiple tier?