As tags aren't necessarily immutable, it's probably advisable to use the full hash in most situations anyway.
This is a useful trick in situations where the image changing under your feet isn't very important.
This is a useful trick in situations where the image changing under your feet isn't very important.
So the data element would lookup the tag, and the specific hash is used in the deployment. No funky replace triggers needed.
The point was more about using null_triggers (or `terraform_data` I see) and using the trigger replacement, with the docker resources as purely an illustration.