Summary

Routine Change

• No functional changes; purely refactoring into controller -> service -> repository

• Added error scenarios for the Create Imms journey into the FHIR API exception decorator

• Moved the duplicate checking into the service layer.

• Simplified each layer, improved readability and return types.

• Additionally added some extra terraform constraints which I think will help with the fresh environment deployment flakiness

• FOR DISCUSSION: I have modified the code so that the service passes around the actual FHIR Immunization entity rather than dicts. Dicts are mutable and do not help to document the code. If we do not want to do this, I can remove the commit (number 4 I think). One other thing to consider is that it will change the ordering of the JSON that is dumped to the DB. E.g. previously "id" would be the last key as it was added last, but now it will be at the top, just after resource, because we are using the .json method of the FHIR entity. Hopefully that is okay - as the Get endpoint also uses the FHIR resource to dump so it will not affect anything the client sees when retrieving. As long as we don't care about the particular ordering of what is actually stored to Dynamo then should be fine.

Reviews Required

• Dev

Review Checklist

ℹ️ This section is to be filled in by the reviewer.

• I have reviewed the changes in this PR and they fill all or part of the acceptance criteria of the ticket, and the code is in a mergeable state.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• I have ensured the changelog has been updated by the submitter, if necessary.