VED-917: Further Refactoring

[JamesW1-NHS]

Summary

• Routine Change

To refactor elements of lambdas into shared/ which we didn't do in VED-807.

Refactor ack file handling from filenameprocessor/recordprocessor (make_and_upload_ack_file)
Make singleton from sqs_client
Make singleton from all other clients (dynamodb, firehose, etc.)

Notes:

• We won't refactor the local functions from fhir_repository/fhir_batch_repository. These contain PK values and should remain in the API and batch projects.
• I have removed the tests from test_clients.py which check that a global client variable is None at import time. Reason: such a variable could be set in preceding tests. The remaining tests suffice to test that a global client variable is never created more than once. The alternative would have been to reintroduce importlib.reload(), which would create side-effects in other test modules.

Reviews Required

• Dev
• Test
• Tech Author
• Product Owner

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 of the acceptance criteria of the ticket.
• If there were infrastructure, operational, or build changes, I have made sure there is sufficient evidence that the changes will work.
• If there were changes that are outside of the regular release processes e.g. account infrastructure to setup, manual setup for external API integrations, secrets to set, then I have checked that the developer has flagged this to the Tech Lead as release steps.
• I have checked that no Personal Identifiable Data (PID) is logged as part of the changes.

[github-actions]

This branch is working on a ticket in the NHS England VED JIRA Project. Here's a handy link to the ticket:

VED-917

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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