Keep every shadowed setting while choosing the last declared value.
Type: Build Languages: Go Stage: 2 of 4 Prerequisites: Basic functions, collections, JSON and the previous stages when applicable. Time: ~2 hours
What you build
Implement Resolve over validated layers. A later layer overrides an earlier one. Preserve all source names and values in order for each key. Resolution is an internal operation and can contain secrets; only the report is safe to export.
Worked example
timeout has history [(defaults.json,30),(env:TIMEOUT,5)] and effective value 5. An unrelated region value remains local. Explicit null replaces an earlier value instead of deleting the key.
pj configuration drift explainer 2
Implement the contract
Resolve(layers []Layer) map[string]Effective, where Effective{Value any, History []Source} and Source{Layer string, Value any}. Empty layers produce an empty map.
Reject malformed input before producing a partial artifact. The tests include held-out records separate from the demonstration fixture.
Run your work
python3 scripts/project_test.py configuration-drift-explainer --init /tmp/configuration-drift-explainer-work
python3 scripts/project_test.py configuration-drift-explainer --stage 2 --path /tmp/configuration-drift-explainer-work --strictInitialization copies cumulative scaffolding without replacing your work. Implement the TODO functions in the first-stage starter; later-stage starter notes describe the new behavior. Tests import the learner workspace. Run the command in the README against your own input after passing the stage.
Inspect and extend
Compare explicit null, missing key and an empty string. They represent three different effective configurations.
Go standard library and Node standard library. All fixtures and implementations are original.