Plugin Model

Each AWS service is analyzed by an independent scanner. Scanners implement the WasteScannerPort interface defined in the domain layer. The coordinator (AnalyzeCloudWasteUseCase) is generic over registered scanners — it knows nothing about specific services.

WasteScannerPort interface

Every scanner implements this port:

interface WasteScannerPort {
  readonly resourceKind: ResourceKind;
  scan(params: ScanParams): Promise<WastedResource[]>;
}

Existing scanners

Adding a new scanner

Step-by-step guide (from the README):

1. Add the new kind to the ResourceKind union type in wasted-resource.ts — the compiler then points to every spot that needs updating
2. Create the entity in libs/cloud-cost/domain/src/entities/ implementing WastedResource
3. Create the waste policy in libs/cloud-cost/domain/src/policies/ (grace period and ignore tag come free from the base class)
4. Add the price key to prices.json — PricingPort is a generic getPrice(region, key), no interface changes needed
5. Implement the scanner in libs/cloud-cost/infrastructure/aws-adapter/src/scanners/ (implements WasteScannerPort)
6. Register the presenter in apps/cli/src/formatters/resource-presenters.ts and the scanner in analyze-waste.composition.ts

No changes needed to AnalyzeCloudWasteUseCase, WastedResourcesSummary, WasteReportDto, or the formatters.

The TypeScript compiler guides the entire process: after adding the kind to the ResourceKind union, pnpm nx run-many -t typecheck shows exactly what needs to be completed.