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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

Scanner Service Waste condition
EBS Volumes EC2/EBS Unattached (state: available)
EBS Volumes (idle) EC2/EBS Attached but zero I/O in 48h
EBS gp2→gp3 EC2/EBS gp2 volume upgradeable to gp3
Elastic IPs EC2 Not associated
EC2 Instances EC2 Stopped (attached EBS still billed)
EC2 (underutilized) EC2 Running, max CPU ≤ 5% in 14 days
EBS Snapshots EC2/EBS Source volume deleted (orphans)
RDS Instances RDS Stopped (storage still billed)
RDS (underutilized) RDS Max CPU ≤ 5% in 14 days
Load Balancers ELBv2 No registered targets
NAT Gateways VPC Zero outbound traffic in 48h
CloudWatch Log Groups CloudWatch No retention policy
S3 Buckets S3 No lifecycle configuration
Lambda Functions Lambda Zero invocations in 7 days
EFS File Systems EFS Zero I/O in 48h
DynamoDB Tables DynamoDB Provisioned, utilization < 10% in 7 days
ElastiCache, Redshift, OpenSearch, MSK, FSx, DocumentDB, Neptune, MQ, WorkSpaces, VPN, Transit Gateway, Kinesis Various Idle (zero activity in 48h)

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, the summary or the report DTO.