Handles all SPK file I/O operations: reading tar archives, extracting metadata (via sidecar JSON or in-file parsing), computing SHA-256 hashes, GPG signing and verification, and writing sidecar metadata. This adapter is isolated from the rest of the system (only depends on standard library and python-gnupg) and can be reused in any project that needs to process Synology .spk packages. It also handles partial data cleanup and concurrency-safe temp file management.

Implements the catalog generation logic for DSM compatibility. Maps architecture and language codes, determines package startability, and builds catalog entry dictionaries with metadata like version, description, and dependencies. This domain service is self-contained, using only domain primitives and a shared kernel. It can be extracted and reused for any catalog-format conversion or package metadata enrichment task.

Enforces the hexagonal architecture by testing that domain modules never import from adapters or views, and that application modules only import from domain. Uses AST parsing to verify import boundaries without runtime overhead. This pattern is non-obvious and reusable in any project that wants to maintain strict layer separation, especially when using a framework like Flask that can encourage tight coupling.