rust-contract-domain-modeling

name	rust-contract-domain-modeling
description	Domain-driven modeling patterns for Axone contracts. Use when introducing domain concepts, encoding invariants, or deciding boundaries between domain, handlers, services, gateways, queries, and state.
license	BSD-3-Clause
metadata	{"author":"axone.xyz","version":"1.0"}

Rust Contract Domain Modeling

Goal

Keep business invariants in explicit domain types instead of scattering them across handlers, query builders, or storage code.

Boundary Rules

• domain/ owns business concepts and invariants.
• handlers/ decode messages, orchestrate use cases, and shape responses.
• services/ compose domain logic with environment-dependent enrichment or cross-module coordination.
• gateway/ isolates external module interaction and protocol-specific I/O.
• queries/ build external query payloads or request strings; they should not become the home of business rules.
• state/ persists data and reconstructs domain values; it should not silently redefine domain invariants.

Domain Rules

• Prefer constructors such as new or try_new that reject invalid states up front.
• Use TryFrom when validating a parsed or transport-level representation into a domain type.