Rust Multi-Surface App Architecture Blueprint (v2)

1. Context¶

This revision introduces a first-class Interface & Communication Layer that sits above the typed core and enables:

• Transport abstraction (HTTP, RPC, Events, IPC)

• Pluggable serialization formats

• Zero-config sensible defaults

• Evolution without breaking adapters

• Uniform debugging & observability

The goal is to preserve strong typing internally while allowing flexible external interfaces.

2. Updated High-Level Architecture¶

Key insight¶

Core does not depend on transport or serialization.
Interfaces mediate between typed domain and external world.

3. Interface Layer Responsibilities¶

Responsibilities¶

• Define contracts

• Map domain ↔ payload

• Handle serialization formats

• Versioning

• Validation

• Error normalization

Interface layer decomposition¶

4. Transport Layer¶

Transport becomes a thin envelope around payload.

This separation enables:

• Same payload across transports

• Adapter portability

• Better testability

5. Payload Strategy¶

DTO layer (external representation)¶

• Immutable

• Backward compatible

• Explicit versioning

• No domain invariants

Mapping layer¶

• Domain → DTO

• DTO → Domain (validation)

6. Serialization Strategy¶

Requirements¶

• Human friendly (debugging)

• Efficient

• Evolvable

• Language neutral

Multi-format SerDe model¶

Recommended defaults¶

7. Zero-Config Strategy¶

Default path¶

No configuration required for most users.

Advanced users can override:

• serialization format

• transport

• version negotiation

8. Multi-Surface Interaction Flow¶

9. Risk Mitigation Strategies¶

Risk 1 — Version drift across repos¶

Mitigation¶

• Contract-first design

• Schema version pinning

• Compatibility test suite

• Interface conformance tests

Risk 2 — Serialization overhead¶

Mitigation¶

• Binary formats for internal paths

• Zero-copy deserialization where possible

• DTO flattening

• Avoid domain → DTO churn

Risk 3 — Plugin ABI instability¶

Mitigation¶

• WASM plugin boundary

• Stable plugin API crate

• Capability-based interfaces

• Version handshake

Risk 4 — Integration complexity¶

Mitigation¶

• Meta integration repo

• Contract mocks

• Adapter test harness

• Devcontainer for reproducibility

Risk 5 — Debuggability loss with binary formats¶

Mitigation¶

• Debug mode JSON mirror

• Structured tracing payload logs

• Schema-aware inspector tools

10. Evolution Strategy¶

Layered evolution model¶

Principle¶

Each layer evolves independently with compatibility guarantees.

11. Contract Strategy¶

Contract sources¶

• OpenAPI (HTTP)

• JSON Schema (DTO)

• WIT (WASM)

• Protobuf (optional internal)

Contract sharing¶

12. Error Handling Model¶

Unified error envelope¶

{
  "type": "https://example/errors/invalid-input",
  "title": "Invalid input",
  "detail": "...",
  "trace_id": "...",
  "instance": "...",
  "metadata": {}
}

Based on RFC7807.

13. Security Strategy¶

• Capability-based plugin permissions

• Signed plugin manifests

• Schema validation

• Input sanitization

• Event provenance

• Content Security Policy (webviews)

• Transport encryption

14. Trade-off Summary¶

15. Final Opinionated Model¶

16. Future Evolution Opportunities¶

• Agent-native interfaces

• Graph-based contracts

• Schema registry

• Event mesh

• Edge adapter layer

• Semantic version negotiation

• Self-describing plugins

17. Next Possible Deep Dives¶

• DTO mapping patterns (Rust)

• WIT contract examples

• Plugin runtime protocol

• Schema evolution patterns

• Adapter test harness design

• Multi-repo CI orchestration

• Contract compatibility checker