Vine - Deep Dive

Vine is the contract-first gRPC protocol layer defining strongly-typed inter-process communication contracts between Mountain, Cocoon, Grove, and Air.

Architecture 🏗️

The proto files are the source of truth. Generated Rust code from tonic/prost is used by Mountain for the server implementation and by Cocoon/Grove for client stubs.

Protocol Files

Proto File	Purpose
Vine.proto	Core protocol: Mountain to Cocoon commands, events, handshake
Spine.proto	Extension host coordination: action/response pattern
Grove.proto	Grove-specific: WASM host function calls, extension lifecycle
Air.proto	Air daemon: updates, downloads, health checks

Modules

| Path | | -------------------------------------------------------- | ----------------------------------------------- | | Source/lib.rs - Library root, re-exports generated types | | Source/Message/ | Structured message types shared across services | | Source/Service/ | gRPC service trait implementations | | Source/Client/ | Protocol client helpers for consumer crates |

Communication Patterns 📡

Pattern	Use Case
Unary RPC	Commands and queries
Server streaming	Mountain streams terminal output, diagnostics to Cocoon
Client streaming	Cocoon sends batched registration at startup
Bidirectional streaming	Spine protocol real-time extension host coordination

Ports and Transport 🌐

Service	Port	Transport
Vine/Cocoon	50052	TCP loopback
Air daemon	50053	TCP loopback
TLS	Disabled	Loopback only, Mist DNS provides network boundary

Client Implementations 📱

Element	Implementation
Cocoon	@grpc/grpc-js Node.js client
Grove	tonic Rust client
Air daemon	tonic gRPC server (Mountain connects as client)

Request Flow Example 📋

Wind UI -> Mountain Tauri invoke (executeCommand)
  -> Mountain serializes to CommandRequest protobuf
  -> gRPC unary call to Cocoon
  -> Cocoon returns CommandResponse protobuf
  -> Mountain deserializes, sends Tauri event with result

Proto files compiled at build time by prost-build in Mountain build script.