Deep Dive
Air - Deep Dive
Technical architecture of the Air background daemon: gRPC service definitions, update pipeline, authentication, indexing, and connection lifecycle with Mountain.
Air is a standalone Rust binary structured around a central gRPC server that receives task delegation from Mountain. It runs as a persistent sidecar process alongside Mountain, offloading resource-intensive operations so the editor remains responsive. Internal modules handle distinct responsibilities: updates, downloads, authentication, and health monitoring.
Key Modules
| Path | Description |
|---|---|
Source/Binary.rs | Binary entry point; bootstraps Tokio runtime and starts daemon |
Source/Initialize/ | Startup sequence: config loading, server binding, state init |
Source/Vine/ | gRPC server implementation using tonic; routes incoming calls |
Source/Updates/ | Update lifecycle: check, download, verify, apply patches |
Source/Downloader/ | Resilient download manager with pause, resume, and retry |
Source/Authentication/ | Cryptographic signing of binaries and secure token storage |
Source/HTTP/ | HTTP client configured to use Mist local DNS resolver |
Source/HealthCheck/ | Self-monitoring and watchdog for process health |
Source/Metrics/ | Telemetry collection and reporting to Mountain |
Source/Logging/ | Structured tracing output via the tracing crate |
Source/CLI/ | Command-line argument parsing for daemon startup options |
Source/Resilience/ | Retry logic and circuit breakers for network operations |
Source/Security/ | Signature verification and secure storage utilities |
Source/Configuration/ | Runtime configuration loading and hot-reload support |
Source/Library.rs | Library root exposing the public API for integration tests |
Data Flow
The following sequence shows how Mountain delegates an update task to Air and receives progress notifications.
Port allocation:
- Air listens on
[::1]:50053(reserved for the Air daemon). - Cocoon uses
[::1]:50052(the VS Code extension host).
Integration Points
| Connecting Element | Direction | Mechanism | Description |
|---|---|---|---|
| Mountain | Bidirectional | gRPC over Vine/Air.proto | Mountain delegates tasks; Air streams progress events back |
| Mist | Inbound | Local DNS resolver | Air configures its HTTP client to use Mist’s DNS for secure resolution |
| Vine | Inbound | Protocol definition | Air.proto defines service contracts; tonic generates Rust server stubs |
Configuration
| Parameter | Source | Description |
|---|---|---|
| Bind address | CLI flag / environment | Default [::1]:50053; overridable for testing |
| Update server URL | Configuration file | Base URL for checking and downloading updates |
| Download cache directory | Configuration file | Where partial downloads are stored for resume |
| Health check interval | Configuration file | Frequency of self-monitoring checks |
| Log level | RUST_LOG environment variable | Tracing filter for structured log output |
Air is spawned automatically by Mountain at startup. Mountain detects whether an Air process is already running before spawning a new instance.