Async Build Pipeline

Eigen's build pipeline runs asynchronously on the tokio runtime, enabling concurrent page rendering and overlapping HTTP requests.

How It Works

Pages are rendered concurrently using futures::stream::buffer_unordered with a concurrency limit of available_parallelism * 2. Shared state (data cache, asset cache, template engine) is wrapped in Arc<tokio::sync::Mutex<T>> for safe concurrent access.

Concurrency Model

• HTTP requests overlap across pages — while one page waits for a response, others can render or fetch.
• Template rendering is serialized via a mutex on minijinja::Environment (it's Send but not Sync). Each render is fast (microseconds), so this is not a bottleneck.
• File writes use tokio::fs for non-blocking I/O.
• CPU-bound work (minification, CSS parsing, image optimization) runs synchronously within async tasks — tokio handles scheduling.

Dev Server

The dev server runs builds natively on the tokio runtime. No spawn_blocking or thread bridging is needed. Dev rebuilds are sequential (single task) since they're fast enough for interactive use.

Configuration

No new configuration is needed. The concurrency limit is automatic.