axum-core-async-performance

What problem does it solve?

This Skill prevents slow, frozen, or “requests hanging forever” Axum services caused by blocking calls inside async handlers, incorrect offloading, unsafe non-Send values across .await, and misconfigured database pooling.

Core Features & Use Cases

• Offload CPU-bound and blocking work correctly: Use tokio::task::spawn_blocking for synchronous/CPU-heavy closures while keeping handlers non-blocking.
• Diagnose and eliminate runtime starvation: Identify blocking operations (std thread sleep, std fs, blocking drivers, CPU loops) and replace them with tokio async equivalents.
• Avoid Handler trait failures from !Send futures: Scope std::sync::MutexGuard and other !Send values so they do not live across .await.
• Make database pooling fail fast: Build one sqlx pool at startup, reuse it via Axum state, and always set acquire_timeout to avoid indefinite hangs.

Quick Start

Tell the AI: “Given my Axum handler is slow or freezes under concurrent load, show me exactly which blocking calls and !Send problems I likely have, then refactor it to use tokio async APIs, spawn_blocking where needed, and a properly sized sqlx pool with acquire_timeout.”