bun-prewarm

Prewarm Bun runtime state inside a Firecracker VM before snapshotting.

Purpose

This package warms Bun-related filesystem, binary, and runtime state so that after snapshot restore, Bun startup and first-execution latency are lower.

Installation

``sh
npm install -g @insanitybit/bun-prewarm
`

Usage

Run explicitly during VM snapshot build:

`sh
bun-prewarm


then snapshot the VM


`

What it does

1. Runs bun --version to fault the Bun binary into memory
2. Executes a small JS workload under Bun to warm parsing and runtime
3. Runs bun install --no-save to warm package manager code paths

Requirements

- Bun must be installed and available on $PATH`
- Linux environment (Firecracker VM)
- Node.js 18+ (for running the prewarm script itself)