Vex

A Docker-like CLI for saving, sharing, and launching QEMU virtual machines.

Vex turns complex qemu-system-* invocations into named configurations you can save, edit, distribute, and run by name. It targets embedded development, firmware development, and OS development workflows where the same handful of QEMU recipes get typed (and mistyped) every day.

Features

Capability	Commands	Phase
Local config management	save, list, print, rm, rename, edit, exec	1
Shell completions	completions	1
Git remote distribution	push, pull	2
Resource binding	save --image/--firmware/--resource, resource	3
Resource cache	cache	3
Vex Hub (HTTP read-only client)	hub	3
Interactive TUI	tui	4

Installation

Install the vex binary into ~/.cargo/bin (already on PATH for a standard Rust setup):

cargo install --path .
vex tui

Or build without installing — the binary lands at target/release/vex:

cargo build --release

Requires Rust 1.85+ (edition 2024).

Quickstart

Local — save and run:

vex save my-vm qemu-system-x86_64 -m 2G -smp 4
vex list
vex exec my-vm

Team — push to a Git registry, pull elsewhere:

# Publisher: create a config, then push it
export VEX_REMOTE_URL=git@github.com:my-team/vex-registry.git
vex save dev-box qemu-system-aarch64 -m 4G
vex push team/dev-box:v1 dev-box

# Teammate: pull and run
export VEX_REMOTE_URL=git@github.com:my-team/vex-registry.git
vex pull team/dev-box:v1
vex exec dev-box

Public — install from a Vex Hub (see Vex Hub):

export VEX_HUB_URL=https://hub.example.com/
vex hub install team/demo-arm64:v1 --fetch-resources

Interactive TUI

vex tui

Two-pane Browse mode for navigating and launching saved configurations, in-place e / n Edit mode with a Snippets drawer, and a full-screen Library mode (Ctrl+L) for managing the user snippet library. Builtin snippets are read-only; user overrides persist atomically to ~/.vex/snippets.json.

Full keybindings, workflows, and screenshots: docs/TUI.md.

Resource binding

A configuration’s args may reference external files (disk images, firmware blobs, …) declared as resources. Resources are bound by key, validated on save, and substituted into args at exec time using ${res:KEY}.

vex save vm1 qemu-system-x86_64 \
    --image disk=./ubuntu.qcow2 \
    -m 2G \
    -drive 'file=${res:disk},format=qcow2'

vex resource list vm1
vex exec vm1

${res:KEY} placeholders only match keys matching [A-Za-z_][A-Za-z0-9_]*; other forms are left as literal text. Unknown keys at exec time raise UnknownResourceReference. By default, vex save captures sha256 + size; add --no-checksum to skip when files are large or absent locally.

Resource cache

vex pull --fetch-resources and vex hub install --fetch-resources write downloaded files into a unified content-addressed cache at <config_dir parent>/resources (default: ~/.vex/resources).

vex cache list
vex cache info <hash-or-prefix>
vex cache rm <hash> [--force]
vex cache prune [--dry-run]

Hash arguments accept the full 64 hex characters or any prefix of at least 4 characters. Override the cache location with VEX_RESOURCE_CACHE_DIR.

Vex Hub

The Vex Hub is a read-only HTTP service that distributes curated configurations and resource metadata. It serves the same PublishedConfig v2 format that vex push writes to a Git remote — Git remotes and the Hub are complementary, not competing.

vex hub list --kind demo
vex hub search arm64
vex hub info team/demo-arm64:v1
vex hub install team/demo-arm64:v1 --as my-arm --fetch-resources

Protocol: docs/HUB_PROTOCOL.md.

Note: There is no officially deployed Hub server yet. The default VEX_HUB_URL (hub.vex.example) uses the RFC 2606 reserved TLD and is intentionally non-resolvable. To use vex hub, point VEX_HUB_URL at a server that implements the protocol above.

Environment variables

Variable	Purpose	Default
VEX_CONFIG_DIR	Local config storage directory	~/.vex/configs
VEX_REMOTE_URL	Git remote registry URL or local path	(none, push/pull errors out)
VEX_REMOTE_BRANCH	Branch used for remote distribution	main
VEX_REMOTE_GIT_NAME	Git author name for vex push commits	Vex CLI
VEX_REMOTE_GIT_EMAIL	Git author email for vex push commits	vex@example.invalid
VEX_RESOURCE_CACHE_DIR	Resource cache directory	<config_dir parent>/resources
VEX_HUB_URL	Vex Hub base URL	https://hub.vex.example/ (placeholder)

Configuration file format

Each saved configuration is a JSON file at <VEX_CONFIG_DIR>/<name>.json. The schema is the QemuConfig struct in src/config/types.rs:

{
  "qemu_bin": "qemu-system-x86_64",
  "args": ["-m", "2G", "-drive", "file=${res:disk}"],
  "desc": "Ubuntu development VM",
  "qemu_version": "9.0.1",
  "resources": {
    "disk": {
      "path": "/var/cache/vex/aa/bbbb...",
      "kind": "image",
      "sha256": "aabb...",
      "size": 1073741824,
      "url": "https://example.com/ubuntu.qcow2"
    }
  }
}

desc, qemu_version, resources, and the optional fields inside each ResourceRef are omitted from output when unset.

Documentation

• docs/TUI.md — Interactive TUI manual (keybindings, workflows, screenshots).
• docs/HUB_PROTOCOL.md — Hub HTTP protocol spec.
• CHANGELOG.md — Release history.

Roadmap

• ✅ Phase 1 (0.1.0): Local config management.
• ✅ Phase 2 (0.2.0): Git-remote distribution, PublishedConfig v1.
• ✅ Phase 3 (0.3.0): Resource binding, content-addressed cache, Vex Hub HTTP client, PublishedConfig v2.
• ✅ Phase 4 (0.4.x): Interactive TUI — Browse, Edit, Snippets drawer, Library mode.
• Future: reference Hub server, web UI, resource signing, plugins.

License

See LICENSE.