Sprout

Sprout is a small HTTP service that reports a machine's GPUs, VRAM, memory, and CPU. LettuceAI queries it to work out which models a remote or headless machine can run, and how to spread them across multiple GPUs.

GPU detection is split by vendor: NVML for NVIDIA, Vulkan for AMD and Intel, and Metal for Apple. It uses only the drivers already on the machine and ships as a single binary.

Installation

Download a prebuilt binary for your platform from the releases page, or build from source with a Rust toolchain:

cargo build --release

The binary is written to target/release/sprout.

Usage

Start the server:

sprout

The first run creates a config file, generates a 32-character API key, and prints it to the terminal. Requests to /specs carry that key as a bearer token:

curl -H "Authorization: Bearer <key>" http://127.0.0.1:8477/specs

Sprout serves three routes. GET /ping returns its name and version for discovery and GET /health is a liveness check; both are public. GET /specs returns the hardware snapshot and requires the key:

{
  "schemaVersion": 1,
  "hostname": "megalith",
  "os": "linux",
  "arch": "x86_64",
  "availableMemoryBytes": 6819835904,
  "totalMemoryBytes": 16560168960,
  "cpuName": "Intel(R) Core(TM) i7-10700K CPU @ 3.80GHz",
  "cpuCores": 16,
  "unifiedMemory": false,
  "gpus": [
    {
      "index": 0,
      "name": "Vulkan0",
      "description": "NVIDIA GeForce RTX 4060",
      "vendor": "nvidia",
      "backend": "Vulkan",
      "memoryTotal": 8585740288,
      "memoryFree": 6839926784,
      "deviceType": "Gpu"
    }
  ]
}

Every memory value is in bytes. Each vendor is probed independently, so a GPU whose driver is missing is simply omitted; a machine with no detectable GPU reports an empty gpus list and the rest of the report still works.

Running as a service

On Linux, scripts/install.sh builds the release binary, installs it to ~/.local/bin, and registers a systemd user service:

./scripts/install.sh

It prints the API key and config path when it finishes. Manage the service with the usual commands:

systemctl --user status sprout
journalctl --user -u sprout -f
systemctl --user restart sprout

scripts/uninstall.sh removes the binary and service. To keep the service running while you are logged out, enable lingering once:

sudo loginctl enable-linger "$USER"

On other platforms, run the binary under any process supervisor, or detach it directly:

nohup sprout >/tmp/sprout.log 2>&1 &   # Linux, macOS
start "" /b sprout.exe                 # Windows

Configuration

Sprout reads config.toml from the platform config directory, which you can override with --config <path>:

• Linux: ~/.config/sprout/config.toml
• macOS: ~/Library/Application Support/sprout/config.toml
• Windows: %APPDATA%\sprout\config.toml

host = "127.0.0.1"
port = 8477
api_key = "..."
require_auth = true

Set host to 0.0.0.0 to accept connections from other machines. Clearing api_key regenerates it on the next start, and setting require_auth to false serves /specs without a token. The file is created with 600 permissions because it holds the key; restart Sprout after editing it.

License

AGPL-3.0-only. See LICENSE.