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Rust System Vitals

View source on GitHub

This guide walks you through building and running the Rust system vitals reference on Avocado OS. The app cross-compiles a Rust binary that reads system stats from /proc and logs structured JSON to the journal.

Prerequisites​

  • macOS 10.12+ or Linux (Ubuntu 22.04+, Fedora 39+)
  • Docker Desktop installed and running
  • The latest version of the Avocado CLI

For hardware targets, you will also need:

  • Your target device and any required accessories (SD card, USB cable, serial console adapter)
  • See the Support Matrix for your target's requirements

Initialize​

Clone the reference or initialize a new project from it:

avocado init --reference rust-vitals rust-app
cd rust-app

To target specific hardware instead of the default, pass --target:

avocado init --reference rust-vitals --target raspberrypi5 rust-app
cd rust-app

Install​

Install the SDK toolchain, extension dependencies, and runtime packages:

avocado install -f

This pulls the SDK container image and installs the Rust cross-compilation toolchain: nativesdk-rust, nativesdk-cargo, packagegroup-rust-cross-canadian-avocado-<target>, and target libraries libstd-rs and libstd-rs-dev.

Build​

Build the extensions and assemble the runtime image:

avocado build

The build step runs rust-compile.sh inside the SDK container, which:

  1. Discovers the Rust target triple from RUST_TARGET_PATH (e.g., x86_64-avocado-linux-gnu)
  2. Clears SDK-injected RUSTFLAGS to avoid conflicts
  3. Generates .cargo/config.toml with the correct --sysroot and linker flags
  4. Runs cargo build --release --target $RUST_TARGET

Then rust-install.sh locates the cross-compiled binary and copies it to /usr/bin/ref_rust in the extension sysroot.

Deploy​

QEMU​

For QEMU targets, provision and boot the VM:

avocado provision -r dev
avocado sdk run -iE vm dev

SD card targets (Raspberry Pi, Seeed reTerminal, NXP, STMicroelectronics)​

Insert your SD card and provision:

avocado provision -r dev --profile sd

Insert the SD card into the device and apply power.

USB flash targets (OnLogic)​

avocado provision -r dev --profile usb

NVIDIA Jetson​

avocado provision -r dev --profile tegraflash

Follow the USB disconnect/reconnect prompts during the flash process.

Verify​

Log in as root with an empty password. The service starts automatically on boot.

Check the service is running:

systemctl status ref-rust
journalctl -u ref-rust -f

You should see output like:

{"hostname":"avocado-qemux86-64","uptime":42,"mem_total_kb":977972,"mem_free_kb":821488,"load_1m":"0.12"}

Customize​

Edit the Rust source​

Modify ref-rust/src/main.rs to change the vitals collected or the output format.

Add Cargo dependencies​

Edit ref-rust/Cargo.toml:

[dependencies]
serde = { version = "1", features = ["derive"] }
serde_json = "1"

Rebuild after changes​

After any change, rebuild and reprovision:

avocado build
avocado provision -r dev