Plugins

The nautilus-plugin crate defines the artifact contract for NautilusTrader plug-ins: an independently compiled Rust cdylib that identifies itself with a versioned manifest and exchanges values across a C-ABI boundary. The crate covers artifact identity and the boundary primitives only. It does not load, register, or run plug-ins; the loading host is an internal Nautilus deployment detail and is not part of this repository.

:::warning The plug-in ABI is early alpha and the contract is unstable. Pin plug-in builds to the matching nautilus-plugin version. :::

Artifact contract

A plug-in is a Rust cdylib that exports a single entry symbol, nautilus_plugin_init. The nautilus_plugin! macro generates that symbol together with the static manifest carrying the build identity:

nautilus_plugin::nautilus_plugin! {
    name: "example-plugin",
    vendor: "Nautech",
    version: env!("CARGO_PKG_VERSION"),
}

name and version are required, vendor defaults to an empty string. Invoke the macro once per artifact at module scope, set crate-type = ["cdylib"] in the artifact's Cargo.toml, and depend on the matching nautilus-plugin version.

Manifest compatibility

nautilus_plugin_init takes an opaque host pointer and returns a PluginManifest held in process-lifetime storage, or null when the host pointer is null or the call panics. PluginManifest::validate checks the invariants a host relies on before registration. It reports every structural problem it finds and fails when:

• abi_version does not equal NAUTILUS_PLUGIN_ABI_VERSION, or build_id.schema_version does not equal PLUGIN_BUILD_ID_VERSION.
• plugin_name or plugin_version is empty.
• Any manifest string is malformed: a null pointer with non-zero length, or bytes that are not valid UTF-8.
• build_id.precision_mode or build_id.fixed_precision differs from the host build.

Precision is validated because it changes model type layout across the boundary. The remaining build identity fields (nautilus-plugin version, rustc version, target triple, and build profile) are diagnostic.

Boundary rules

Only the #[repr(C)] types in nautilus_plugin::boundary, and #[repr(C)] types built from them, may appear in a signature that crosses the boundary. String, Vec, and Box<dyn Trait> rely on Rust's unstable ABI and must never cross it. Panics must not unwind across the boundary either; the generated entry symbol catches them and returns null.

Under the current ABI, plug-ins are not unloaded, so manifest storage stays valid for the life of the process.

See the crate docs for the boundary and manifest types.