Crate subako_function_sdk 

The guest side of a Subako function: a WASI preview 1 program the worker runs with argv = [package, tool], the tool’s input JSON on stdin, and the output JSON expected on stdout. Exit 0 is a result; exit 1 carries {"error": ...}, which the model reads as a failed call.

A package is written as typed functions. Each one’s name, doc comment, and input and output types become its tool, and the program prints the package’s subako-package.json when run with --subako-manifest:

use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use subako_function_sdk::{ToolError, function, package};

#[derive(Deserialize, JsonSchema)]
struct GreetInput {
    /// Who to greet.
    name: String,
}

#[derive(Serialize, JsonSchema)]
struct Greeting {
    message: String,
}

/// Greet someone by name.
#[function]
fn greet(input: GreetInput) -> Result<Greeting, ToolError> {
    Ok(Greeting { message: format!("Hello, {}!", input.name) })
}

package! {
    name: "hello",
    description: "Says hello.",
    functions: [greet],
}

The same crate built for the host prints the same manifest, so packaging needs no WebAssembly runtime: cargo run -- --subako-manifest.

Modules

http

HTTP from a guest. The worker makes the request on the guest’s behalf, under the invocation’s egress policy: which hosts it may reach and which credential headers ride along to which origins. A file body or a file response moves between the socket and the volume without passing through guest memory.

Macros

package

Declares the package: pub fn package() building it and, unless main: false, the program’s main serving it.

Structs

Function

One function a package serves as a tool.

Input

A call’s input, held until the tool says which shape it takes.

Manifest

What subako-package.json holds.

ManifestFunction

Output

A call’s result, already JSON.

Package

A package: its name, its description, and the functions it serves.

ToolError

A failure the model should read: the message is all it is told.

Constants

MANIFEST_FLAG

The argument that prints the manifest instead of calling a function.

Functions

execute

The whole call as a pure function of its arguments and stdin, so a host test drives exactly what the guest runs.

run

The guest’s main: reads argv and stdin, routes, writes stdout.

Attribute Macros

function

Makes a function a tool: its name is the tool’s, its doc comment the description the model reads, and its one argument and Ok type the input and output schemas. The function itself is left as written.