Crate zlayer_sdk 

ZLayer SDK for building WASM plugins in Rust.

This crate provides type-safe bindings to ZLayer host functions and convenient macros for implementing plugins.

Example

#![no_std]
extern crate alloc;

use alloc::string::String;
use alloc::vec::Vec;
use zlayer_sdk::bindings::{
    export_handler,
    exports::zlayer::plugin::handler::{
        Guest, Capabilities, HandleResult, InitError, PluginInfo, PluginRequest,
    },
    zlayer::plugin::{
        config, logging,
        plugin_metadata::Version,
        request_types::PluginResponse,
    },
};

struct MyPlugin;

impl Guest for MyPlugin {
    fn init() -> Result<Capabilities, InitError> {
        logging::info("Initializing...");
        Ok(Capabilities::CONFIG | Capabilities::LOGGING)
    }

    fn info() -> PluginInfo {
        PluginInfo {
            id: String::from("my:plugin"),
            name: String::from("My Plugin"),
            version: Version { major: 0, minor: 1, patch: 0, pre_release: None },
            description: String::from("A custom plugin"),
            author: String::from("Author"),
            license: None,
            homepage: None,
            metadata: Vec::new(),
        }
    }

    fn handle(request: PluginRequest) -> HandleResult {
        logging::info("Handling request");
        HandleResult::Response(PluginResponse {
            status: 200,
            headers: Vec::new(),
            body: b"Hello from ZLayer!".to_vec(),
        })
    }

    fn shutdown() {
        logging::info("Shutting down...");
    }
}

// Note: `with_types_in` is required when using the SDK from an external crate
export_handler!(MyPlugin with_types_in zlayer_sdk::bindings);

Features

• Type-safe bindings - Generated from WIT definitions
• Host function access - Config, KV storage, logging, secrets, metrics
• HTTP capabilities - Make outbound HTTP requests
• no_std compatible - Minimal runtime dependencies

no_std Support

This crate is no_std by default for WASM plugin compilation. Enable the std feature for native testing or non-WASM targets.

Modules

bindings

Generated bindings from WIT definitions.

config

Configuration access for plugins.

kv

Key-value storage for plugin state.

log

Structured logging for plugins.

metadata

Helper module for working with plugin metadata.

metrics

Metrics emission for observability.

prelude

Prelude module for convenient imports.

response

Helper module for building plugin responses.

secrets

Secure secret access for plugins.

Macros

zlayer_plugin

Register a plugin implementation with the ZLayer runtime.

Structs

ConfigError

Error returned by config operations

SecretError

Error returned by secret operations

Enums

KvError

Error returned by key-value operations

Traits

ZLayerPlugin

Trait for implementing ZLayer plugins.

Functions

kv_pair

Create a KeyValue pair.

version

Create a Version struct.

version_pre

Create a Version struct with pre-release tag.