wasi-grpc 0.1.0

# wasi-grpc

Enables **gRPC clients** to work inside **Spin** components using [`wasi-hyperium`](https://github.com/fermyon/wasi-hyperium) and the [`spin-rust-sdk`](https://github.com/fermyon/spin-rust-sdk).

Spin is a fast, secure WebAssembly framework for serverless apps. This project extends Spin's capabilities by enabling components to make outbound gRPC requests, bridging the gap between Wasm sandboxing and modern microservice communication.

## 🚀 Features

- 🧩 **gRPC over HTTP/2** support inside Spin apps
- 🔐 Compatible with the Spin sandbox security model
- 🦀 Built with `wasi-hyperium` and `tonic`
- 🌍 Works with most standard gRPC services
- 🧪 Great for calling internal microservices or public gRPC APIs from Spin

## 🛠️ Usage

### 1. Add required dependencies to your Cargo.toml

```toml
[dependencies]
anyhow = "1"
futures = "0.3.28"
prost = "0.13.5"
wasi-grpc = "0.1.0"
spin-sdk =  "4.0.0"
tonic = { version = "0.13.1", features = ["codegen", "prost", "router"], default-features = false}
```

### 2. Generate gRPC client code with `tonic-build`

In `build.rs`:

```rust
fn main() {
    tonic_build::configure()
        .type_attribute("routeguide.Point", "#[derive(Hash)]")
        .build_transport(false)
        .compile_protos(&["route_guide.proto"], &[""])
        .unwrap();
}
```

And in `Cargo.toml`:

```toml
[build-dependencies]
tonic-build = { version = "0.13.1", features = ["prost"] }
```

### 3. Call your gRPC service from a Spin component

```rust
let endpoint = WasiGrpcEndpoint::new(endpoint_uri);
let mut client = RouteGuideClient::new(endpoint);

let response = client.get_feature(Request::new(Point {
    latitude: 409_146_138,
    longitude: -746_188_906,
})).await?;
```

## 🔒 Spin Notes

This project assumes execution in a **Spin-compliant runtime** that allows outbound networking via Spin's capability-based model. Ensure your `spin.toml` includes the appropriate `allowed_outbound_hosts` granting outbound access to your gRPC service's endpoint.