WasmEdge Hyper Demo

In this project, we demonstrate how to use hyper and tokio to build async http client in WebAssembly and execute it using WasmEdge.

Why tokio in WasmEdge?

There are growing demands to perform network requests in WASM and cloud computing. But it would be inefficient to perform network requests synchronously so we need async in WASM.

As tokio is widely accepted, we can bring many projects that depend on tokio to WASM if we can port tokio into WASM. After that, the developers can have async functions in WASM as well as efficient programs.

With the help of tokio support of WasmEdge, the developers can compile the projects that use tokio into WASM and execute it using WasmEdge.

Quickstart with Docker

The easiest way to get started is to use a version of Docker Desktop or Docker CLI with Wasm support.

• Install Docker Desktop + Wasm (Beta)
• Install Docker CLI + Wasm

Build all the examples using Docker. There is no need to install Rust or WasmEdge here since Docker sets it all up for you.

docker compose build

Then, you just need to type one command to run each example.

# To run the HTTP client example
$ docker compose run --no-TTY client
... ...

# To run the HTTP server
$ docker compose run --no-TTY -p 8080:8080 server
... ...
# Test the HTTP server using curl
$ curl http://localhost:8080/echo -X POST -d "WasmEdge"
WasmEdge

# To run the Warp HTTP server
$ docker compose run --no-TTY -p 8080:8080 server-warp
... ...
# Test the HTTP server using curl
$ curl http://localhost:8080/echo -X POST -d "WasmEdge"
WasmEdge

It runs both the client and server examples in this repo. See the Dockerfile and docker-compose.yml files. The client example will run and quit upon completion. The server example starts a server that listens for incoming HTTP requests, and you can interact with it through curl.

However, if you want to build and run the examples step by step on your own system. Follow the detailed instructions below.

Prerequisites

We need install rust and wasm target first.

# install rust 
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env

# install wasm target 
rustup target add wasm32-wasi

Then install the WasmEdge. You will need all extensions to run the HTTP server with Tensorflow example.

curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash -s -- -e all
source $HOME/.wasmedge/env

Add dependencies in Cargo.toml

In this project, we add tokio and reqwest as dependencies.

[dependencies]
hyper_wasi = { version = "0.15", features = ["full"]}
tokio_wasi = { version = "1", features = ["rt", "macros", "net", "time", "io-util"]}

Examples

Details about the example apps are as below.

• HTTP client
• HTTP server
• HTTP server in warp framework
• HTTP server with Tensorflow

FAQ

use of unstable library feature 'wasi_ext'

If you are using rustc 1.64, you may encounter this error. There are two options:

1. Update rustc to newer version. Validated versions are 1.65 and 1.59.
2. Add #![feature(wasi_ext)] to the top of mio/src/lib.rs.