wisesayingswasm

A project the demonstrates how to create a microservice as a WebAssembly binary created in Rust and have the WebAssembly binary hosted in a Deno webserver.

The Deno web server uses the get_wise_sayings() function in the WebAssembly binary to get a random wise saying.

Developer's Note
The optimal development environment in which to run this code is one that uses the Linux operating system.

Table of Contents

• Prepping the Development Environment
• Installing Deno
• Creating the WebAssembly Binary
• Getting the Deno Server Up and Running

Prepping the Development Environment

Step 1: Make sure Rust is installed on your machine by typing:

rustc --version

You'll get output similar to the following:

rustc 1.50.0 (cb75ad5db 2021-02-10)

If the call to rustc --version fails, you don't have Rust installed. Follow the instructions below and make sure you do all the tasks presented by the given installation method.

To install Rust, go here and install on Linux/MAC: ...

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

... or here to install it on Windows:

Download and run rustup-init.exe.

Step 2: Linux users, add the additional required libraries

sudo apt-get update -y

sudo apt-get install -y libssl-dev

sudo apt-get install -y pkg-config

Step 3: Get the CLI tool for generating the ts/js adapter files

cargo install wasm-bindgen-cli

Installing Deno

Linux/MAC

curl -fsSL https://deno.land/x/install/install.sh | sh

Homebrew (MAC)

brew install deno

PowerShell (Windows)

iwr https://deno.land/x/install/install.ps1 -useb | iex

Chocolatey (Windows)

choco install deno

Scoop (Windows)

scoop install deno

Cargo (Windows)

cargo install deno

Creating the WebAssembly Binary

Step 1: Get the source code for the demonstration project, Wise Sayings from GitHub

git clone https://github.com/reselbob/wisesayingswasm.git

And go to the working directory

cd wisesayingswasm

Step 2: Add the binary target

rustup target add wasm32-unknown-unknown

Step 3: Build the WebAssembly binary

cargo build --lib --target wasm32-unknown-unknown

WHERE

• cargo build is the command to invoke the compiler
• --lib indicates that you're going to build a library
• --target is the option that indicates target information
• wasm-unknown-unknown is the name of the target as well as the name of directory that will be created for the target's assets

Step 4: Generate the Javascript/TypeScript adapter files

wasm-bindgen --target deno ./target/wasm32-unknown-unknown/debug/wisesayings.wasm --out-dir ./server

WHERE

• wasm-bindgen is the command to to generate the adapter files
• --target deno indicates that the intended runtime target is Deno
• ./target/wasm32-unknown-unknown/debug/wisesayings.wasm is the location of the WebAssembly binary
• --out-dir ./server is the option that declares the output directory for the adapter files, in this case ./server. (If the directory does not exist, it will be created.)

The file output in ./server will be as follows

├── server
│   ├── main.ts
│   ├── package-lock.json
│   ├── wisesayings_bg.wasm
│   ├── wisesayings_bg.wasm.d.ts
│   ├── wisesayings.d.ts
│   └── wisesayings.js

The files, main.ts and package-lock.json exist prior as part of the demonstration project's source code.

Getting the Deno Server Up and Running

Step 1: Start the Deno server that's hosting the WebAssembly binary

deno run --allow-read --allow-net --allow-env ./server/main.ts

You'll get output similar to the following:

HTTP webserver running at Sun Mar 07 2021 18:46:34 GMT+0000 (Coordinated Universal Time).  Access it at:  http://localhost:4040/

Step 2: In a separate terminal window, call the Deno server

curl localhost:4040

You'll get a random wise saying similar to the following:

An apple a day keeps the doctor away.