Java, Web Assembly, Docker, Kubernetes, and oh my!

readme.md

Java and Web Assembly Web Application

• This sample will use TeaVM transpiler to convert Java code into WebAssembly. Create a new TeaVM project using Maven:

  mvn -DarchetypeCatalog=local \
  -DarchetypeGroupId=org.teavm \
  -DarchetypeArtifactId=teavm-maven-webapp \
  -DarchetypeVersion=0.8.1 archetype:generate
  

• Package the .war file:

  cd teavm-maven-webapp
  mvn clean package
  

• Install Apache Tomcat:

  brew install tomcat
  

• Start Tomcat:

  brew services start tomcat
  

• Deploy the web app:

  cp target/teavm-maven-webapp-1.0-SNAPSHOT.war /opt/homebrew/opt/tomcat/libexec/webapps
  

• Access the application at http://localhost:8080/teavm-maven-webapp-1.0-SNAPSHOT/

Rust and Web Assembly Container

• Install Docker Desktop from https://docs.docker.com/desktop/install/mac-install/
• Enable containerd feature as explained at https://docs.docker.com/desktop/containerd/
• Install rustup and the latest version of Rust
• Create Rust microservice

  mkdir hello_world 
  cd hello_world 
  vi main.rs
  

  Add the following code:

  fn main() {
    println!("Hello, world!");
  }
  

• Compile and run the code

  rustc main.rs 
  ./main
  

• Install wasm-pack

  cargo install wasm-pack
  

• Build the wasm package

  wasm-pack build --target web
  

• Update Rust code in hello-wasm/src/lib.rs to this

  use wasm_bindgen::prelude::*;
  
  #[wasm_bindgen]
  extern {
      pub fn alert(s: &str);
  }
  
  #[wasm_bindgen]
  pub fn greet(name: &str) {
      alert(&format!("Hello, {}!", name));
  }
  

• Update hello-wasm/Cargo.toml to this:

  [package]
  name = "hello-wasm"
  version = "0.1.0"
  authors = ["Your Name <you@example.com>"]
  description = "A sample project with wasm-pack"
  license = "MIT/Apache-2.0"
  repository = "https://github.com/yourgithubusername/hello-wasm"
  edition = "2018"
  
  [lib]
  crate-type = ["cdylib"]
  
  [dependencies]
  wasm-bindgen = "0.2"
  

Kubernetes backend

Serverless app using Spin

• Spin