Go

The best way to run Go programs in WasmEdge is to compile Go source code to WebAssembly using TinyGo. In this article, we will show you how.

Install TinyGo

You must have Go already installed on your machine before installing TinyGo. Go v1.17 or above is recommended. For Ubuntu or other Debian-based Linux systems on x86 processors, you could use the following command line to install TinyGo. For other platforms, please refer to TinyGo docs.

wget https://github.com/tinygo-org/tinygo/releases/download/v0.21.0/tinygo_0.21.0_amd64.deb
sudo dpkg -i tinygo_0.21.0_amd64.deb`

Next, run the following command line to check out if the installation is successful.

$ tinygo version
tinygo version 0.21.0 linux/amd64 (using go version go1.16.7 and LLVM version 11.0.0)

Hello world

The simple Go app has a main() function to print a message to the console. The source code in main.go file is as follows.

package main
func main() {
  println("Hello TinyGo from WasmEdge!")
}

Inside the main() function, you can use Go standard API to read / write files, and access command line arguments and env variables.

Hello world: Compile and build

Next, compile the main.go program to WebAssembly using TinyGo.

tinygo build -o hello.wasm -target wasi main.go

You will see a file named hello.wasm in the same directory. This is a WebAssembly bytecode file.

Hello world: Run

You can run it with the WasmEdge CLI.

$ wasmedge hello.wasm
Hello TinyGo from WasmEdge!

A simple function

The second example is a Go function that takes a call parameter to compute a fibonacci number. However, in order for the Go application to set up proper access to the OS (e.g., to access the command line arguments), you must include an empty main() function in the source code.

package main
func main(){
}
//export fibArray
func fibArray(n int32) int32{
  arr := make([]int32, n)
  for i := int32(0); i < n; i++ {
    switch {
    case i < 2:
      arr[i] = i
    default:
      arr[i] = arr[i-1] + arr[i-2]
    }
  }
  return arr[n-1]
}

A simple function: Compile and build

Next, compile the main.go program to WebAssembly using TinyGo.

tinygo build -o fib.wasm -target wasi main.go

You will see a file named fib.wasm in the same directory. This is a WebAssembly bytecode file.

A simple function: Run

You can run it with the WasmEdge CLI in its --reactor mode. The command line arguments that follow the wasm file are the function name and its call parameters.

$ wasmedge --reactor fib.wasm fibArray 10
34

Improve performance

To achieve native Go performance for those applications, you could use the wasmedgec command to AOT compile the wasm program, and then run it with the wasmedge command.

$ wasmedgec hello.wasm hello.wasm
$ wasmedge hello.wasm
Hello TinyGo from WasmEdge!

For the --reactor mode,

$ wasmedgec fib.wasm fib.wasm
$ wasmedge --reactor fib.wasm fibArray 10
34