44e897ddad
* Add Go as an embedding to the book Also take this time to list out all embeddings in the README of wasmtime itself.
77 lines
1.9 KiB
Markdown
77 lines
1.9 KiB
Markdown
# Go
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Wasmtime [is available as a Go
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Module](https://pkg.go.dev/github.com/bytecodealliance/wasmtime-go). This guide
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will go over adding Wasmtime to your project, and some provided examples of what
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can be done with WebAssembly modules.
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Make sure you're using Go 1.12 or later with modules support.
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## Getting started and simple example
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First up you'll want to start a new module:
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```sh
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$ mkdir hello-wasm
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$ cd hello-wasm
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$ go mod init hello-wasm
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```
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Next, copy this example WebAssembly text module into your project. It exports a
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function for calculating the greatest common denominator of two numbers.
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```wat
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{{#include ../examples/gcd.wat}}
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```
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Next, we can write our code in `main.go` which reads this file and runs it:
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```go
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package main
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import (
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"fmt"
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"github.com/bytecodealliance/wasmtime-go"
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)
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func main() {
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store := wasmtime.NewStore(wasmtime.NewEngine())
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module, err := wasmtime.NewModuleFromFile(store, "gcd.wat")
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check(err)
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instance, err := wasmtime.NewInstance(module, []*wasmtime.Extern{})
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check(err)
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gcd := instance.GetExport("gcd").Func()
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val, err := gcd.Call(6, 27)
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check(err)
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fmt.Printf("gcd(6, 27) = %d\n", val.(int32))
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}
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func check(err error) {
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if err != nil {
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panic(err)
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}
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}
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```
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And finally we can build and run it:
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```sh
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$ go run main.go
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gcd(6, 27) = 3
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```
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If this is the output you see, congrats! You've successfully ran your first
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WebAssembly code in Go!
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## More examples and contributing
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The `wasmtime` Go package [lives in its own
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repository](https://github.com/bytecodealliance/wasmtime-go) and has a [number
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of other more advanced
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examples](https://pkg.go.dev/github.com/bytecodealliance/wasmtime-go?tab=doc#pkg-examples)
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as well. Feel free to browse those, but if you find anything missing don't
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hesitate to [open an
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issue](https://github.com/bytecodealliance/wasmtime-go/issues/new) and let us
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know if you have any questions!
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