Building Golem Components in Go

Building Golem components having an application manifest is straightforward, just use the golem command line interface:

golem app build

If the project was created using golem app new as recommended, the golem app build command will always work as expected.

The result of the golem app build command is a WebAssembly component file ready to be uploaded to Golem. It does not have to be specified explicitly, as the golem tool will automatically find the correct file when doing for example:

golem component add

Under the hood

Building Golem components written in Go requires a series of steps.

In details, building the component requires the following steps:

Generate the Go bindings

Use the wit-bindgen tool to generate the Go bindings from the WIT files:

$ wit-bindgen tiny-go --out-dir go_example ./wit

Compile the Go code

Using the TinyGo compiler, compile the Go code into a WebAssembly module:

$ tinygo build -target=wasi -tags=purego -o go_example.module.wasm main.go

Embed the WIT files in the WebAssembly module

The following command embeds the WIT files into the WebAssembly module:

$ wasm-tools component embed ./wit go_example.module.wasm --output go_example.embed.wasm

Package the Go code into a WASM component

Finally use wasm-tools to create the WebAssembly component:

$ wasm-tools component new go_example.embed.wasm -o go_example.wasm --adapt adapters/tier1/wasi_snapshot_preview1.wasm

The adapter WASM can be downloaded from the golem-wit repository (opens in a new tab).

Reducing the component's size

The generated component's size can be reduced by stripping some parts of it using the wasm-tools strip command:

$ wasm-tools strip go_example.wasm -o go_example_stripped.wasm

Defining Components Next Steps