Go Template

If you are a Go programmer then Go Templates makes a lot of sense. But Helm, and Hugo are some of the more popular tools that use it, so its usage is relatively specialized. For this reason you really have to assess if there is any need.

Things to know

The language is fully described in the programming documentation. Basically, it reads text for embeds. Anytime you want to drop to code you use {{ ... }}. The output of that block is then inserted in place. Data can be accessed with $ (main object), or . (current scope). There are a relatively small set of built-ins like range, or block.

The main object ($) and all functions have to be registered directly in the go code. Meaning that different usages have very different behaviors. Sprig is a very common library of template functions that should be loaded to make the templates really useful.

Example

import (
  "github.com/Masterminds/sprig/v3"
  "html/template"
)

// This example illustrates that the FuncMap *must* be set before the
// templates themselves are loaded.
tpl := template.Must(
  template.New("base").Funcs(sprig.FuncMap()).ParseGlob("*.html")
)

template.FuncMap is a map[string]any and can be used to add any functions to the list, including internally developed ones.