How do you marshal a line break in Go YAML?

In a golang CLI I'm programming I collect information on how to configure the tool and I marhsal that as a YAML file. However, I'm not sure how I would add line breaks to make the file more readable?

type Config struct {
	Author  string `yaml:"author"`
	License string `yaml:"license"`
	// Marhsal a line break here
	Workspace   string `yaml:"workspace"`
	Description string `yaml:"description"`
	// Marhsal a line break here
	Target string `yaml:"target"`
}

One way to implement this that allows format (and comments) is to use a template engine.

Here is a running example that generates a string with the formatted yaml, that can be then saved to a .yml file.

No additional libraries are needed and the template is included inside the go file.

package main

import (
	"bytes"
	"fmt"
	"text/template"
)

type Config struct {
	Author      string
	License     string
	Workspace   string
	Description string
	Target      string
}

const cfg_template = `
conf:
	author: {{ .Author }}
	licence: {{ .License }}

	workspace: {{ .Workspace }}
	description: {{ .Description }}

	# you can even add comments to the template
	target: {{ .Target }}

	# other hardcoded config
	foo: bar

`

func generate(config *Config) string {
	t, err := template.New("my yaml generator").Parse(cfg_template)

	if err != nil {
		panic(err)
	}

	buf := &bytes.Buffer{}
	err = t.Execute(buf, config)

	if err != nil {
		panic(err)
	}

	return buf.String()
}

func main() {
	c := Config{
		Author:      "Germanio",
		License:     "MIT",
		Workspace:   "/home/germanio/workspace",
		Description: "a cool description",
		Target:      "/home/germanio/target",
	}
	yaml := generate(&c)

	fmt.Printf("yaml:\n%s", yaml)
}

The result looks like this:

$ go run yaml_generator.go 
yaml:

conf:
        author: Germanio
        licence: MIT

        workspace: /home/germanio/workspace
        description: a cool description

        # you can even add comments to the template
        target: /home/germanio/target

        # other hardcoded config
        foo: bar

I'm sure there are better ways to implement it, just want to show a quick working example.

As empty line don't have a meaning in yaml, the default library does not create them, and does not expose an option to do so in the struct field tag.

However, if you want fine grained control of how a type is marshalled in yaml, you can always make it implements yaml.Marshaller by defining a method MarshalYAML() (interface{}, error)