isle/go/yamlutil/yamlutil.go

package yamlutil

import (
	"errors"
	"fmt"
	"io"
	"os"

	"gopkg.in/yaml.v3"
)

// LoadYamlFile reads the file at the given path and unmarshals it into the
// given pointer.
func LoadYamlFile(into any, path string) error {
	file, err := os.Open(path)
	if err != nil {
		return fmt.Errorf("opening file: %w", err)
	}
	defer file.Close()

	if err = yaml.NewDecoder(file).Decode(into); errors.Is(err, io.EOF) {
		return nil
	} else if err != nil {
		return fmt.Errorf("decoding yaml: %w", err)
	}

	return nil
}

// WriteYamlFile encodes the given data as a yaml document, and writes it to the
// given file path, overwriting any previous data.
func WriteYamlFile(data any, path string, fileMode os.FileMode) error {

	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, fileMode)
	if err != nil {
		return fmt.Errorf("opening file: %w", err)
	}
	defer file.Close()

	if err := yaml.NewEncoder(file).Encode(data); err != nil {
		return fmt.Errorf("writing/encoding file: %w", err)
	}

	return nil
}