README.md

Metadata

Marshal/unmarshal Kubernetes ObjectMeta properties into/from a custom struct.

go get -u github.com/iskorotkov/metadata

Features

Supported ObjectMeta properties:

• labels
• annotations

Supported types:

• string
• bool
• time.Duration
• int, int8, int16, int32, int64
• uint, uint8, uint16, uint32, uint64
• float32, float64
• complex64, complex128
• slice of:
  • string
  • bool
  • int
  • uint
  • float32
  • float64
  • time.Duration

Examples

package main

import (
	"github.com/iskorotkov/metadata"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"reflect"
)

// Add tags to struct fields
type Data struct {
	ID     int      `annotation:"id"`
	Name   string   `annotation:"name"`
	Age    uint     `label:"age"`
	Skills []string `label:"skills"`
}

func main() {
	// Create a struct with metadata
	d := Data{
		ID:     1,
		Name:   "John",
		Age:    20,
		Skills: []string{"reading", "driving", "programming"},
	}

	// Use prefix to distinguish your labels and annotations from the ones from other tools or Kubernetes
	// Keys are formatted like this:
	// {prefix}/{name}
	prefix := "my-org.com"

	// Marshal metadata struct: add labels and annotations to ObjectMeta
	meta := v1.ObjectMeta{}
	if err := metadata.Marshal(&meta, &d, prefix); err != nil {
		panic(err)
	}

	// Unmarshall metadata: read labels and annotations and assign their values to struct fields
	d2 := Data{}
	if err := metadata.Unmarshal(meta, &d2, prefix); err != nil {
		panic(err)
	}

	// d and d2 are equal
	if !reflect.DeepEqual(d, d2) {
		panic("something doesn't work")
	}
}