internal/node_uuid/node_uuid.go

package node_uuid //nolint:staticcheck

import (
	"log/slog"
	"os"
	"path/filepath"

	"github.com/google/uuid"
)

const FileName = "node.uuid"

type NodeUUID struct {
	indexDir string
}

func NewNodeUUID(indexDir string) NodeUUID {
	return NodeUUID{
		indexDir: indexDir,
	}
}

func (u *NodeUUID) Get() (string, error) {
	uuid := u.loadFromDisk()

	if uuid != "" {
		slog.Info("loading existing node", "uuid", uuid)
		return uuid, nil
	}

	newUUID := u.generateNew()

	if err := u.saveToDisk(newUUID); err != nil {
		return "", err
	}

	slog.Info("assigning new node", "uuid", newUUID)
	return newUUID, nil
}

func (u *NodeUUID) loadFromDisk() string {
	path := filepath.Join(u.indexDir, FileName)

	f, err := os.ReadFile(filepath.Clean(path))
	if err != nil {
		return ""
	}

	return string(f)
}

func (u *NodeUUID) saveToDisk(uuid string) error {
	path := filepath.Join(u.indexDir, FileName)

	data := []byte(uuid)
	return os.WriteFile(path, data, 0644) //nolint:gosec
}

func (u *NodeUUID) generateNew() string {
	id := uuid.New()

	return id.String()
}