backup-tool/pruner/pruner.go

package pruner

import (
	"backup-tool/helpers"
	"context"
	"github.com/minio/minio-go/v7"
	"log"
	"sort"
)

func PruneFiles(bucket, endpoint string, keep int) error {
	ctx := context.Background()
	accessKeyID, secretAccessKey, err := helpers.GetCredentials()
	if err != nil {
		return err
	}
	client, err := helpers.CreateClient(accessKeyID, secretAccessKey, endpoint)
	if err != nil {
		return err
	}
	err = helpers.VerifyBucket(client, ctx, bucket)
	if err != nil {
		return err
	}

	var objects []minio.ObjectInfo
	for obj := range client.ListObjects(ctx, bucket, minio.ListObjectsOptions{}) {
		objects = append(objects, obj)
	}

	if len(objects) < keep {
		return nil
	}

	sort.Sort(BucketObjects(objects)) // last modified object will be at position 0
	for _, object := range objects[keep:] {
		err := client.RemoveObject(ctx, bucket, object.Key, minio.RemoveObjectOptions{})
		if err != nil {
			log.Printf("error deleting object %q: %s", object.Key, err.Error())
		} else {
			log.Printf("deleted object %q", object.Key)
		}
	}

	return nil
}

type BucketObjects []minio.ObjectInfo

func (b BucketObjects) Len() int           { return len(b) }
func (b BucketObjects) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
func (b BucketObjects) Less(i, j int) bool { return b[i].LastModified.After(b[j].LastModified) } // return newest object first in list