docker-volume-backup/internal/storage/azure/azure.go

161 lines
4.4 KiB
Go
Raw Normal View History

// Copyright 2022 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package azure
import (
"bytes"
"context"
"errors"
"fmt"
"os"
"path/filepath"
"strings"
"sync"
"text/template"
"time"
"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/container"
"github.com/offen/docker-volume-backup/internal/storage"
)
type azureBlobStorage struct {
*storage.StorageBackend
client *azblob.Client
containerName string
}
// Config contains values that define the configuration of an Azure Blob Storage.
type Config struct {
AccountName string
ContainerName string
PrimaryAccountKey string
Endpoint string
RemotePath string
}
// NewStorageBackend creates and initializes a new Azure Blob Storage backend.
func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
endpointTemplate, err := template.New("endpoint").Parse(opts.Endpoint)
if err != nil {
return nil, fmt.Errorf("NewStorageBackend: error parsing endpoint template: %w", err)
}
var ep bytes.Buffer
if err := endpointTemplate.Execute(&ep, opts); err != nil {
return nil, fmt.Errorf("NewStorageBackend: error executing endpoint template: %w", err)
}
normalizedEndpoint := fmt.Sprintf("%s/", strings.TrimSuffix(ep.String(), "/"))
var client *azblob.Client
if opts.PrimaryAccountKey != "" {
cred, err := azblob.NewSharedKeyCredential(opts.AccountName, opts.PrimaryAccountKey)
if err != nil {
return nil, fmt.Errorf("NewStorageBackend: error creating shared key Azure credential: %w", err)
}
client, err = azblob.NewClientWithSharedKeyCredential(normalizedEndpoint, cred, nil)
if err != nil {
return nil, fmt.Errorf("NewStorageBackend: error creating Azure client: %w", err)
}
} else {
cred, err := azidentity.NewManagedIdentityCredential(nil)
if err != nil {
return nil, fmt.Errorf("NewStorageBackend: error creating managed identity credential: %w", err)
}
client, err = azblob.NewClient(normalizedEndpoint, cred, nil)
if err != nil {
return nil, fmt.Errorf("NewStorageBackend: error creating Azure client: %w", err)
}
}
storage := azureBlobStorage{
client: client,
containerName: opts.ContainerName,
StorageBackend: &storage.StorageBackend{
DestinationPath: opts.RemotePath,
Log: logFunc,
},
}
return &storage, nil
}
// Name returns the name of the storage backend
func (b *azureBlobStorage) Name() string {
return "Azure"
}
// Copy copies the given file to the storage backend.
func (b *azureBlobStorage) Copy(file string) error {
fileReader, err := os.Open(file)
if err != nil {
return fmt.Errorf("(*azureBlobStorage).Copy: error opening file %s: %w", file, err)
}
_, err = b.client.UploadStream(
context.Background(),
b.containerName,
filepath.Join(b.DestinationPath, filepath.Base(file)),
fileReader,
nil,
)
if err != nil {
return fmt.Errorf("(*azureBlobStorage).Copy: error uploading file %s: %w", file, err)
}
return nil
}
// Prune rotates away backups according to the configuration and provided
// deadline for the Azure Blob storage backend.
func (b *azureBlobStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
lookupPrefix := filepath.Join(b.DestinationPath, pruningPrefix)
pager := b.client.NewListBlobsFlatPager(b.containerName, &container.ListBlobsFlatOptions{
Prefix: &lookupPrefix,
})
var matches []string
var totalCount uint
for pager.More() {
resp, err := pager.NextPage(context.Background())
if err != nil {
return nil, fmt.Errorf("(*azureBlobStorage).Prune: error paging over blobs: %w", err)
}
for _, v := range resp.Segment.BlobItems {
totalCount++
if v.Properties.LastModified.Before(deadline) {
matches = append(matches, *v.Name)
}
}
}
stats := storage.PruneStats{
Total: totalCount,
Pruned: uint(len(matches)),
}
if err := b.DoPrune(b.Name(), len(matches), int(totalCount), func() error {
wg := sync.WaitGroup{}
wg.Add(len(matches))
var errs []error
for _, match := range matches {
name := match
go func() {
_, err := b.client.DeleteBlob(context.Background(), b.containerName, name, nil)
if err != nil {
errs = append(errs, err)
}
wg.Done()
}()
}
wg.Wait()
if len(errs) != 0 {
return errors.Join(errs...)
}
return nil
}); err != nil {
return &stats, err
}
return &stats, nil
}