distribution/registry/storage/driver/azure/azure.go

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// Package azure provides a storagedriver.StorageDriver implementation to
// store blobs in Microsoft Azure Blob Storage Service.
package azure
import (
"bufio"
"bytes"
"context"
"fmt"
"io"
"io/ioutil"
"net/http"
"strings"
"time"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/base"
"github.com/docker/distribution/registry/storage/driver/factory"
azure "github.com/Azure/azure-sdk-for-go/storage"
)
const driverName = "azure"
const (
paramAccountName = "accountname"
paramAccountKey = "accountkey"
paramContainer = "container"
paramRealm = "realm"
maxChunkSize = 4 * 1024 * 1024
)
type driver struct {
client azure.BlobStorageClient
container string
}
type baseEmbed struct{ base.Base }
// Driver is a storagedriver.StorageDriver implementation backed by
// Microsoft Azure Blob Storage Service.
type Driver struct{ baseEmbed }
func init() {
factory.Register(driverName, &azureDriverFactory{})
}
type azureDriverFactory struct{}
func (factory *azureDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return FromParameters(parameters)
}
// FromParameters constructs a new Driver with a given parameters map.
func FromParameters(parameters map[string]interface{}) (*Driver, error) {
accountName, ok := parameters[paramAccountName]
if !ok || fmt.Sprint(accountName) == "" {
return nil, fmt.Errorf("No %s parameter provided", paramAccountName)
}
accountKey, ok := parameters[paramAccountKey]
if !ok || fmt.Sprint(accountKey) == "" {
return nil, fmt.Errorf("No %s parameter provided", paramAccountKey)
}
container, ok := parameters[paramContainer]
if !ok || fmt.Sprint(container) == "" {
return nil, fmt.Errorf("No %s parameter provided", paramContainer)
}
realm, ok := parameters[paramRealm]
if !ok || fmt.Sprint(realm) == "" {
realm = azure.DefaultBaseURL
}
return New(fmt.Sprint(accountName), fmt.Sprint(accountKey), fmt.Sprint(container), fmt.Sprint(realm))
}
// New constructs a new Driver with the given Azure Storage Account credentials
func New(accountName, accountKey, container, realm string) (*Driver, error) {
api, err := azure.NewClient(accountName, accountKey, realm, azure.DefaultAPIVersion, true)
if err != nil {
return nil, err
}
blobClient := api.GetBlobService()
// Create registry container
containerRef := blobClient.GetContainerReference(container)
if _, err = containerRef.CreateIfNotExists(); err != nil {
return nil, err
}
d := &driver{
client: blobClient,
container: container}
return &Driver{baseEmbed: baseEmbed{Base: base.Base{StorageDriver: d}}}, nil
}
// Implement the storagedriver.StorageDriver interface.
func (d *driver) Name() string {
return driverName
}
// GetContent retrieves the content stored at "path" as a []byte.
func (d *driver) GetContent(ctx context.Context, path string) ([]byte, error) {
blob, err := d.client.GetBlob(d.container, path)
if err != nil {
if is404(err) {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return nil, err
}
defer blob.Close()
return ioutil.ReadAll(blob)
}
// PutContent stores the []byte content at a location designated by "path".
func (d *driver) PutContent(ctx context.Context, path string, contents []byte) error {
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if limit := 64 * 1024 * 1024; len(contents) > limit { // max size for block blobs uploaded via single "Put Blob"
return fmt.Errorf("uploading %d bytes with PutContent is not supported; limit: %d bytes", len(contents), limit)
}
// Historically, blobs uploaded via PutContent used to be of type AppendBlob
// (https://github.com/docker/distribution/pull/1438). We can't replace
// these blobs atomically via a single "Put Blob" operation without
// deleting them first. Once we detect they are BlockBlob type, we can
// overwrite them with an atomically "Put Blob" operation.
//
// While we delete the blob and create a new one, there will be a small
// window of inconsistency and if the Put Blob fails, we may end up with
// losing the existing data while migrating it to BlockBlob type. However,
// expectation is the clients pushing will be retrying when they get an error
// response.
props, err := d.client.GetBlobProperties(d.container, path)
if err != nil && !is404(err) {
return fmt.Errorf("failed to get blob properties: %v", err)
}
if err == nil && props.BlobType != azure.BlobTypeBlock {
if err := d.client.DeleteBlob(d.container, path, nil); err != nil {
return fmt.Errorf("failed to delete legacy blob (%s): %v", props.BlobType, err)
}
}
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r := bytes.NewReader(contents)
return d.client.CreateBlockBlobFromReader(d.container, path, uint64(len(contents)), r, nil)
}
// Reader retrieves an io.ReadCloser for the content stored at "path" with a
// given byte offset.
func (d *driver) Reader(ctx context.Context, path string, offset int64) (io.ReadCloser, error) {
if ok, err := d.client.BlobExists(d.container, path); err != nil {
return nil, err
} else if !ok {
return nil, storagedriver.PathNotFoundError{Path: path}
}
info, err := d.client.GetBlobProperties(d.container, path)
if err != nil {
return nil, err
}
size := int64(info.ContentLength)
if offset >= size {
return ioutil.NopCloser(bytes.NewReader(nil)), nil
}
bytesRange := fmt.Sprintf("%v-", offset)
resp, err := d.client.GetBlobRange(d.container, path, bytesRange, nil)
if err != nil {
return nil, err
}
return resp, nil
}
// Writer returns a FileWriter which will store the content written to it
// at the location designated by "path" after the call to Commit.
func (d *driver) Writer(ctx context.Context, path string, append bool) (storagedriver.FileWriter, error) {
blobExists, err := d.client.BlobExists(d.container, path)
if err != nil {
return nil, err
}
var size int64
if blobExists {
if append {
blobProperties, err := d.client.GetBlobProperties(d.container, path)
if err != nil {
return nil, err
}
size = blobProperties.ContentLength
} else {
err := d.client.DeleteBlob(d.container, path, nil)
if err != nil {
return nil, err
}
}
} else {
if append {
return nil, storagedriver.PathNotFoundError{Path: path}
}
err := d.client.PutAppendBlob(d.container, path, nil)
if err != nil {
return nil, err
}
}
return d.newWriter(path, size), nil
}
// Stat retrieves the FileInfo for the given path, including the current size
// in bytes and the creation time.
func (d *driver) Stat(ctx context.Context, path string) (storagedriver.FileInfo, error) {
// Check if the path is a blob
if ok, err := d.client.BlobExists(d.container, path); err != nil {
return nil, err
} else if ok {
blob, err := d.client.GetBlobProperties(d.container, path)
if err != nil {
return nil, err
}
mtim, err := time.Parse(http.TimeFormat, blob.LastModified)
if err != nil {
return nil, err
}
return storagedriver.FileInfoInternal{FileInfoFields: storagedriver.FileInfoFields{
Path: path,
Size: int64(blob.ContentLength),
ModTime: mtim,
IsDir: false,
}}, nil
}
// Check if path is a virtual container
virtContainerPath := path
if !strings.HasSuffix(virtContainerPath, "/") {
virtContainerPath += "/"
}
containerRef := d.client.GetContainerReference(d.container)
blobs, err := containerRef.ListBlobs(azure.ListBlobsParameters{
Prefix: virtContainerPath,
MaxResults: 1,
})
if err != nil {
return nil, err
}
if len(blobs.Blobs) > 0 {
// path is a virtual container
return storagedriver.FileInfoInternal{FileInfoFields: storagedriver.FileInfoFields{
Path: path,
IsDir: true,
}}, nil
}
// path is not a blob or virtual container
return nil, storagedriver.PathNotFoundError{Path: path}
}
// List returns a list of the objects that are direct descendants of the given
// path.
func (d *driver) List(ctx context.Context, path string) ([]string, error) {
if path == "/" {
path = ""
}
blobs, err := d.listBlobs(d.container, path)
if err != nil {
return blobs, err
}
list := directDescendants(blobs, path)
if path != "" && len(list) == 0 {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return list, nil
}
// Move moves an object stored at sourcePath to destPath, removing the original
// object.
func (d *driver) Move(ctx context.Context, sourcePath string, destPath string) error {
sourceBlobURL := d.client.GetBlobURL(d.container, sourcePath)
err := d.client.CopyBlob(d.container, destPath, sourceBlobURL)
if err != nil {
if is404(err) {
return storagedriver.PathNotFoundError{Path: sourcePath}
}
return err
}
return d.client.DeleteBlob(d.container, sourcePath, nil)
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(ctx context.Context, path string) error {
ok, err := d.client.DeleteBlobIfExists(d.container, path, nil)
if err != nil {
return err
}
if ok {
return nil // was a blob and deleted, return
}
// Not a blob, see if path is a virtual container with blobs
blobs, err := d.listBlobs(d.container, path)
if err != nil {
return err
}
for _, b := range blobs {
if err = d.client.DeleteBlob(d.container, b, nil); err != nil {
return err
}
}
if len(blobs) == 0 {
return storagedriver.PathNotFoundError{Path: path}
}
return nil
}
// URLFor returns a publicly accessible URL for the blob stored at given path
// for specified duration by making use of Azure Storage Shared Access Signatures (SAS).
// See https://msdn.microsoft.com/en-us/library/azure/ee395415.aspx for more info.
func (d *driver) URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) {
expiresTime := time.Now().UTC().Add(20 * time.Minute) // default expiration
expires, ok := options["expiry"]
if ok {
t, ok := expires.(time.Time)
if ok {
expiresTime = t
}
}
return d.client.GetBlobSASURI(d.container, path, expiresTime, "r")
}
// Walk traverses a filesystem defined within driver, starting
// from the given path, calling f on each file
func (d *driver) Walk(ctx context.Context, path string, f storagedriver.WalkFn) error {
return storagedriver.WalkFallback(ctx, d, path, f)
}
// directDescendants will find direct descendants (blobs or virtual containers)
// of from list of blob paths and will return their full paths. Elements in blobs
// list must be prefixed with a "/" and
//
// Example: direct descendants of "/" in {"/foo", "/bar/1", "/bar/2"} is
// {"/foo", "/bar"} and direct descendants of "bar" is {"/bar/1", "/bar/2"}
func directDescendants(blobs []string, prefix string) []string {
if !strings.HasPrefix(prefix, "/") { // add trailing '/'
prefix = "/" + prefix
}
if !strings.HasSuffix(prefix, "/") { // containerify the path
prefix += "/"
}
out := make(map[string]bool)
for _, b := range blobs {
if strings.HasPrefix(b, prefix) {
rel := b[len(prefix):]
c := strings.Count(rel, "/")
if c == 0 {
out[b] = true
} else {
out[prefix+rel[:strings.Index(rel, "/")]] = true
}
}
}
var keys []string
for k := range out {
keys = append(keys, k)
}
return keys
}
func (d *driver) listBlobs(container, virtPath string) ([]string, error) {
if virtPath != "" && !strings.HasSuffix(virtPath, "/") { // containerify the path
virtPath += "/"
}
out := []string{}
marker := ""
containerRef := d.client.GetContainerReference(d.container)
for {
resp, err := containerRef.ListBlobs(azure.ListBlobsParameters{
Marker: marker,
Prefix: virtPath,
})
if err != nil {
return out, err
}
for _, b := range resp.Blobs {
out = append(out, b.Name)
}
if len(resp.Blobs) == 0 || resp.NextMarker == "" {
break
}
marker = resp.NextMarker
}
return out, nil
}
func is404(err error) bool {
statusCodeErr, ok := err.(azure.AzureStorageServiceError)
return ok && statusCodeErr.StatusCode == http.StatusNotFound
}
type writer struct {
driver *driver
path string
size int64
bw *bufio.Writer
closed bool
committed bool
cancelled bool
}
func (d *driver) newWriter(path string, size int64) storagedriver.FileWriter {
return &writer{
driver: d,
path: path,
size: size,
bw: bufio.NewWriterSize(&blockWriter{
client: d.client,
container: d.container,
path: path,
}, maxChunkSize),
}
}
func (w *writer) Write(p []byte) (int, error) {
if w.closed {
return 0, fmt.Errorf("already closed")
} else if w.committed {
return 0, fmt.Errorf("already committed")
} else if w.cancelled {
return 0, fmt.Errorf("already cancelled")
}
n, err := w.bw.Write(p)
w.size += int64(n)
return n, err
}
func (w *writer) Size() int64 {
return w.size
}
func (w *writer) Close() error {
if w.closed {
return fmt.Errorf("already closed")
}
w.closed = true
return w.bw.Flush()
}
func (w *writer) Cancel() error {
if w.closed {
return fmt.Errorf("already closed")
} else if w.committed {
return fmt.Errorf("already committed")
}
w.cancelled = true
return w.driver.client.DeleteBlob(w.driver.container, w.path, nil)
}
func (w *writer) Commit() error {
if w.closed {
return fmt.Errorf("already closed")
} else if w.committed {
return fmt.Errorf("already committed")
} else if w.cancelled {
return fmt.Errorf("already cancelled")
}
w.committed = true
return w.bw.Flush()
}
type blockWriter struct {
client azure.BlobStorageClient
container string
path string
}
func (bw *blockWriter) Write(p []byte) (int, error) {
n := 0
for offset := 0; offset < len(p); offset += maxChunkSize {
chunkSize := maxChunkSize
if offset+chunkSize > len(p) {
chunkSize = len(p) - offset
}
err := bw.client.AppendBlock(bw.container, bw.path, p[offset:offset+chunkSize], nil)
if err != nil {
return n, err
}
n += chunkSize
}
return n, nil
}