distribution/registry/storage/driver/swift/swift.go
Stefan Majewsky 4c9bed2507 don't swallow errors in Swift driver's GetContent()
In 326c3a9c49, which was only intended to
be a refactoring commit, the behavior of this block subtly changed so
that unknown types of errors would be swallowed instead of propagated.

I noticed this while investigating an error similar to #1539 aka
docker/docker#21290. It appears that during GetContent() for a
hashstate, the Swift proxy produces an error. Since this error was
silently swallowed, an empty []byte is used to restart the hash, then
producing the digest of the empty string instead of the layer's digest.

This PR will not fix the issue, but it should make the actual error more
visible by propagating it into `blobWriter#resumeDigest' and
'blobWriter#validateBlob', respectively.

Signed-off-by: Stefan Majewsky <stefan.majewsky@sap.com>
2016-03-30 16:11:29 +02:00

782 lines
21 KiB
Go

// Package swift provides a storagedriver.StorageDriver implementation to
// store blobs in Openstack Swift object storage.
//
// This package leverages the ncw/swift client library for interfacing with
// Swift.
//
// It supports both TempAuth authentication and Keystone authentication
// (up to version 3).
//
// As Swift has a limit on the size of a single uploaded object (by default
// this is 5GB), the driver makes use of the Swift Large Object Support
// (http://docs.openstack.org/developer/swift/overview_large_objects.html).
// Only one container is used for both manifests and data objects. Manifests
// are stored in the 'files' pseudo directory, data objects are stored under
// 'segments'.
package swift
import (
"bufio"
"bytes"
"crypto/rand"
"crypto/sha1"
"crypto/tls"
"encoding/hex"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"strconv"
"strings"
"time"
"github.com/mitchellh/mapstructure"
"github.com/ncw/swift"
"github.com/docker/distribution/context"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/base"
"github.com/docker/distribution/registry/storage/driver/factory"
"github.com/docker/distribution/version"
)
const driverName = "swift"
// defaultChunkSize defines the default size of a segment
const defaultChunkSize = 20 * 1024 * 1024
// minChunkSize defines the minimum size of a segment
const minChunkSize = 1 << 20
// contentType defines the Content-Type header associated with stored segments
const contentType = "application/octet-stream"
// readAfterWriteTimeout defines the time we wait before an object appears after having been uploaded
var readAfterWriteTimeout = 15 * time.Second
// readAfterWriteWait defines the time to sleep between two retries
var readAfterWriteWait = 200 * time.Millisecond
// Parameters A struct that encapsulates all of the driver parameters after all values have been set
type Parameters struct {
Username string
Password string
AuthURL string
Tenant string
TenantID string
Domain string
DomainID string
TrustID string
Region string
Container string
Prefix string
InsecureSkipVerify bool
ChunkSize int
SecretKey string
AccessKey string
TempURLContainerKey bool
TempURLMethods []string
}
// swiftInfo maps the JSON structure returned by Swift /info endpoint
type swiftInfo struct {
Swift struct {
Version string `mapstructure:"version"`
}
Tempurl struct {
Methods []string `mapstructure:"methods"`
}
}
func init() {
factory.Register(driverName, &swiftDriverFactory{})
}
// swiftDriverFactory implements the factory.StorageDriverFactory interface
type swiftDriverFactory struct{}
func (factory *swiftDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return FromParameters(parameters)
}
type driver struct {
Conn swift.Connection
Container string
Prefix string
BulkDeleteSupport bool
ChunkSize int
SecretKey string
AccessKey string
TempURLContainerKey bool
TempURLMethods []string
}
type baseEmbed struct {
base.Base
}
// Driver is a storagedriver.StorageDriver implementation backed by Openstack Swift
// Objects are stored at absolute keys in the provided container.
type Driver struct {
baseEmbed
}
// FromParameters constructs a new Driver with a given parameters map
// Required parameters:
// - username
// - password
// - authurl
// - container
func FromParameters(parameters map[string]interface{}) (*Driver, error) {
params := Parameters{
ChunkSize: defaultChunkSize,
InsecureSkipVerify: false,
}
if err := mapstructure.Decode(parameters, &params); err != nil {
return nil, err
}
if params.Username == "" {
return nil, fmt.Errorf("No username parameter provided")
}
if params.Password == "" {
return nil, fmt.Errorf("No password parameter provided")
}
if params.AuthURL == "" {
return nil, fmt.Errorf("No authurl parameter provided")
}
if params.Container == "" {
return nil, fmt.Errorf("No container parameter provided")
}
if params.ChunkSize < minChunkSize {
return nil, fmt.Errorf("The chunksize %#v parameter should be a number that is larger than or equal to %d", params.ChunkSize, minChunkSize)
}
return New(params)
}
// New constructs a new Driver with the given Openstack Swift credentials and container name
func New(params Parameters) (*Driver, error) {
transport := &http.Transport{
Proxy: http.ProxyFromEnvironment,
MaxIdleConnsPerHost: 2048,
TLSClientConfig: &tls.Config{InsecureSkipVerify: params.InsecureSkipVerify},
}
ct := swift.Connection{
UserName: params.Username,
ApiKey: params.Password,
AuthUrl: params.AuthURL,
Region: params.Region,
UserAgent: "distribution/" + version.Version,
Tenant: params.Tenant,
TenantId: params.TenantID,
Domain: params.Domain,
DomainId: params.DomainID,
TrustId: params.TrustID,
Transport: transport,
ConnectTimeout: 60 * time.Second,
Timeout: 15 * 60 * time.Second,
}
err := ct.Authenticate()
if err != nil {
return nil, fmt.Errorf("Swift authentication failed: %s", err)
}
if _, _, err := ct.Container(params.Container); err == swift.ContainerNotFound {
if err := ct.ContainerCreate(params.Container, nil); err != nil {
return nil, fmt.Errorf("Failed to create container %s (%s)", params.Container, err)
}
} else if err != nil {
return nil, fmt.Errorf("Failed to retrieve info about container %s (%s)", params.Container, err)
}
d := &driver{
Conn: ct,
Container: params.Container,
Prefix: params.Prefix,
ChunkSize: params.ChunkSize,
TempURLMethods: make([]string, 0),
AccessKey: params.AccessKey,
}
info := swiftInfo{}
if config, err := d.Conn.QueryInfo(); err == nil {
_, d.BulkDeleteSupport = config["bulk_delete"]
if err := mapstructure.Decode(config, &info); err == nil {
d.TempURLContainerKey = info.Swift.Version >= "2.3.0"
d.TempURLMethods = info.Tempurl.Methods
}
} else {
d.TempURLContainerKey = params.TempURLContainerKey
d.TempURLMethods = params.TempURLMethods
}
if len(d.TempURLMethods) > 0 {
secretKey := params.SecretKey
if secretKey == "" {
secretKey, _ = generateSecret()
}
// Since Swift 2.2.2, we can now set secret keys on containers
// in addition to the account secret keys. Use them in preference.
if d.TempURLContainerKey {
_, containerHeaders, err := d.Conn.Container(d.Container)
if err != nil {
return nil, fmt.Errorf("Failed to fetch container info %s (%s)", d.Container, err)
}
d.SecretKey = containerHeaders["X-Container-Meta-Temp-Url-Key"]
if d.SecretKey == "" || (params.SecretKey != "" && d.SecretKey != params.SecretKey) {
m := swift.Metadata{}
m["temp-url-key"] = secretKey
if d.Conn.ContainerUpdate(d.Container, m.ContainerHeaders()); err == nil {
d.SecretKey = secretKey
}
}
} else {
// Use the account secret key
_, accountHeaders, err := d.Conn.Account()
if err != nil {
return nil, fmt.Errorf("Failed to fetch account info (%s)", err)
}
d.SecretKey = accountHeaders["X-Account-Meta-Temp-Url-Key"]
if d.SecretKey == "" || (params.SecretKey != "" && d.SecretKey != params.SecretKey) {
m := swift.Metadata{}
m["temp-url-key"] = secretKey
if err := d.Conn.AccountUpdate(m.AccountHeaders()); err == nil {
d.SecretKey = secretKey
}
}
}
}
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) {
content, err := d.Conn.ObjectGetBytes(d.Container, d.swiftPath(path))
if err == swift.ObjectNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return content, err
}
// PutContent stores the []byte content at a location designated by "path".
func (d *driver) PutContent(ctx context.Context, path string, contents []byte) error {
err := d.Conn.ObjectPutBytes(d.Container, d.swiftPath(path), contents, contentType)
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
// 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) {
headers := make(swift.Headers)
headers["Range"] = "bytes=" + strconv.FormatInt(offset, 10) + "-"
file, _, err := d.Conn.ObjectOpen(d.Container, d.swiftPath(path), false, headers)
if err == swift.ObjectNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
}
if swiftErr, ok := err.(*swift.Error); ok && swiftErr.StatusCode == http.StatusRequestedRangeNotSatisfiable {
return ioutil.NopCloser(bytes.NewReader(nil)), nil
}
return file, err
}
// 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) {
var (
segments []swift.Object
segmentsPath string
err error
)
if !append {
segmentsPath, err = d.swiftSegmentPath(path)
if err != nil {
return nil, err
}
} else {
info, headers, err := d.Conn.Object(d.Container, d.swiftPath(path))
if err == swift.ObjectNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
} else if err != nil {
return nil, err
}
manifest, ok := headers["X-Object-Manifest"]
if !ok {
segmentsPath, err = d.swiftSegmentPath(path)
if err != nil {
return nil, err
}
if err := d.Conn.ObjectMove(d.Container, d.swiftPath(path), d.Container, segmentPath(segmentsPath, len(segments))); err != nil {
return nil, err
}
segments = []swift.Object{info}
} else {
_, segmentsPath = parseManifest(manifest)
if segments, err = d.getAllSegments(segmentsPath); err != nil {
return nil, err
}
}
}
return d.newWriter(path, segmentsPath, segments), 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) {
swiftPath := d.swiftPath(path)
opts := &swift.ObjectsOpts{
Prefix: swiftPath,
Delimiter: '/',
}
objects, err := d.Conn.ObjectsAll(d.Container, opts)
if err != nil {
if err == swift.ContainerNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return nil, err
}
fi := storagedriver.FileInfoFields{
Path: strings.TrimPrefix(strings.TrimSuffix(swiftPath, "/"), d.swiftPath("/")),
}
for _, obj := range objects {
if obj.PseudoDirectory && obj.Name == swiftPath+"/" {
fi.IsDir = true
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
} else if obj.Name == swiftPath {
// On Swift 1.12, the 'bytes' field is always 0
// so we need to do a second HEAD request
info, _, err := d.Conn.Object(d.Container, swiftPath)
if err != nil {
if err == swift.ObjectNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return nil, err
}
fi.IsDir = false
fi.Size = info.Bytes
fi.ModTime = info.LastModified
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
}
}
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) {
var files []string
prefix := d.swiftPath(path)
if prefix != "" {
prefix += "/"
}
opts := &swift.ObjectsOpts{
Prefix: prefix,
Delimiter: '/',
}
objects, err := d.Conn.ObjectsAll(d.Container, opts)
for _, obj := range objects {
files = append(files, strings.TrimPrefix(strings.TrimSuffix(obj.Name, "/"), d.swiftPath("/")))
}
if err == swift.ContainerNotFound || (len(objects) == 0 && path != "/") {
return files, storagedriver.PathNotFoundError{Path: path}
}
return files, err
}
// 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 {
_, headers, err := d.Conn.Object(d.Container, d.swiftPath(sourcePath))
if err == nil {
if manifest, ok := headers["X-Object-Manifest"]; ok {
if err = d.createManifest(destPath, manifest); err != nil {
return err
}
err = d.Conn.ObjectDelete(d.Container, d.swiftPath(sourcePath))
} else {
err = d.Conn.ObjectMove(d.Container, d.swiftPath(sourcePath), d.Container, d.swiftPath(destPath))
}
}
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: sourcePath}
}
return err
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(ctx context.Context, path string) error {
opts := swift.ObjectsOpts{
Prefix: d.swiftPath(path) + "/",
}
objects, err := d.Conn.ObjectsAll(d.Container, &opts)
if err != nil {
if err == swift.ContainerNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
for _, obj := range objects {
if obj.PseudoDirectory {
continue
}
if _, headers, err := d.Conn.Object(d.Container, obj.Name); err == nil {
manifest, ok := headers["X-Object-Manifest"]
if ok {
_, prefix := parseManifest(manifest)
segments, err := d.getAllSegments(prefix)
if err != nil {
return err
}
objects = append(objects, segments...)
}
} else {
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: obj.Name}
}
return err
}
}
if d.BulkDeleteSupport && len(objects) > 0 {
filenames := make([]string, len(objects))
for i, obj := range objects {
filenames[i] = obj.Name
}
_, err = d.Conn.BulkDelete(d.Container, filenames)
// Don't fail on ObjectNotFound because eventual consistency
// makes this situation normal.
if err != nil && err != swift.Forbidden && err != swift.ObjectNotFound {
if err == swift.ContainerNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
} else {
for _, obj := range objects {
if err := d.Conn.ObjectDelete(d.Container, obj.Name); err != nil {
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: obj.Name}
}
return err
}
}
}
_, _, err = d.Conn.Object(d.Container, d.swiftPath(path))
if err == nil {
if err := d.Conn.ObjectDelete(d.Container, d.swiftPath(path)); err != nil {
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
} else if err == swift.ObjectNotFound {
if len(objects) == 0 {
return storagedriver.PathNotFoundError{Path: path}
}
} else {
return err
}
return nil
}
// URLFor returns a URL which may be used to retrieve the content stored at the given path.
func (d *driver) URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) {
if d.SecretKey == "" {
return "", storagedriver.ErrUnsupportedMethod{}
}
methodString := "GET"
method, ok := options["method"]
if ok {
if methodString, ok = method.(string); !ok {
return "", storagedriver.ErrUnsupportedMethod{}
}
}
if methodString == "HEAD" {
// A "HEAD" request on a temporary URL is allowed if the
// signature was generated with "GET", "POST" or "PUT"
methodString = "GET"
}
supported := false
for _, method := range d.TempURLMethods {
if method == methodString {
supported = true
break
}
}
if !supported {
return "", storagedriver.ErrUnsupportedMethod{}
}
expiresTime := time.Now().Add(20 * time.Minute)
expires, ok := options["expiry"]
if ok {
et, ok := expires.(time.Time)
if ok {
expiresTime = et
}
}
tempURL := d.Conn.ObjectTempUrl(d.Container, d.swiftPath(path), d.SecretKey, methodString, expiresTime)
if d.AccessKey != "" {
// On HP Cloud, the signature must be in the form of tenant_id:access_key:signature
url, _ := url.Parse(tempURL)
query := url.Query()
query.Set("temp_url_sig", fmt.Sprintf("%s:%s:%s", d.Conn.TenantId, d.AccessKey, query.Get("temp_url_sig")))
url.RawQuery = query.Encode()
tempURL = url.String()
}
return tempURL, nil
}
func (d *driver) swiftPath(path string) string {
return strings.TrimLeft(strings.TrimRight(d.Prefix+"/files"+path, "/"), "/")
}
func (d *driver) swiftSegmentPath(path string) (string, error) {
checksum := sha1.New()
random := make([]byte, 32)
if _, err := rand.Read(random); err != nil {
return "", err
}
path = hex.EncodeToString(checksum.Sum(append([]byte(path), random...)))
return strings.TrimLeft(strings.TrimRight(d.Prefix+"/segments/"+path[0:3]+"/"+path[3:], "/"), "/"), nil
}
func (d *driver) getAllSegments(path string) ([]swift.Object, error) {
segments, err := d.Conn.ObjectsAll(d.Container, &swift.ObjectsOpts{Prefix: path})
if err == swift.ContainerNotFound {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return segments, err
}
func (d *driver) createManifest(path string, segments string) error {
headers := make(swift.Headers)
headers["X-Object-Manifest"] = segments
manifest, err := d.Conn.ObjectCreate(d.Container, d.swiftPath(path), false, "", contentType, headers)
if err != nil {
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
if err := manifest.Close(); err != nil {
if err == swift.ObjectNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
return nil
}
func parseManifest(manifest string) (container string, prefix string) {
components := strings.SplitN(manifest, "/", 2)
container = components[0]
if len(components) > 1 {
prefix = components[1]
}
return container, prefix
}
func generateSecret() (string, error) {
var secretBytes [32]byte
if _, err := rand.Read(secretBytes[:]); err != nil {
return "", fmt.Errorf("could not generate random bytes for Swift secret key: %v", err)
}
return hex.EncodeToString(secretBytes[:]), nil
}
func segmentPath(segmentsPath string, partNumber int) string {
return fmt.Sprintf("%s/%016d", segmentsPath, partNumber)
}
type writer struct {
driver *driver
path string
segmentsPath string
size int64
bw *bufio.Writer
closed bool
committed bool
cancelled bool
}
func (d *driver) newWriter(path, segmentsPath string, segments []swift.Object) storagedriver.FileWriter {
var size int64
for _, segment := range segments {
size += segment.Bytes
}
return &writer{
driver: d,
path: path,
segmentsPath: segmentsPath,
size: size,
bw: bufio.NewWriterSize(&segmentWriter{
conn: d.Conn,
container: d.Container,
segmentsPath: segmentsPath,
segmentNumber: len(segments) + 1,
maxChunkSize: d.ChunkSize,
}, d.ChunkSize),
}
}
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")
}
if err := w.bw.Flush(); err != nil {
return err
}
if !w.committed && !w.cancelled {
if err := w.driver.createManifest(w.path, w.driver.Container+"/"+w.segmentsPath); err != nil {
return err
}
}
w.closed = true
return nil
}
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.Delete(context.Background(), w.path)
}
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")
}
if err := w.bw.Flush(); err != nil {
return err
}
if err := w.driver.createManifest(w.path, w.driver.Container+"/"+w.segmentsPath); err != nil {
return err
}
w.committed = true
var err error
waitingTime := readAfterWriteWait
endTime := time.Now().Add(readAfterWriteTimeout)
for {
var info swift.Object
if info, _, err = w.driver.Conn.Object(w.driver.Container, w.driver.swiftPath(w.path)); err == nil {
if info.Bytes == w.size {
break
}
err = fmt.Errorf("Timeout expired while waiting for segments of %s to show up", w.path)
}
if time.Now().Add(waitingTime).After(endTime) {
break
}
time.Sleep(waitingTime)
waitingTime *= 2
}
return err
}
type segmentWriter struct {
conn swift.Connection
container string
segmentsPath string
segmentNumber int
maxChunkSize int
}
func (sw *segmentWriter) Write(p []byte) (int, error) {
n := 0
for offset := 0; offset < len(p); offset += sw.maxChunkSize {
chunkSize := sw.maxChunkSize
if offset+chunkSize > len(p) {
chunkSize = len(p) - offset
}
_, err := sw.conn.ObjectPut(sw.container, segmentPath(sw.segmentsPath, sw.segmentNumber), bytes.NewReader(p[offset:offset+chunkSize]), false, "", contentType, nil)
if err != nil {
return n, err
}
sw.segmentNumber++
n += chunkSize
}
return n, nil
}