distribution/docs/storage/driver/s3/s3.go
Stephen J Day 0f897aea8f Attempt to address intermittent s3 RequestTimeout error
Signed-off-by: Stephen J Day <stephen.day@docker.com>
2015-04-23 20:07:32 -07:00

811 lines
21 KiB
Go

// Package s3 provides a storagedriver.StorageDriver implementation to
// store blobs in Amazon S3 cloud storage.
//
// This package leverages the AdRoll/goamz client library for interfacing with
// s3.
//
// Because s3 is a key, value store the Stat call does not support last modification
// time for directories (directories are an abstraction for key, value stores)
//
// Keep in mind that s3 guarantees only eventual consistency, so do not assume
// that a successful write will mean immediate access to the data written (although
// in most regions a new object put has guaranteed read after write). The only true
// guarantee is that once you call Stat and receive a certain file size, that much of
// the file is already accessible.
package s3
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"net/http"
"reflect"
"strconv"
"strings"
"sync"
"time"
"github.com/AdRoll/goamz/aws"
"github.com/AdRoll/goamz/s3"
"github.com/Sirupsen/logrus"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/base"
"github.com/docker/distribution/registry/storage/driver/factory"
)
const driverName = "s3"
// minChunkSize defines the minimum multipart upload chunk size
// S3 API requires multipart upload chunks to be at least 5MB
const minChunkSize = 5 << 20
const defaultChunkSize = 2 * minChunkSize
// listMax is the largest amount of objects you can request from S3 in a list call
const listMax = 1000
//DriverParameters A struct that encapsulates all of the driver parameters after all values have been set
type DriverParameters struct {
AccessKey string
SecretKey string
Bucket string
Region aws.Region
Encrypt bool
Secure bool
V4Auth bool
ChunkSize int64
RootDirectory string
}
func init() {
factory.Register(driverName, &s3DriverFactory{})
}
// s3DriverFactory implements the factory.StorageDriverFactory interface
type s3DriverFactory struct{}
func (factory *s3DriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return FromParameters(parameters)
}
type driver struct {
S3 *s3.S3
Bucket *s3.Bucket
ChunkSize int64
Encrypt bool
RootDirectory string
pool sync.Pool // pool []byte buffers used for WriteStream
zeros []byte // shared, zero-valued buffer used for WriteStream
}
type baseEmbed struct {
base.Base
}
// Driver is a storagedriver.StorageDriver implementation backed by Amazon S3
// Objects are stored at absolute keys in the provided bucket.
type Driver struct {
baseEmbed
}
// FromParameters constructs a new Driver with a given parameters map
// Required parameters:
// - accesskey
// - secretkey
// - region
// - bucket
// - encrypt
func FromParameters(parameters map[string]interface{}) (*Driver, error) {
// Providing no values for these is valid in case the user is authenticating
// with an IAM on an ec2 instance (in which case the instance credentials will
// be summoned when GetAuth is called)
accessKey, ok := parameters["accesskey"]
if !ok {
accessKey = ""
}
secretKey, ok := parameters["secretkey"]
if !ok {
secretKey = ""
}
regionName, ok := parameters["region"]
if !ok || fmt.Sprint(regionName) == "" {
return nil, fmt.Errorf("No region parameter provided")
}
region := aws.GetRegion(fmt.Sprint(regionName))
if region.Name == "" {
return nil, fmt.Errorf("Invalid region provided: %v", region)
}
bucket, ok := parameters["bucket"]
if !ok || fmt.Sprint(bucket) == "" {
return nil, fmt.Errorf("No bucket parameter provided")
}
encryptBool := false
encrypt, ok := parameters["encrypt"]
if ok {
encryptBool, ok = encrypt.(bool)
if !ok {
return nil, fmt.Errorf("The encrypt parameter should be a boolean")
}
}
secureBool := true
secure, ok := parameters["secure"]
if ok {
secureBool, ok = secure.(bool)
if !ok {
return nil, fmt.Errorf("The secure parameter should be a boolean")
}
}
v4AuthBool := false
v4Auth, ok := parameters["v4auth"]
if ok {
v4AuthBool, ok = v4Auth.(bool)
if !ok {
return nil, fmt.Errorf("The v4auth parameter should be a boolean")
}
}
chunkSize := int64(defaultChunkSize)
chunkSizeParam, ok := parameters["chunksize"]
if ok {
switch v := chunkSizeParam.(type) {
case string:
vv, err := strconv.ParseInt(v, 0, 64)
if err != nil {
return nil, fmt.Errorf("chunksize parameter must be an integer, %v invalid", chunkSizeParam)
}
chunkSize = vv
case int64:
chunkSize = v
case int, uint, int32, uint32, uint64:
chunkSize = reflect.ValueOf(v).Convert(reflect.TypeOf(chunkSize)).Int()
default:
return nil, fmt.Errorf("invalid valud for chunksize: %#v", chunkSizeParam)
}
if chunkSize <= minChunkSize {
return nil, fmt.Errorf("The chunksize %#v parameter should be a number that is larger than or equal to %d", chunkSize, minChunkSize)
}
}
rootDirectory, ok := parameters["rootdirectory"]
if !ok {
rootDirectory = ""
}
params := DriverParameters{
fmt.Sprint(accessKey),
fmt.Sprint(secretKey),
fmt.Sprint(bucket),
region,
encryptBool,
secureBool,
v4AuthBool,
chunkSize,
fmt.Sprint(rootDirectory),
}
return New(params)
}
// New constructs a new Driver with the given AWS credentials, region, encryption flag, and
// bucketName
func New(params DriverParameters) (*Driver, error) {
auth, err := aws.GetAuth(params.AccessKey, params.SecretKey, "", time.Time{})
if err != nil {
return nil, err
}
if !params.Secure {
params.Region.S3Endpoint = strings.Replace(params.Region.S3Endpoint, "https", "http", 1)
}
s3obj := s3.New(auth, params.Region)
bucket := s3obj.Bucket(params.Bucket)
if params.V4Auth {
s3obj.Signature = aws.V4Signature
} else {
if params.Region.Name == "eu-central-1" {
return nil, fmt.Errorf("The eu-central-1 region only works with v4 authentication")
}
}
// Validate that the given credentials have at least read permissions in the
// given bucket scope.
if _, err := bucket.List(strings.TrimRight(params.RootDirectory, "/"), "", "", 1); err != nil {
return nil, err
}
// TODO Currently multipart uploads have no timestamps, so this would be unwise
// if you initiated a new s3driver while another one is running on the same bucket.
// multis, _, err := bucket.ListMulti("", "")
// if err != nil {
// return nil, err
// }
// for _, multi := range multis {
// err := multi.Abort()
// //TODO appropriate to do this error checking?
// if err != nil {
// return nil, err
// }
// }
d := &driver{
S3: s3obj,
Bucket: bucket,
ChunkSize: params.ChunkSize,
Encrypt: params.Encrypt,
RootDirectory: params.RootDirectory,
zeros: make([]byte, params.ChunkSize),
}
d.pool.New = func() interface{} {
return make([]byte, d.ChunkSize)
}
return &Driver{
baseEmbed: baseEmbed{
Base: base.Base{
StorageDriver: d,
},
},
}, nil
}
// Implement the storagedriver.StorageDriver interface
// GetContent retrieves the content stored at "path" as a []byte.
func (d *driver) GetContent(path string) ([]byte, error) {
content, err := d.Bucket.Get(d.s3Path(path))
if err != nil {
return nil, parseError(path, err)
}
return content, nil
}
// PutContent stores the []byte content at a location designated by "path".
func (d *driver) PutContent(path string, contents []byte) error {
return parseError(path, d.Bucket.Put(d.s3Path(path), contents, d.getContentType(), getPermissions(), d.getOptions()))
}
// ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
// given byte offset.
func (d *driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
headers := make(http.Header)
headers.Add("Range", "bytes="+strconv.FormatInt(offset, 10)+"-")
resp, err := d.Bucket.GetResponseWithHeaders(d.s3Path(path), headers)
if err != nil {
if s3Err, ok := err.(*s3.Error); ok && s3Err.Code == "InvalidRange" {
return ioutil.NopCloser(bytes.NewReader(nil)), nil
}
return nil, parseError(path, err)
}
return resp.Body, nil
}
// WriteStream stores the contents of the provided io.Reader at a
// location designated by the given path. The driver will know it has
// received the full contents when the reader returns io.EOF. The number
// of successfully READ bytes will be returned, even if an error is
// returned. May be used to resume writing a stream by providing a nonzero
// offset. Offsets past the current size will write from the position
// beyond the end of the file.
func (d *driver) WriteStream(path string, offset int64, reader io.Reader) (totalRead int64, err error) {
partNumber := 1
bytesRead := 0
var putErrChan chan error
parts := []s3.Part{}
var part s3.Part
multi, err := d.Bucket.InitMulti(d.s3Path(path), d.getContentType(), getPermissions(), d.getOptions())
if err != nil {
return 0, err
}
buf := d.getbuf()
// We never want to leave a dangling multipart upload, our only consistent state is
// when there is a whole object at path. This is in order to remain consistent with
// the stat call.
//
// Note that if the machine dies before executing the defer, we will be left with a dangling
// multipart upload, which will eventually be cleaned up, but we will lose all of the progress
// made prior to the machine crashing.
defer func() {
if putErrChan != nil {
if putErr := <-putErrChan; putErr != nil {
err = putErr
}
}
if len(parts) > 0 {
if multi == nil {
// Parts should be empty if the multi is not initialized
panic("Unreachable")
} else {
if multi.Complete(parts) != nil {
multi.Abort()
}
}
}
d.putbuf(buf) // needs to be here to pick up new buf value
}()
// Fills from 0 to total from current
fromSmallCurrent := func(total int64) error {
current, err := d.ReadStream(path, 0)
if err != nil {
return err
}
bytesRead = 0
for int64(bytesRead) < total {
//The loop should very rarely enter a second iteration
nn, err := current.Read(buf[bytesRead:total])
bytesRead += nn
if err != nil {
if err != io.EOF {
return err
}
break
}
}
return nil
}
// Fills from parameter to chunkSize from reader
fromReader := func(from int64) error {
bytesRead = 0
for from+int64(bytesRead) < d.ChunkSize {
nn, err := reader.Read(buf[from+int64(bytesRead):])
totalRead += int64(nn)
bytesRead += nn
if err != nil {
if err != io.EOF {
return err
}
break
}
}
if putErrChan == nil {
putErrChan = make(chan error)
} else {
if putErr := <-putErrChan; putErr != nil {
putErrChan = nil
return putErr
}
}
go func(bytesRead int, from int64, buf []byte) {
defer d.putbuf(buf) // this buffer gets dropped after this call
// DRAGONS(stevvooe): There are few things one might want to know
// about this section. First, the putErrChan is expecting an error
// and a nil or just a nil to come through the channel. This is
// covered by the silly defer below. The other aspect is the s3
// retry backoff to deal with RequestTimeout errors. Even though
// the underlying s3 library should handle it, it doesn't seem to
// be part of the shouldRetry function (see AdRoll/goamz/s3).
defer func() {
putErrChan <- nil // for some reason, we do this no matter what.
}()
if bytesRead <= 0 {
return
}
var err error
var part s3.Part
loop:
for retries := 0; retries < 5; retries++ {
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf[0:int64(bytesRead)+from]))
if err == nil {
break // success!
}
// NOTE(stevvooe): This retry code tries to only retry under
// conditions where the s3 package does not. We may add s3
// error codes to the below if we see others bubble up in the
// application. Right now, the most troubling is
// RequestTimeout, which seems to only triggered when a tcp
// connection to s3 slows to a crawl. If the RequestTimeout
// ends up getting added to the s3 library and we don't see
// other errors, this retry loop can be removed.
switch err := err.(type) {
case *s3.Error:
switch err.Code {
case "RequestTimeout":
// allow retries on only this error.
default:
break loop
}
}
backoff := 100 * time.Millisecond * time.Duration(retries+1)
logrus.Errorf("error putting part, retrying after %v: %v", err, backoff.String())
time.Sleep(backoff)
}
if err != nil {
logrus.Errorf("error putting part, aborting: %v", err)
putErrChan <- err
}
// parts and partNumber are safe, because this function is the
// only one modifying them and we force it to be executed
// serially.
parts = append(parts, part)
partNumber++
}(bytesRead, from, buf)
buf = d.getbuf() // use a new buffer for the next call
return nil
}
if offset > 0 {
resp, err := d.Bucket.Head(d.s3Path(path), nil)
if err != nil {
if s3Err, ok := err.(*s3.Error); !ok || s3Err.Code != "NoSuchKey" {
return 0, err
}
}
currentLength := int64(0)
if err == nil {
currentLength = resp.ContentLength
}
if currentLength >= offset {
if offset < d.ChunkSize {
// chunkSize > currentLength >= offset
if err = fromSmallCurrent(offset); err != nil {
return totalRead, err
}
if err = fromReader(offset); err != nil {
return totalRead, err
}
if totalRead+offset < d.ChunkSize {
return totalRead, nil
}
} else {
// currentLength >= offset >= chunkSize
_, part, err = multi.PutPartCopy(partNumber,
s3.CopyOptions{CopySourceOptions: "bytes=0-" + strconv.FormatInt(offset-1, 10)},
d.Bucket.Name+"/"+d.s3Path(path))
if err != nil {
return 0, err
}
parts = append(parts, part)
partNumber++
}
} else {
// Fills between parameters with 0s but only when to - from <= chunkSize
fromZeroFillSmall := func(from, to int64) error {
bytesRead = 0
for from+int64(bytesRead) < to {
nn, err := bytes.NewReader(d.zeros).Read(buf[from+int64(bytesRead) : to])
bytesRead += nn
if err != nil {
return err
}
}
return nil
}
// Fills between parameters with 0s, making new parts
fromZeroFillLarge := func(from, to int64) error {
bytesRead64 := int64(0)
for to-(from+bytesRead64) >= d.ChunkSize {
part, err := multi.PutPart(int(partNumber), bytes.NewReader(d.zeros))
if err != nil {
return err
}
bytesRead64 += d.ChunkSize
parts = append(parts, part)
partNumber++
}
return fromZeroFillSmall(0, (to-from)%d.ChunkSize)
}
// currentLength < offset
if currentLength < d.ChunkSize {
if offset < d.ChunkSize {
// chunkSize > offset > currentLength
if err = fromSmallCurrent(currentLength); err != nil {
return totalRead, err
}
if err = fromZeroFillSmall(currentLength, offset); err != nil {
return totalRead, err
}
if err = fromReader(offset); err != nil {
return totalRead, err
}
if totalRead+offset < d.ChunkSize {
return totalRead, nil
}
} else {
// offset >= chunkSize > currentLength
if err = fromSmallCurrent(currentLength); err != nil {
return totalRead, err
}
if err = fromZeroFillSmall(currentLength, d.ChunkSize); err != nil {
return totalRead, err
}
part, err = multi.PutPart(int(partNumber), bytes.NewReader(buf))
if err != nil {
return totalRead, err
}
parts = append(parts, part)
partNumber++
//Zero fill from chunkSize up to offset, then some reader
if err = fromZeroFillLarge(d.ChunkSize, offset); err != nil {
return totalRead, err
}
if err = fromReader(offset % d.ChunkSize); err != nil {
return totalRead, err
}
if totalRead+(offset%d.ChunkSize) < d.ChunkSize {
return totalRead, nil
}
}
} else {
// offset > currentLength >= chunkSize
_, part, err = multi.PutPartCopy(partNumber,
s3.CopyOptions{},
d.Bucket.Name+"/"+d.s3Path(path))
if err != nil {
return 0, err
}
parts = append(parts, part)
partNumber++
//Zero fill from currentLength up to offset, then some reader
if err = fromZeroFillLarge(currentLength, offset); err != nil {
return totalRead, err
}
if err = fromReader((offset - currentLength) % d.ChunkSize); err != nil {
return totalRead, err
}
if totalRead+((offset-currentLength)%d.ChunkSize) < d.ChunkSize {
return totalRead, nil
}
}
}
}
for {
if err = fromReader(0); err != nil {
return totalRead, err
}
if int64(bytesRead) < d.ChunkSize {
break
}
}
return totalRead, nil
}
// Stat retrieves the FileInfo for the given path, including the current size
// in bytes and the creation time.
func (d *driver) Stat(path string) (storagedriver.FileInfo, error) {
listResponse, err := d.Bucket.List(d.s3Path(path), "", "", 1)
if err != nil {
return nil, err
}
fi := storagedriver.FileInfoFields{
Path: path,
}
if len(listResponse.Contents) == 1 {
if listResponse.Contents[0].Key != d.s3Path(path) {
fi.IsDir = true
} else {
fi.IsDir = false
fi.Size = listResponse.Contents[0].Size
timestamp, err := time.Parse(time.RFC3339Nano, listResponse.Contents[0].LastModified)
if err != nil {
return nil, err
}
fi.ModTime = timestamp
}
} else if len(listResponse.CommonPrefixes) == 1 {
fi.IsDir = true
} else {
return nil, storagedriver.PathNotFoundError{Path: path}
}
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
}
// List returns a list of the objects that are direct descendants of the given path.
func (d *driver) List(path string) ([]string, error) {
if path != "/" && path[len(path)-1] != '/' {
path = path + "/"
}
// This is to cover for the cases when the rootDirectory of the driver is either "" or "/".
// In those cases, there is no root prefix to replace and we must actually add a "/" to all
// results in order to keep them as valid paths as recognized by storagedriver.PathRegexp
prefix := ""
if d.s3Path("") == "" {
prefix = "/"
}
listResponse, err := d.Bucket.List(d.s3Path(path), "/", "", listMax)
if err != nil {
return nil, err
}
files := []string{}
directories := []string{}
for {
for _, key := range listResponse.Contents {
files = append(files, strings.Replace(key.Key, d.s3Path(""), prefix, 1))
}
for _, commonPrefix := range listResponse.CommonPrefixes {
directories = append(directories, strings.Replace(commonPrefix[0:len(commonPrefix)-1], d.s3Path(""), prefix, 1))
}
if listResponse.IsTruncated {
listResponse, err = d.Bucket.List(d.s3Path(path), "/", listResponse.NextMarker, listMax)
if err != nil {
return nil, err
}
} else {
break
}
}
return append(files, directories...), nil
}
// Move moves an object stored at sourcePath to destPath, removing the original
// object.
func (d *driver) Move(sourcePath string, destPath string) error {
/* This is terrible, but aws doesn't have an actual move. */
_, err := d.Bucket.PutCopy(d.s3Path(destPath), getPermissions(),
s3.CopyOptions{Options: d.getOptions(), ContentType: d.getContentType()}, d.Bucket.Name+"/"+d.s3Path(sourcePath))
if err != nil {
return parseError(sourcePath, err)
}
return d.Delete(sourcePath)
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(path string) error {
listResponse, err := d.Bucket.List(d.s3Path(path), "", "", listMax)
if err != nil || len(listResponse.Contents) == 0 {
return storagedriver.PathNotFoundError{Path: path}
}
s3Objects := make([]s3.Object, listMax)
for len(listResponse.Contents) > 0 {
for index, key := range listResponse.Contents {
s3Objects[index].Key = key.Key
}
err := d.Bucket.DelMulti(s3.Delete{Quiet: false, Objects: s3Objects[0:len(listResponse.Contents)]})
if err != nil {
return nil
}
listResponse, err = d.Bucket.List(d.s3Path(path), "", "", listMax)
if err != nil {
return err
}
}
return nil
}
// URLFor returns a URL which may be used to retrieve the content stored at the given path.
// May return an UnsupportedMethodErr in certain StorageDriver implementations.
func (d *driver) URLFor(path string, options map[string]interface{}) (string, error) {
methodString := "GET"
method, ok := options["method"]
if ok {
methodString, ok = method.(string)
if !ok || (methodString != "GET" && methodString != "HEAD") {
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
}
}
return d.Bucket.SignedURLWithMethod(methodString, d.s3Path(path), expiresTime, nil, nil), nil
}
func (d *driver) s3Path(path string) string {
return strings.TrimLeft(strings.TrimRight(d.RootDirectory, "/")+path, "/")
}
// S3BucketKey returns the s3 bucket key for the given storage driver path.
func (d *Driver) S3BucketKey(path string) string {
return d.StorageDriver.(*driver).s3Path(path)
}
func parseError(path string, err error) error {
if s3Err, ok := err.(*s3.Error); ok && s3Err.Code == "NoSuchKey" {
return storagedriver.PathNotFoundError{Path: path}
}
return err
}
func hasCode(err error, code string) bool {
s3err, ok := err.(*aws.Error)
return ok && s3err.Code == code
}
func (d *driver) getOptions() s3.Options {
return s3.Options{SSE: d.Encrypt}
}
func getPermissions() s3.ACL {
return s3.Private
}
func (d *driver) getContentType() string {
return "application/octet-stream"
}
// getbuf returns a buffer from the driver's pool with length d.ChunkSize.
func (d *driver) getbuf() []byte {
return d.pool.Get().([]byte)
}
func (d *driver) putbuf(p []byte) {
copy(p, d.zeros)
d.pool.Put(p)
}