minio/xl-v1-object.go
2016-05-28 15:15:53 -07:00

358 lines
10 KiB
Go

package main
import (
"crypto/md5"
"encoding/hex"
"io"
"path"
"path/filepath"
"strings"
"sync"
"time"
"github.com/minio/minio/pkg/mimedb"
)
/// Object Operations
// GetObject - get an object.
func (xl xlObjects) GetObject(bucket, object string, startOffset int64) (io.ReadCloser, error) {
// Verify if bucket is valid.
if !IsValidBucketName(bucket) {
return nil, BucketNameInvalid{Bucket: bucket}
}
// Verify if object is valid.
if !IsValidObjectName(object) {
return nil, ObjectNameInvalid{Bucket: bucket, Object: object}
}
nsMutex.RLock(bucket, object)
defer nsMutex.RUnlock(bucket, object)
fileReader, fileWriter := io.Pipe()
xlMeta, err := readXLMetadata(xl.getRandomDisk(), bucket, object)
if err != nil {
return nil, toObjectErr(err, bucket, object)
}
partIndex, offset, err := xlMeta.getPartNumberOffset(startOffset)
if err != nil {
return nil, toObjectErr(err, bucket, object)
}
// Hold a read lock once more which can be released after the following go-routine ends.
// We hold RLock once more because the current function would return before the go routine below
// executes and hence releasing the read lock (because of defer'ed nsMutex.RUnlock() call).
nsMutex.RLock(bucket, object)
go func() {
defer nsMutex.RUnlock(bucket, object)
for ; partIndex < len(xlMeta.Parts); partIndex++ {
part := xlMeta.Parts[partIndex]
r, err := xl.erasureDisk.ReadFile(bucket, pathJoin(object, part.Name), offset)
if err != nil {
fileWriter.CloseWithError(err)
return
}
// Reset offset to 0 as it would be non-0 only for the first loop if startOffset is non-0.
offset = 0
if _, err = io.Copy(fileWriter, r); err != nil {
switch reader := r.(type) {
case *io.PipeReader:
reader.CloseWithError(err)
case io.ReadCloser:
reader.Close()
}
fileWriter.CloseWithError(err)
return
}
// Close the readerCloser that reads multiparts of an object from the xl storage layer.
// Not closing leaks underlying file descriptors.
r.Close()
}
fileWriter.Close()
}()
return fileReader, nil
}
// GetObjectInfo - get object info.
func (xl xlObjects) GetObjectInfo(bucket, object string) (ObjectInfo, error) {
// Verify if bucket is valid.
if !IsValidBucketName(bucket) {
return ObjectInfo{}, BucketNameInvalid{Bucket: bucket}
}
// Verify if object is valid.
if !IsValidObjectName(object) {
return ObjectInfo{}, ObjectNameInvalid{Bucket: bucket, Object: object}
}
nsMutex.RLock(bucket, object)
defer nsMutex.RUnlock(bucket, object)
info, err := xl.getObjectInfo(bucket, object)
if err != nil {
return ObjectInfo{}, toObjectErr(err, bucket, object)
}
return info, nil
}
func (xl xlObjects) getObjectInfo(bucket, object string) (objInfo ObjectInfo, err error) {
// Count for errors encountered.
var xlJSONErrCount = 0
// Loop through and return the first success entry based on the
// selected random disk.
for xlJSONErrCount < len(xl.storageDisks) {
// Choose a random disk on each attempt, do not hit the same disk all the time.
disk := xl.getRandomDisk() // Pick a random disk.
var xlMeta xlMetaV1
xlMeta, err = readXLMetadata(disk, bucket, object)
if err == nil {
objInfo = ObjectInfo{}
objInfo.IsDir = false
objInfo.Bucket = bucket
objInfo.Name = object
objInfo.Size = xlMeta.Stat.Size
objInfo.ModTime = xlMeta.Stat.ModTime
objInfo.MD5Sum = xlMeta.Meta["md5Sum"]
objInfo.ContentType = xlMeta.Meta["content-type"]
objInfo.ContentEncoding = xlMeta.Meta["content-encoding"]
return objInfo, nil
}
xlJSONErrCount++ // Update error count.
}
// Return error at the end.
return ObjectInfo{}, err
}
// renameObject - renaming all source objects to destination object across all disks.
func (xl xlObjects) renameObject(srcBucket, srcObject, dstBucket, dstObject string) error {
// Initialize sync waitgroup.
var wg = &sync.WaitGroup{}
// Initialize list of errors.
var errs = make([]error, len(xl.storageDisks))
// Rename file on all underlying storage disks.
for index, disk := range xl.storageDisks {
// Append "/" as srcObject and dstObject are either leaf-dirs or non-leaf-dris.
// If srcObject is an object instead of prefix we just rename the leaf-dir and
// not rename the part and metadata files separately.
wg.Add(1)
go func(index int, disk StorageAPI) {
defer wg.Done()
err := disk.RenameFile(srcBucket, retainSlash(srcObject), dstBucket, retainSlash(dstObject))
if err != nil {
errs[index] = err
}
errs[index] = nil
}(index, disk)
}
// Wait for all RenameFile to finish.
wg.Wait()
// Gather err count.
var errCount = 0
for _, err := range errs {
if err == nil {
continue
}
errCount++
}
// We can safely allow RenameFile errors up to len(xl.storageDisks) - xl.writeQuorum
// otherwise return failure. Cleanup successful renames.
if errCount > len(xl.storageDisks)-xl.writeQuorum {
// Special condition if readQuorum exists, then return success.
if errCount <= len(xl.storageDisks)-xl.readQuorum {
return nil
}
xl.deleteObject(srcBucket, srcObject)
return errWriteQuorum
}
return nil
}
// PutObject - create an object.
func (xl xlObjects) PutObject(bucket string, object string, size int64, data io.Reader, metadata map[string]string) (string, error) {
// Verify if bucket is valid.
if !IsValidBucketName(bucket) {
return "", BucketNameInvalid{Bucket: bucket}
}
// Verify bucket exists.
if !xl.isBucketExist(bucket) {
return "", BucketNotFound{Bucket: bucket}
}
if !IsValidObjectName(object) {
return "", ObjectNameInvalid{
Bucket: bucket,
Object: object,
}
}
// No metadata is set, allocate a new one.
if metadata == nil {
metadata = make(map[string]string)
}
nsMutex.Lock(bucket, object)
defer nsMutex.Unlock(bucket, object)
tempErasureObj := path.Join(tmpMetaPrefix, bucket, object, "object1")
tempObj := path.Join(tmpMetaPrefix, bucket, object)
fileWriter, err := xl.erasureDisk.CreateFile(minioMetaBucket, tempErasureObj)
if err != nil {
return "", toObjectErr(err, bucket, object)
}
// Initialize md5 writer.
md5Writer := md5.New()
// Instantiate a new multi writer.
multiWriter := io.MultiWriter(md5Writer, fileWriter)
// Instantiate checksum hashers and create a multiwriter.
if size > 0 {
if _, err = io.CopyN(multiWriter, data, size); err != nil {
if clErr := safeCloseAndRemove(fileWriter); clErr != nil {
return "", toObjectErr(clErr, bucket, object)
}
return "", toObjectErr(err, bucket, object)
}
} else {
if _, err = io.Copy(multiWriter, data); err != nil {
if clErr := safeCloseAndRemove(fileWriter); clErr != nil {
return "", toObjectErr(clErr, bucket, object)
}
return "", toObjectErr(err, bucket, object)
}
}
// Save additional erasureMetadata.
modTime := time.Now().UTC()
newMD5Hex := hex.EncodeToString(md5Writer.Sum(nil))
// Update the md5sum if not set with the newly calculated one.
if len(metadata["md5Sum"]) == 0 {
metadata["md5Sum"] = newMD5Hex
}
// If not set default to "application/octet-stream"
if metadata["content-type"] == "" {
contentType := "application/octet-stream"
if objectExt := filepath.Ext(object); objectExt != "" {
content, ok := mimedb.DB[strings.ToLower(strings.TrimPrefix(objectExt, "."))]
if ok {
contentType = content.ContentType
}
}
metadata["content-type"] = contentType
}
// md5Hex representation.
md5Hex := metadata["md5Sum"]
if md5Hex != "" {
if newMD5Hex != md5Hex {
if err = safeCloseAndRemove(fileWriter); err != nil {
return "", toObjectErr(err, bucket, object)
}
return "", BadDigest{md5Hex, newMD5Hex}
}
}
err = fileWriter.Close()
if err != nil {
if clErr := safeCloseAndRemove(fileWriter); clErr != nil {
return "", toObjectErr(clErr, bucket, object)
}
return "", toObjectErr(err, bucket, object)
}
// Check if an object is present as one of the parent dir.
if xl.parentDirIsObject(bucket, path.Dir(object)) {
return "", toObjectErr(errFileAccessDenied, bucket, object)
}
// Delete if an object already exists.
err = xl.deleteObject(bucket, object)
if err != nil {
return "", toObjectErr(err, bucket, object)
}
err = xl.renameObject(minioMetaBucket, tempObj, bucket, object)
if err != nil {
if dErr := xl.deleteObject(minioMetaBucket, tempObj); dErr != nil {
return "", toObjectErr(dErr, minioMetaBucket, tempObj)
}
return "", toObjectErr(err, bucket, object)
}
xlMeta := xlMetaV1{}
xlMeta.Version = "1"
xlMeta.Format = "xl"
xlMeta.Meta = metadata
xlMeta.Stat.Size = size
xlMeta.Stat.ModTime = modTime
xlMeta.AddObjectPart("object1", newMD5Hex, xlMeta.Stat.Size)
if err = xl.writeXLMetadata(bucket, object, xlMeta); err != nil {
return "", toObjectErr(err, bucket, object)
}
// Return md5sum, successfully wrote object.
return newMD5Hex, nil
}
// deleteObject - deletes a regular object.
func (xl xlObjects) deleteObject(bucket, object string) error {
// Initialize sync waitgroup.
var wg = &sync.WaitGroup{}
// Initialize list of errors.
var dErrs = make([]error, len(xl.storageDisks))
for index, disk := range xl.storageDisks {
wg.Add(1)
go func(index int, disk StorageAPI) {
defer wg.Done()
dErrs[index] = cleanupDir(disk, bucket, object)
}(index, disk)
}
// Wait for all routines to finish.
wg.Wait()
var fileNotFoundCnt, deleteFileErr int
// Loop through all the concocted errors.
for _, err := range dErrs {
if err == nil {
continue
}
// If file not found, count them.
if err == errFileNotFound {
fileNotFoundCnt++
continue
}
// Update error counter separately.
deleteFileErr++
}
// Return err if all disks report file not found.
if fileNotFoundCnt == len(xl.storageDisks) {
return errFileNotFound
} else if deleteFileErr > len(xl.storageDisks)-xl.writeQuorum {
// Return errWriteQuorum if errors were more than
// allowed write quorum.
return errWriteQuorum
}
return nil
}
// DeleteObject - delete the object.
func (xl xlObjects) DeleteObject(bucket, object string) error {
// Verify if bucket is valid.
if !IsValidBucketName(bucket) {
return BucketNameInvalid{Bucket: bucket}
}
if !IsValidObjectName(object) {
return ObjectNameInvalid{Bucket: bucket, Object: object}
}
nsMutex.Lock(bucket, object)
defer nsMutex.Unlock(bucket, object)
xl.deleteObject(bucket, object)
return nil
}