Add everything back into one project hood, still missing iodine

pkg/storage/donut/.gitignore

@@ -0,0 +1,2 @@
+donut
+build-constants.go

pkg/storage/donut/LICENSE

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
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+
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+   See the License for the specific language governing permissions and
+   limitations under the License.

pkg/storage/donut/README.md

@@ -0,0 +1,3 @@
+# Donut
+
+donut - Donut (do not delete) on disk format implementation released under [Apache license v2](./LICENSE).

pkg/storage/donut/donut.go

@@ -0,0 +1,87 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+
+	"github.com/minio-io/iodine"
+)
+
+// donut struct internal data
+type donut struct {
+	name    string
+	buckets map[string]Bucket
+	nodes   map[string]Node
+}
+
+// config files used inside Donut
+const (
+	donutObjectMetadataConfig = "donutObjectMetadata.json"
+	objectMetadataConfig      = "objectMetadata.json"
+	donutConfig               = "donutMetadata.json"
+)
+
+// attachDonutNode - wrapper function to instantiate a new node for associated donut
+// based on the provided configuration
+func (d donut) attachDonutNode(hostname string, disks []string) error {
+	node, err := NewNode(hostname)
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	for i, disk := range disks {
+		// Order is necessary for maps, keep order number separately
+		newDisk, err := NewDisk(disk, i)
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		if err := newDisk.MakeDir(d.name); err != nil {
+			return iodine.New(err, nil)
+		}
+		if err := node.AttachDisk(newDisk); err != nil {
+			return iodine.New(err, nil)
+		}
+	}
+	if err := d.AttachNode(node); err != nil {
+		return iodine.New(err, nil)
+	}
+	return nil
+}
+
+// NewDonut - instantiate a new donut
+func NewDonut(donutName string, nodeDiskMap map[string][]string) (Donut, error) {
+	if donutName == "" || len(nodeDiskMap) == 0 {
+		return nil, iodine.New(errors.New("invalid argument"), nil)
+	}
+	nodes := make(map[string]Node)
+	buckets := make(map[string]Bucket)
+	d := donut{
+		name:    donutName,
+		nodes:   nodes,
+		buckets: buckets,
+	}
+	for k, v := range nodeDiskMap {
+		if len(v) == 0 {
+			return nil, iodine.New(errors.New("invalid number of disks per node"), nil)
+		}
+		err := d.attachDonutNode(k, v)
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+	}
+	return d, nil
+}

pkg/storage/donut/donut_bucket.go

@@ -0,0 +1,209 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+	"time"
+
+	"crypto/md5"
+	"encoding/hex"
+
+	"github.com/minio-io/iodine"
+)
+
+// internal struct carrying bucket specific information
+type bucket struct {
+	name      string
+	donutName string
+	nodes     map[string]Node
+	objects   map[string]Object
+}
+
+// NewBucket - instantiate a new bucket
+func NewBucket(bucketName, donutName string, nodes map[string]Node) (Bucket, error) {
+	errParams := map[string]string{
+		"bucketName": bucketName,
+		"donutName":  donutName,
+	}
+	if strings.TrimSpace(bucketName) == "" || strings.TrimSpace(donutName) == "" {
+		return nil, iodine.New(errors.New("invalid argument"), errParams)
+	}
+	b := bucket{}
+	b.name = bucketName
+	b.donutName = donutName
+	b.objects = make(map[string]Object)
+	b.nodes = nodes
+	return b, nil
+}
+
+// ListObjects - list all objects
+func (b bucket) ListObjects() (map[string]Object, error) {
+	nodeSlice := 0
+	for _, node := range b.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+		for _, disk := range disks {
+			bucketSlice := fmt.Sprintf("%s$%d$%d", b.name, nodeSlice, disk.GetOrder())
+			bucketPath := path.Join(b.donutName, bucketSlice)
+			objects, err := disk.ListDir(bucketPath)
+			if err != nil {
+				return nil, iodine.New(err, nil)
+			}
+			for _, object := range objects {
+				newObject, err := NewObject(object.Name(), path.Join(disk.GetPath(), bucketPath))
+				if err != nil {
+					return nil, iodine.New(err, nil)
+				}
+				newObjectMetadata, err := newObject.GetObjectMetadata()
+				if err != nil {
+					return nil, iodine.New(err, nil)
+				}
+				objectName, ok := newObjectMetadata["object"]
+				if !ok {
+					return nil, iodine.New(errors.New("object corrupted"), nil)
+				}
+				b.objects[objectName] = newObject
+			}
+		}
+		nodeSlice = nodeSlice + 1
+	}
+	return b.objects, nil
+}
+
+// GetObject - get object
+func (b bucket) GetObject(objectName string) (reader io.ReadCloser, size int64, err error) {
+	reader, writer := io.Pipe()
+	// get list of objects
+	objects, err := b.ListObjects()
+	if err != nil {
+		return nil, 0, iodine.New(err, nil)
+	}
+	// check if object exists
+	object, ok := objects[objectName]
+	if !ok {
+		return nil, 0, iodine.New(os.ErrNotExist, nil)
+	}
+	// verify if objectMetadata is readable, before we serve the request
+	objectMetadata, err := object.GetObjectMetadata()
+	if err != nil {
+		return nil, 0, iodine.New(err, nil)
+	}
+	if objectName == "" || writer == nil || len(objectMetadata) == 0 {
+		return nil, 0, iodine.New(errors.New("invalid argument"), nil)
+	}
+	size, err = strconv.ParseInt(objectMetadata["size"], 10, 64)
+	if err != nil {
+		return nil, 0, iodine.New(err, nil)
+	}
+	// verify if donutObjectMetadata is readable, before we server the request
+	donutObjectMetadata, err := object.GetDonutObjectMetadata()
+	if err != nil {
+		return nil, 0, iodine.New(err, nil)
+	}
+	// read and reply back to GetObject() request in a go-routine
+	go b.readEncodedData(b.normalizeObjectName(objectName), writer, donutObjectMetadata)
+	return reader, size, nil
+}
+
+// PutObject - put a new object
+func (b bucket) PutObject(objectName string, objectData io.Reader, expectedMD5Sum string, metadata map[string]string) error {
+	if objectName == "" || objectData == nil {
+		return iodine.New(errors.New("invalid argument"), nil)
+	}
+	writers, err := b.getDiskWriters(b.normalizeObjectName(objectName), "data")
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	summer := md5.New()
+	objectMetadata := make(map[string]string)
+	donutObjectMetadata := make(map[string]string)
+	objectMetadata["version"] = "1.0"
+	donutObjectMetadata["version"] = "1.0"
+	// if total writers are only '1' do not compute erasure
+	switch len(writers) == 1 {
+	case true:
+		mw := io.MultiWriter(writers[0], summer)
+		totalLength, err := io.Copy(mw, objectData)
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		donutObjectMetadata["sys.size"] = strconv.FormatInt(totalLength, 10)
+		objectMetadata["size"] = strconv.FormatInt(totalLength, 10)
+	case false:
+		// calculate data and parity dictated by total number of writers
+		k, m, err := b.getDataAndParity(len(writers))
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		// encoded data with k, m and write
+		chunkCount, totalLength, err := b.writeEncodedData(k, m, writers, objectData, summer)
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		/// donutMetadata section
+		donutObjectMetadata["sys.blockSize"] = strconv.Itoa(10 * 1024 * 1024)
+		donutObjectMetadata["sys.chunkCount"] = strconv.Itoa(chunkCount)
+		donutObjectMetadata["sys.erasureK"] = strconv.FormatUint(uint64(k), 10)
+		donutObjectMetadata["sys.erasureM"] = strconv.FormatUint(uint64(m), 10)
+		donutObjectMetadata["sys.erasureTechnique"] = "Cauchy"
+		donutObjectMetadata["sys.size"] = strconv.Itoa(totalLength)
+		// keep size inside objectMetadata as well for Object API requests
+		objectMetadata["size"] = strconv.Itoa(totalLength)
+	}
+	objectMetadata["bucket"] = b.name
+	objectMetadata["object"] = objectName
+	// store all user provided metadata
+	for k, v := range metadata {
+		objectMetadata[k] = v
+	}
+	dataMd5sum := summer.Sum(nil)
+	objectMetadata["created"] = time.Now().Format(time.RFC3339Nano)
+
+	// keeping md5sum for the object in two different places
+	// one for object storage and another is for internal use
+	objectMetadata["md5"] = hex.EncodeToString(dataMd5sum)
+	donutObjectMetadata["sys.md5"] = hex.EncodeToString(dataMd5sum)
+
+	// Verify if the written object is equal to what is expected, only if it is requested as such
+	if strings.TrimSpace(expectedMD5Sum) != "" {
+		if err := b.isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), objectMetadata["md5"]); err != nil {
+			return iodine.New(err, nil)
+		}
+	}
+	// write donut specific metadata
+	if err := b.writeDonutObjectMetadata(b.normalizeObjectName(objectName), donutObjectMetadata); err != nil {
+		return iodine.New(err, nil)
+	}
+	// write object specific metadata
+	if err := b.writeObjectMetadata(b.normalizeObjectName(objectName), objectMetadata); err != nil {
+		return iodine.New(err, nil)
+	}
+	// close all writers, when control flow reaches here
+	for _, writer := range writers {
+		writer.Close()
+	}
+	return nil
+}

pkg/storage/donut/donut_bucket_internal.go

@@ -0,0 +1,315 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"hash"
+	"io"
+	"path"
+	"strconv"
+	"strings"
+
+	"github.com/minio-io/iodine"
+	"github.com/minio-io/minio/pkg/utils/split"
+)
+
+/// This file contains all the internal functions used by Bucket interface
+
+// isMD5SumEqual - returns error if md5sum mismatches, other its `nil`
+func (b bucket) isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) error {
+	if strings.TrimSpace(expectedMD5Sum) != "" && strings.TrimSpace(actualMD5Sum) != "" {
+		expectedMD5SumBytes, err := hex.DecodeString(expectedMD5Sum)
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		actualMD5SumBytes, err := hex.DecodeString(actualMD5Sum)
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		if !bytes.Equal(expectedMD5SumBytes, actualMD5SumBytes) {
+			return iodine.New(errors.New("bad digest, md5sum mismatch"), nil)
+		}
+		return nil
+	}
+	return iodine.New(errors.New("invalid argument"), nil)
+}
+
+// writeObjectMetadata - write additional object metadata
+func (b bucket) writeObjectMetadata(objectName string, objectMetadata map[string]string) error {
+	if len(objectMetadata) == 0 {
+		return iodine.New(errors.New("invalid argument"), nil)
+	}
+	objectMetadataWriters, err := b.getDiskWriters(objectName, objectMetadataConfig)
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	for _, objectMetadataWriter := range objectMetadataWriters {
+		defer objectMetadataWriter.Close()
+	}
+	for _, objectMetadataWriter := range objectMetadataWriters {
+		jenc := json.NewEncoder(objectMetadataWriter)
+		if err := jenc.Encode(objectMetadata); err != nil {
+			return iodine.New(err, nil)
+		}
+	}
+	return nil
+}
+
+// writeDonutObjectMetadata - write donut related object metadata
+func (b bucket) writeDonutObjectMetadata(objectName string, objectMetadata map[string]string) error {
+	if len(objectMetadata) == 0 {
+		return iodine.New(errors.New("invalid argument"), nil)
+	}
+	objectMetadataWriters, err := b.getDiskWriters(objectName, donutObjectMetadataConfig)
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	for _, objectMetadataWriter := range objectMetadataWriters {
+		defer objectMetadataWriter.Close()
+	}
+	for _, objectMetadataWriter := range objectMetadataWriters {
+		jenc := json.NewEncoder(objectMetadataWriter)
+		if err := jenc.Encode(objectMetadata); err != nil {
+			return iodine.New(err, nil)
+		}
+	}
+	return nil
+}
+
+// TODO - This a temporary normalization of objectNames, need to find a better way
+//
+// normalizedObjectName - all objectNames with "/" get normalized to a simple objectName
+//
+// example:
+// user provided value - "this/is/my/deep/directory/structure"
+// donut normalized value - "this-is-my-deep-directory-structure"
+//
+func (b bucket) normalizeObjectName(objectName string) string {
+	// replace every '/' with '-'
+	return strings.Replace(objectName, "/", "-", -1)
+}
+
+// getDataAndParity - calculate k, m (data and parity) values from number of disks
+func (b bucket) getDataAndParity(totalWriters int) (k uint8, m uint8, err error) {
+	if totalWriters <= 1 {
+		return 0, 0, iodine.New(errors.New("invalid argument"), nil)
+	}
+	quotient := totalWriters / 2 // not using float or abs to let integer round off to lower value
+	// quotient cannot be bigger than (255 / 2) = 127
+	if quotient > 127 {
+		return 0, 0, iodine.New(errors.New("parity over flow"), nil)
+	}
+	remainder := totalWriters % 2 // will be 1 for odd and 0 for even numbers
+	k = uint8(quotient + remainder)
+	m = uint8(quotient)
+	return k, m, nil
+}
+
+// writeEncodedData -
+func (b bucket) writeEncodedData(k, m uint8, writers []io.WriteCloser, objectData io.Reader, summer hash.Hash) (int, int, error) {
+	chunks := split.Stream(objectData, 10*1024*1024)
+	encoder, err := NewEncoder(k, m, "Cauchy")
+	if err != nil {
+		return 0, 0, iodine.New(err, nil)
+	}
+	chunkCount := 0
+	totalLength := 0
+	for chunk := range chunks {
+		if chunk.Err == nil {
+			totalLength = totalLength + len(chunk.Data)
+			encodedBlocks, _ := encoder.Encode(chunk.Data)
+			summer.Write(chunk.Data)
+			for blockIndex, block := range encodedBlocks {
+				_, err := io.Copy(writers[blockIndex], bytes.NewBuffer(block))
+				if err != nil {
+					return 0, 0, iodine.New(err, nil)
+				}
+			}
+		}
+		chunkCount = chunkCount + 1
+	}
+	return chunkCount, totalLength, nil
+}
+
+// readEncodedData -
+func (b bucket) readEncodedData(objectName string, writer *io.PipeWriter, donutObjectMetadata map[string]string) {
+	expectedMd5sum, err := hex.DecodeString(donutObjectMetadata["sys.md5"])
+	if err != nil {
+		writer.CloseWithError(iodine.New(err, nil))
+		return
+	}
+	readers, err := b.getDiskReaders(objectName, "data")
+	if err != nil {
+		writer.CloseWithError(iodine.New(err, nil))
+		return
+	}
+	hasher := md5.New()
+	mwriter := io.MultiWriter(writer, hasher)
+	switch len(readers) == 1 {
+	case false:
+		totalChunks, totalLeft, blockSize, k, m, err := b.donutMetadata2Values(donutObjectMetadata)
+		if err != nil {
+			writer.CloseWithError(iodine.New(err, nil))
+			return
+		}
+		technique, ok := donutObjectMetadata["sys.erasureTechnique"]
+		if !ok {
+			err := errors.New("missing erasure Technique")
+			writer.CloseWithError(iodine.New(err, nil))
+			return
+		}
+		encoder, err := NewEncoder(uint8(k), uint8(m), technique)
+		if err != nil {
+			writer.CloseWithError(iodine.New(err, nil))
+			return
+		}
+		for i := 0; i < totalChunks; i++ {
+			decodedData, err := b.decodeEncodedData(totalLeft, blockSize, readers, encoder, writer)
+			if err != nil {
+				writer.CloseWithError(iodine.New(err, nil))
+				return
+			}
+			_, err = io.Copy(mwriter, bytes.NewBuffer(decodedData))
+			if err != nil {
+				writer.CloseWithError(iodine.New(err, nil))
+				return
+			}
+			totalLeft = totalLeft - int64(blockSize)
+		}
+	case true:
+		_, err := io.Copy(writer, readers[0])
+		if err != nil {
+			writer.CloseWithError(iodine.New(err, nil))
+			return
+		}
+	}
+	// check if decodedData md5sum matches
+	if !bytes.Equal(expectedMd5sum, hasher.Sum(nil)) {
+		err := errors.New("checksum mismatch")
+		writer.CloseWithError(iodine.New(err, nil))
+		return
+	}
+	writer.Close()
+	return
+}
+
+// decodeEncodedData -
+func (b bucket) decodeEncodedData(totalLeft, blockSize int64, readers []io.ReadCloser, encoder Encoder, writer *io.PipeWriter) ([]byte, error) {
+	var curBlockSize int64
+	if blockSize < totalLeft {
+		curBlockSize = blockSize
+	} else {
+		curBlockSize = totalLeft // cast is safe, blockSize in if protects
+	}
+	curChunkSize, err := encoder.GetEncodedBlockLen(int(curBlockSize))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	encodedBytes := make([][]byte, len(readers))
+	for i, reader := range readers {
+		var bytesBuffer bytes.Buffer
+		_, err := io.CopyN(&bytesBuffer, reader, int64(curChunkSize))
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+		encodedBytes[i] = bytesBuffer.Bytes()
+	}
+	decodedData, err := encoder.Decode(encodedBytes, int(curBlockSize))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return decodedData, nil
+}
+
+// donutMetadata2Values -
+func (b bucket) donutMetadata2Values(donutObjectMetadata map[string]string) (totalChunks int, totalLeft, blockSize int64, k, m uint64, err error) {
+	totalChunks, err = strconv.Atoi(donutObjectMetadata["sys.chunkCount"])
+	if err != nil {
+		return 0, 0, 0, 0, 0, iodine.New(err, nil)
+	}
+	totalLeft, err = strconv.ParseInt(donutObjectMetadata["sys.size"], 10, 64)
+	if err != nil {
+		return 0, 0, 0, 0, 0, iodine.New(err, nil)
+	}
+	blockSize, err = strconv.ParseInt(donutObjectMetadata["sys.blockSize"], 10, 64)
+	if err != nil {
+		return 0, 0, 0, 0, 0, iodine.New(err, nil)
+	}
+	k, err = strconv.ParseUint(donutObjectMetadata["sys.erasureK"], 10, 8)
+	if err != nil {
+		return 0, 0, 0, 0, 0, iodine.New(err, nil)
+	}
+	m, err = strconv.ParseUint(donutObjectMetadata["sys.erasureM"], 10, 8)
+	if err != nil {
+		return 0, 0, 0, 0, 0, iodine.New(err, nil)
+	}
+	return totalChunks, totalLeft, blockSize, k, m, nil
+}
+
+// getDiskReaders -
+func (b bucket) getDiskReaders(objectName, objectMeta string) ([]io.ReadCloser, error) {
+	var readers []io.ReadCloser
+	nodeSlice := 0
+	for _, node := range b.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+		readers = make([]io.ReadCloser, len(disks))
+		for _, disk := range disks {
+			bucketSlice := fmt.Sprintf("%s$%d$%d", b.name, nodeSlice, disk.GetOrder())
+			objectPath := path.Join(b.donutName, bucketSlice, objectName, objectMeta)
+			objectSlice, err := disk.OpenFile(objectPath)
+			if err != nil {
+				return nil, iodine.New(err, nil)
+			}
+			readers[disk.GetOrder()] = objectSlice
+		}
+		nodeSlice = nodeSlice + 1
+	}
+	return readers, nil
+}
+
+// getDiskWriters -
+func (b bucket) getDiskWriters(objectName, objectMeta string) ([]io.WriteCloser, error) {
+	var writers []io.WriteCloser
+	nodeSlice := 0
+	for _, node := range b.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+		writers = make([]io.WriteCloser, len(disks))
+		for _, disk := range disks {
+			bucketSlice := fmt.Sprintf("%s$%d$%d", b.name, nodeSlice, disk.GetOrder())
+			objectPath := path.Join(b.donutName, bucketSlice, objectName, objectMeta)
+			objectSlice, err := disk.MakeFile(objectPath)
+			if err != nil {
+				return nil, iodine.New(err, nil)
+			}
+			writers[disk.GetOrder()] = objectSlice
+		}
+		nodeSlice = nodeSlice + 1
+	}
+	return writers, nil
+}

pkg/storage/donut/donut_common.go

@@ -0,0 +1,75 @@
+package donut
+
+import (
+	"sort"
+	"strings"
+)
+
+func appendUniq(slice []string, i string) []string {
+	for _, ele := range slice {
+		if ele == i {
+			return slice
+		}
+	}
+	return append(slice, i)
+}
+
+func filterPrefix(objects []string, prefix string) []string {
+	var results []string
+	for _, object := range objects {
+		if strings.HasPrefix(object, prefix) {
+			results = append(results, object)
+		}
+	}
+	return results
+}
+
+func removePrefix(objects []string, prefix string) []string {
+	var results []string
+	for _, object := range objects {
+		results = append(results, strings.TrimPrefix(object, prefix))
+	}
+	return results
+}
+
+func filterDelimited(objects []string, delim string) []string {
+	var results []string
+	for _, object := range objects {
+		if !strings.Contains(object, delim) {
+			results = append(results, object)
+		}
+	}
+	return results
+}
+
+func filterNotDelimited(objects []string, delim string) []string {
+	var results []string
+	for _, object := range objects {
+		if strings.Contains(object, delim) {
+			results = append(results, object)
+		}
+	}
+	return results
+}
+
+func extractDir(objects []string, delim string) []string {
+	var results []string
+	for _, object := range objects {
+		parts := strings.Split(object, delim)
+		results = append(results, parts[0]+delim)
+	}
+	return results
+}
+
+func uniqueObjects(objects []string) []string {
+	objectMap := make(map[string]string)
+	for _, v := range objects {
+		objectMap[v] = v
+	}
+	var results []string
+	for k := range objectMap {
+		results = append(results, k)
+	}
+	sort.Strings(results)
+	return results
+}

pkg/storage/donut/donut_disk.go

@@ -0,0 +1,153 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"os"
+	"path"
+	"syscall"
+
+	"io/ioutil"
+
+	"github.com/minio-io/iodine"
+)
+
+// internal disk struct
+type disk struct {
+	root       string
+	order      int
+	filesystem map[string]string
+}
+
+// NewDisk - instantiate new disk
+func NewDisk(diskPath string, diskOrder int) (Disk, error) {
+	if diskPath == "" || diskOrder < 0 {
+		return nil, iodine.New(errors.New("invalid argument"), nil)
+	}
+	s := syscall.Statfs_t{}
+	err := syscall.Statfs(diskPath, &s)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	st, err := os.Stat(diskPath)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	if !st.IsDir() {
+		return nil, iodine.New(syscall.ENOTDIR, nil)
+	}
+	d := disk{
+		root:       diskPath,
+		order:      diskOrder,
+		filesystem: make(map[string]string),
+	}
+	if fsType := d.getFSType(s.Type); fsType != "UNKNOWN" {
+		d.filesystem["FSType"] = fsType
+		d.filesystem["MountPoint"] = d.root
+		return d, nil
+	}
+	return nil, iodine.New(errors.New("unsupported filesystem"), nil)
+}
+
+// GetPath - get root disk path
+func (d disk) GetPath() string {
+	return d.root
+}
+
+// GetOrder - get order of disk present in graph
+func (d disk) GetOrder() int {
+	return d.order
+}
+
+// GetFSInfo - get disk filesystem and its usage information
+func (d disk) GetFSInfo() map[string]string {
+	s := syscall.Statfs_t{}
+	err := syscall.Statfs(d.root, &s)
+	if err != nil {
+		return nil
+	}
+	d.filesystem["Total"] = d.formatBytes(s.Bsize * int64(s.Blocks))
+	d.filesystem["Free"] = d.formatBytes(s.Bsize * int64(s.Bfree))
+	return d.filesystem
+}
+
+// MakeDir - make a directory inside disk root path
+func (d disk) MakeDir(dirname string) error {
+	return os.MkdirAll(path.Join(d.root, dirname), 0700)
+}
+
+// ListDir - list a directory inside disk root path, get only directories
+func (d disk) ListDir(dirname string) ([]os.FileInfo, error) {
+	contents, err := ioutil.ReadDir(path.Join(d.root, dirname))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	var directories []os.FileInfo
+	for _, content := range contents {
+		// Include only directories, ignore everything else
+		if content.IsDir() {
+			directories = append(directories, content)
+		}
+	}
+	return directories, nil
+}
+
+// ListFiles - list a directory inside disk root path, get only files
+func (d disk) ListFiles(dirname string) ([]os.FileInfo, error) {
+	contents, err := ioutil.ReadDir(path.Join(d.root, dirname))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	var files []os.FileInfo
+	for _, content := range contents {
+		// Include only regular files, ignore everything else
+		if content.Mode().IsRegular() {
+			files = append(files, content)
+		}
+	}
+	return files, nil
+}
+
+// MakeFile - create a file inside disk root path
+func (d disk) MakeFile(filename string) (*os.File, error) {
+	if filename == "" {
+		return nil, iodine.New(errors.New("Invalid argument"), nil)
+	}
+	filePath := path.Join(d.root, filename)
+	// Create directories if they don't exist
+	if err := os.MkdirAll(path.Dir(filePath), 0700); err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	dataFile, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0600)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return dataFile, nil
+}
+
+// OpenFile - read a file inside disk root path
+func (d disk) OpenFile(filename string) (*os.File, error) {
+	if filename == "" {
+		return nil, iodine.New(errors.New("Invalid argument"), nil)
+	}
+	dataFile, err := os.Open(path.Join(d.root, filename))
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return dataFile, nil
+}

pkg/storage/donut/donut_disk_internal.go

@@ -0,0 +1,67 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+/// This file contains all the internal functions used inside Disk interface
+
+// formatBytes - Convert bytes to human readable string. Like a 2 MB, 64.2 KB, 52 B
+func (d disk) formatBytes(i int64) (result string) {
+	switch {
+	case i > (1024 * 1024 * 1024 * 1024):
+		result = fmt.Sprintf("%.02f TB", float64(i)/1024/1024/1024/1024)
+	case i > (1024 * 1024 * 1024):
+		result = fmt.Sprintf("%.02f GB", float64(i)/1024/1024/1024)
+	case i > (1024 * 1024):
+		result = fmt.Sprintf("%.02f MB", float64(i)/1024/1024)
+	case i > 1024:
+		result = fmt.Sprintf("%.02f KB", float64(i)/1024)
+	default:
+		result = fmt.Sprintf("%d B", i)
+	}
+	result = strings.Trim(result, " ")
+	return
+}
+
+// fsType2StrinMap - list of filesystems supported by donut
+var fsType2StringMap = map[string]string{
+	"137d":     "EXT",
+	"ef51":     "EXT2OLD",
+	"ef53":     "EXT4",
+	"4244":     "HFS",
+	"5346544e": "NTFS",
+	"4d44":     "MSDOS",
+	"52654973": "REISERFS",
+	"6969":     "NFS",
+	"01021994": "TMPFS",
+	"58465342": "XFS",
+}
+
+// getFSType - get filesystem type
+func (d disk) getFSType(fsType int64) string {
+	fsTypeHex := strconv.FormatInt(fsType, 16)
+	fsTypeString, ok := fsType2StringMap[fsTypeHex]
+	if ok == false {
+		return "UNKNOWN"
+	}
+	return fsTypeString
+}

pkg/storage/donut/donut_encoder.go

@@ -0,0 +1,97 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"strconv"
+
+	"github.com/minio-io/iodine"
+	encoding "github.com/minio-io/minio/pkg/erasure"
+)
+
+// encoder internal struct
+type encoder struct {
+	encoder   *encoding.Erasure
+	k, m      uint8
+	technique encoding.Technique
+}
+
+// getErasureTechnique - convert technique string into Technique type
+func getErasureTechnique(technique string) (encoding.Technique, error) {
+	switch true {
+	case technique == "Cauchy":
+		return encoding.Cauchy, nil
+	case technique == "Vandermonde":
+		return encoding.Cauchy, nil
+	default:
+		return encoding.None, iodine.New(errors.New("Invalid erasure technique"), nil)
+	}
+}
+
+// NewEncoder - instantiate a new encoder
+func NewEncoder(k, m uint8, technique string) (Encoder, error) {
+	errParams := map[string]string{
+		"k":         strconv.FormatUint(uint64(k), 10),
+		"m":         strconv.FormatUint(uint64(m), 10),
+		"technique": technique,
+	}
+	e := encoder{}
+	t, err := getErasureTechnique(technique)
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	params, err := encoding.ValidateParams(k, m, t)
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	e.encoder = encoding.NewErasure(params)
+	e.k = k
+	e.m = m
+	e.technique = t
+	return e, nil
+}
+
+// TODO - think again if this is needed
+// GetEncodedBlockLen - wrapper around erasure function with the same name
+func (e encoder) GetEncodedBlockLen(dataLength int) (int, error) {
+	if dataLength <= 0 {
+		return 0, iodine.New(errors.New("invalid argument"), nil)
+	}
+	return encoding.GetEncodedBlockLen(dataLength, e.k), nil
+}
+
+// Encode - erasure code input bytes
+func (e encoder) Encode(data []byte) (encodedData [][]byte, err error) {
+	if data == nil {
+		return nil, iodine.New(errors.New("invalid argument"), nil)
+	}
+	encodedData, err = e.encoder.Encode(data)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return encodedData, nil
+}
+
+// Decode - erasure decode input encoded bytes
+func (e encoder) Decode(encodedData [][]byte, dataLength int) (data []byte, err error) {
+	decodedData, err := e.encoder.Decode(encodedData, dataLength)
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	return decodedData, nil
+}

pkg/storage/donut/donut_internal_interfaces.go

@@ -0,0 +1,69 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"io"
+	"os"
+)
+
+// Encoder interface
+type Encoder interface {
+	GetEncodedBlockLen(dataLength int) (int, error)
+	Encode(data []byte) (encodedData [][]byte, err error)
+	Decode(encodedData [][]byte, dataLength int) (data []byte, err error)
+}
+
+// Bucket interface
+type Bucket interface {
+	ListObjects() (map[string]Object, error)
+
+	GetObject(object string) (io.ReadCloser, int64, error)
+	PutObject(object string, contents io.Reader, expectedMD5Sum string, metadata map[string]string) error
+}
+
+// Object interface
+type Object interface {
+	GetObjectMetadata() (map[string]string, error)
+	GetDonutObjectMetadata() (map[string]string, error)
+}
+
+// Node interface
+type Node interface {
+	ListDisks() (map[string]Disk, error)
+	AttachDisk(disk Disk) error
+	DetachDisk(disk Disk) error
+
+	GetNodeName() string
+	SaveConfig() error
+	LoadConfig() error
+}
+
+// Disk interface
+type Disk interface {
+	MakeDir(dirname string) error
+
+	ListDir(dirname string) ([]os.FileInfo, error)
+	ListFiles(dirname string) ([]os.FileInfo, error)
+
+	MakeFile(path string) (*os.File, error)
+	OpenFile(path string) (*os.File, error)
+
+	GetPath() string
+	GetOrder() int
+	GetFSInfo() map[string]string
+}

pkg/storage/donut/donut_node.go

@@ -0,0 +1,77 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+
+	"github.com/minio-io/iodine"
+)
+
+// node struct internal
+type node struct {
+	hostname string
+	disks    map[string]Disk
+}
+
+// NewNode - instantiates a new node
+func NewNode(hostname string) (Node, error) {
+	if hostname == "" {
+		return nil, iodine.New(errors.New("invalid argument"), nil)
+	}
+	disks := make(map[string]Disk)
+	n := node{
+		hostname: hostname,
+		disks:    disks,
+	}
+	return n, nil
+}
+
+// GetNodeName - return hostname
+func (n node) GetNodeName() string {
+	return n.hostname
+}
+
+// ListDisks - return number of disks
+func (n node) ListDisks() (map[string]Disk, error) {
+	return n.disks, nil
+}
+
+// AttachDisk - attach a disk
+func (n node) AttachDisk(disk Disk) error {
+	if disk == nil {
+		return iodine.New(errors.New("Invalid argument"), nil)
+	}
+	n.disks[disk.GetPath()] = disk
+	return nil
+}
+
+// DetachDisk - detach a disk
+func (n node) DetachDisk(disk Disk) error {
+	delete(n.disks, disk.GetPath())
+	return nil
+}
+
+// SaveConfig - save node configuration
+func (n node) SaveConfig() error {
+	return errors.New("Not Implemented")
+}
+
+// LoadConfig - load node configuration from saved configs
+func (n node) LoadConfig() error {
+	return errors.New("Not Implemented")
+}

pkg/storage/donut/donut_object.go

@@ -0,0 +1,70 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"path"
+
+	"encoding/json"
+	"io/ioutil"
+)
+
+// object internal struct
+type object struct {
+	name                string
+	objectPath          string
+	objectMetadata      map[string]string
+	donutObjectMetadata map[string]string
+}
+
+// NewObject - instantiate a new object
+func NewObject(objectName, p string) (Object, error) {
+	if objectName == "" {
+		return nil, errors.New("invalid argument")
+	}
+	o := object{}
+	o.name = objectName
+	o.objectPath = path.Join(p, objectName)
+	return o, nil
+}
+
+func (o object) GetObjectMetadata() (map[string]string, error) {
+	objectMetadata := make(map[string]string)
+	objectMetadataBytes, err := ioutil.ReadFile(path.Join(o.objectPath, objectMetadataConfig))
+	if err != nil {
+		return nil, err
+	}
+	if err := json.Unmarshal(objectMetadataBytes, &objectMetadata); err != nil {
+		return nil, err
+	}
+	o.objectMetadata = objectMetadata
+	return o.objectMetadata, nil
+}
+
+func (o object) GetDonutObjectMetadata() (map[string]string, error) {
+	donutObjectMetadata := make(map[string]string)
+	donutObjectMetadataBytes, err := ioutil.ReadFile(path.Join(o.objectPath, donutObjectMetadataConfig))
+	if err != nil {
+		return nil, err
+	}
+	if err := json.Unmarshal(donutObjectMetadataBytes, &donutObjectMetadata); err != nil {
+		return nil, err
+	}
+	o.donutObjectMetadata = donutObjectMetadata
+	return o.donutObjectMetadata, nil
+}

pkg/storage/donut/donut_public_interfaces.go

@@ -0,0 +1,57 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import "io"
+
+// Collection of Donut specification interfaces
+
+// Donut is a collection of object storage and management interface
+type Donut interface {
+	ObjectStorage
+	Management
+}
+
+// ObjectStorage is a donut object storage interface
+type ObjectStorage interface {
+	// Storage service Operations
+	GetBucketMetadata(bucket string) (map[string]string, error)
+	SetBucketMetadata(bucket string, metadata map[string]string) error
+	ListBuckets() ([]string, error)
+	MakeBucket(bucket string) error
+
+	// Bucket Operations
+	ListObjects(bucket, prefix, marker, delim string, maxKeys int) (result []string, prefixes []string, isTruncated bool, err error)
+
+	// Object Operations
+	GetObject(bucket, object string) (io.ReadCloser, int64, error)
+	GetObjectMetadata(bucket, object string) (map[string]string, error)
+	PutObject(bucket, object, expectedMD5Sum string, reader io.ReadCloser, metadata map[string]string) error
+}
+
+// Management is a donut management system interface
+type Management interface {
+	Heal() error
+	Rebalance() error
+	Info() (map[string][]string, error)
+
+	AttachNode(node Node) error
+	DetachNode(node Node) error
+
+	SaveConfig() error
+	LoadConfig() error
+}

pkg/storage/donut/donut_rebalance.go

@@ -0,0 +1,56 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/minio-io/iodine"
+)
+
+// Rebalance -
+func (d donut) Rebalance() error {
+	var totalOffSetLength int
+	var newDisks []Disk
+	var existingDirs []os.FileInfo
+	for _, node := range d.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		totalOffSetLength = len(disks)
+		fmt.Println(totalOffSetLength)
+		for _, disk := range disks {
+			dirs, err := disk.ListDir(d.name)
+			if err != nil {
+				return iodine.New(err, nil)
+			}
+			if len(dirs) == 0 {
+				newDisks = append(newDisks, disk)
+			}
+			existingDirs = append(existingDirs, dirs...)
+		}
+	}
+	for _, dir := range existingDirs {
+		splits := strings.Split(dir.Name(), "$")
+		bucketName, segment, offset := splits[0], splits[1], splits[2]
+		fmt.Println(bucketName, segment, offset)
+	}
+	return nil
+}

pkg/storage/donut/donut_test.go

@@ -0,0 +1,333 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/hex"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"strconv"
+	"testing"
+	"time"
+
+	. "github.com/minio-io/check"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type MySuite struct{}
+
+var _ = Suite(&MySuite{})
+
+// create a dummy TestNodeDiskMap
+func createTestNodeDiskMap(p string) map[string][]string {
+	nodes := make(map[string][]string)
+	nodes["localhost"] = make([]string, 16)
+	for i := 0; i < len(nodes["localhost"]); i++ {
+		diskPath := path.Join(p, strconv.Itoa(i))
+		if _, err := os.Stat(diskPath); err != nil {
+			if os.IsNotExist(err) {
+				os.MkdirAll(diskPath, 0700)
+			}
+		}
+		nodes["localhost"][i] = diskPath
+	}
+	return nodes
+}
+
+// test empty donut
+func (s *MySuite) TestEmptyDonut(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	// check donut is empty
+	buckets, err := donut.ListBuckets()
+	c.Assert(err, IsNil)
+	c.Assert(buckets, IsNil)
+}
+
+// test make bucket without name
+func (s *MySuite) TestBucketWithoutNameFails(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+	// fail to create new bucket without a name
+	err = donut.MakeBucket("")
+	c.Assert(err, Not(IsNil))
+
+	err = donut.MakeBucket(" ")
+	c.Assert(err, Not(IsNil))
+}
+
+// test empty bucket
+func (s *MySuite) TestEmptyBucket(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	c.Assert(donut.MakeBucket("foo"), IsNil)
+	// check if bucket is empty
+	objects, _, istruncated, err := donut.ListObjects("foo", "", "", "", 1)
+	c.Assert(err, IsNil)
+	c.Assert(objects, IsNil)
+	c.Assert(istruncated, Equals, false)
+}
+
+// test bucket list
+func (s *MySuite) TestMakeBucketAndList(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+	// create bucket
+	err = donut.MakeBucket("foo")
+	c.Assert(err, IsNil)
+
+	// check bucket exists
+	buckets, err := donut.ListBuckets()
+	c.Assert(err, IsNil)
+	c.Assert(buckets, DeepEquals, []string{"foo"})
+}
+
+// test re-create bucket
+func (s *MySuite) TestMakeBucketWithSameNameFails(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+	err = donut.MakeBucket("foo")
+	c.Assert(err, IsNil)
+
+	err = donut.MakeBucket("foo")
+	c.Assert(err, Not(IsNil))
+}
+
+// test make multiple buckets
+func (s *MySuite) TestCreateMultipleBucketsAndList(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+	// add a second bucket
+	err = donut.MakeBucket("foo")
+	c.Assert(err, IsNil)
+
+	err = donut.MakeBucket("bar")
+	c.Assert(err, IsNil)
+
+	buckets, err := donut.ListBuckets()
+	c.Assert(err, IsNil)
+	c.Assert(buckets, DeepEquals, []string{"bar", "foo"})
+
+	err = donut.MakeBucket("foobar")
+	c.Assert(err, IsNil)
+
+	buckets, err = donut.ListBuckets()
+	c.Assert(err, IsNil)
+	c.Assert(buckets, DeepEquals, []string{"bar", "foo", "foobar"})
+}
+
+// test object create without bucket
+func (s *MySuite) TestNewObjectFailsWithoutBucket(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+	err = donut.PutObject("foo", "obj", "", nil, nil)
+	c.Assert(err, Not(IsNil))
+}
+
+// test create object metadata
+func (s *MySuite) TestNewObjectMetadata(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	metadata := make(map[string]string)
+	metadata["contentType"] = "application/json"
+	metadata["foo"] = "value1"
+	metadata["hello"] = "world"
+
+	data := "Hello World"
+	hasher := md5.New()
+	hasher.Write([]byte(data))
+	expectedMd5Sum := hex.EncodeToString(hasher.Sum(nil))
+	reader := ioutil.NopCloser(bytes.NewReader([]byte(data)))
+
+	err = donut.MakeBucket("foo")
+	c.Assert(err, IsNil)
+
+	err = donut.PutObject("foo", "obj", expectedMd5Sum, reader, metadata)
+	c.Assert(err, IsNil)
+
+	objectMetadata, err := donut.GetObjectMetadata("foo", "obj")
+	c.Assert(err, IsNil)
+
+	c.Assert(objectMetadata["contentType"], Equals, metadata["contentType"])
+	c.Assert(objectMetadata["foo"], Equals, metadata["foo"])
+	c.Assert(objectMetadata["hello"], Equals, metadata["hello"])
+}
+
+// test create object fails without name
+func (s *MySuite) TestNewObjectFailsWithEmptyName(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	err = donut.PutObject("foo", "", "", nil, nil)
+	c.Assert(err, Not(IsNil))
+
+	err = donut.PutObject("foo", " ", "", nil, nil)
+	c.Assert(err, Not(IsNil))
+}
+
+// test create object
+func (s *MySuite) TestNewObjectCanBeWritten(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	err = donut.MakeBucket("foo")
+	c.Assert(err, IsNil)
+
+	metadata := make(map[string]string)
+	metadata["contentType"] = "application/octet-stream"
+	data := "Hello World"
+
+	hasher := md5.New()
+	hasher.Write([]byte(data))
+	expectedMd5Sum := hex.EncodeToString(hasher.Sum(nil))
+	reader := ioutil.NopCloser(bytes.NewReader([]byte(data)))
+
+	err = donut.PutObject("foo", "obj", expectedMd5Sum, reader, metadata)
+	c.Assert(err, IsNil)
+
+	reader, size, err := donut.GetObject("foo", "obj")
+	c.Assert(err, IsNil)
+	c.Assert(size, Equals, int64(len(data)))
+
+	var actualData bytes.Buffer
+	_, err = io.Copy(&actualData, reader)
+	c.Assert(err, IsNil)
+	c.Assert(actualData.Bytes(), DeepEquals, []byte(data))
+
+	actualMetadata, err := donut.GetObjectMetadata("foo", "obj")
+	c.Assert(err, IsNil)
+	c.Assert(expectedMd5Sum, Equals, actualMetadata["md5"])
+	c.Assert(strconv.Itoa(len(data)), Equals, actualMetadata["size"])
+	c.Assert("1.0", Equals, actualMetadata["version"])
+	_, err = time.Parse(time.RFC3339Nano, actualMetadata["created"])
+	c.Assert(err, IsNil)
+}
+
+// test list objects
+func (s *MySuite) TestMultipleNewObjects(c *C) {
+	root, err := ioutil.TempDir(os.TempDir(), "donut-")
+	c.Assert(err, IsNil)
+	defer os.RemoveAll(root)
+	donut, err := NewDonut("test", createTestNodeDiskMap(root))
+	c.Assert(err, IsNil)
+
+	c.Assert(donut.MakeBucket("foo"), IsNil)
+
+	one := ioutil.NopCloser(bytes.NewReader([]byte("one")))
+	err = donut.PutObject("foo", "obj1", "", one, nil)
+	c.Assert(err, IsNil)
+
+	two := ioutil.NopCloser(bytes.NewReader([]byte("two")))
+	err = donut.PutObject("foo", "obj2", "", two, nil)
+	c.Assert(err, IsNil)
+
+	obj1, size, err := donut.GetObject("foo", "obj1")
+	c.Assert(err, IsNil)
+	c.Assert(size, Equals, int64(len([]byte("one"))))
+
+	var readerBuffer1 bytes.Buffer
+	_, err = io.CopyN(&readerBuffer1, obj1, size)
+	c.Assert(err, IsNil)
+	c.Assert(readerBuffer1.Bytes(), DeepEquals, []byte("one"))
+
+	obj2, size, err := donut.GetObject("foo", "obj2")
+	c.Assert(err, IsNil)
+	c.Assert(size, Equals, int64(len([]byte("two"))))
+
+	var readerBuffer2 bytes.Buffer
+	_, err = io.CopyN(&readerBuffer2, obj2, size)
+	c.Assert(err, IsNil)
+	c.Assert(readerBuffer2.Bytes(), DeepEquals, []byte("two"))
+
+	/// test list of objects
+
+	// test list objects with prefix and delimiter
+	listObjects, prefixes, isTruncated, err := donut.ListObjects("foo", "o", "", "1", 1)
+	c.Assert(err, IsNil)
+	c.Assert(isTruncated, Equals, false)
+	c.Assert(prefixes[0], Equals, "obj1")
+
+	// test list objects with only delimiter
+	listObjects, prefixes, isTruncated, err = donut.ListObjects("foo", "", "", "1", 10)
+	c.Assert(err, IsNil)
+	c.Assert(listObjects[0], Equals, "obj2")
+	c.Assert(isTruncated, Equals, false)
+	c.Assert(prefixes[0], Equals, "obj1")
+
+	// test list objects with only prefix
+	listObjects, _, isTruncated, err = donut.ListObjects("foo", "o", "", "", 10)
+	c.Assert(err, IsNil)
+	c.Assert(isTruncated, Equals, false)
+	c.Assert(listObjects, DeepEquals, []string{"obj1", "obj2"})
+
+	three := ioutil.NopCloser(bytes.NewReader([]byte("three")))
+	err = donut.PutObject("foo", "obj3", "", three, nil)
+	c.Assert(err, IsNil)
+
+	obj3, size, err := donut.GetObject("foo", "obj3")
+	c.Assert(err, IsNil)
+	c.Assert(size, Equals, int64(len([]byte("three"))))
+
+	var readerBuffer3 bytes.Buffer
+	_, err = io.CopyN(&readerBuffer3, obj3, size)
+	c.Assert(err, IsNil)
+	c.Assert(readerBuffer3.Bytes(), DeepEquals, []byte("three"))
+
+	// test list objects with maxkeys
+	listObjects, _, isTruncated, err = donut.ListObjects("foo", "o", "", "", 2)
+	c.Assert(err, IsNil)
+	c.Assert(isTruncated, Equals, true)
+	c.Assert(len(listObjects), Equals, 2)
+}

pkg/storage/donut/management.go

@@ -0,0 +1,76 @@
+package donut
+
+import (
+	"encoding/json"
+	"errors"
+	"path"
+
+	"github.com/minio-io/iodine"
+)
+
+// Heal - heal a donut and fix bad data blocks
+func (d donut) Heal() error {
+	return errors.New("Not Implemented")
+}
+
+// Info - return info about donut configuration
+func (d donut) Info() (nodeDiskMap map[string][]string, err error) {
+	nodeDiskMap = make(map[string][]string)
+	for nodeName, node := range d.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return nil, iodine.New(err, nil)
+		}
+		diskList := make([]string, len(disks))
+		for diskName, disk := range disks {
+			diskList[disk.GetOrder()] = diskName
+		}
+		nodeDiskMap[nodeName] = diskList
+	}
+	return nodeDiskMap, nil
+}
+
+// AttachNode - attach node
+func (d donut) AttachNode(node Node) error {
+	if node == nil {
+		return iodine.New(errors.New("invalid argument"), nil)
+	}
+	d.nodes[node.GetNodeName()] = node
+	return nil
+}
+
+// DetachNode - detach node
+func (d donut) DetachNode(node Node) error {
+	delete(d.nodes, node.GetNodeName())
+	return nil
+}
+
+// SaveConfig - save donut configuration
+func (d donut) SaveConfig() error {
+	nodeDiskMap := make(map[string][]string)
+	for hostname, node := range d.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		for _, disk := range disks {
+			donutConfigPath := path.Join(d.name, donutConfig)
+			donutConfigWriter, err := disk.MakeFile(donutConfigPath)
+			defer donutConfigWriter.Close()
+			if err != nil {
+				return iodine.New(err, nil)
+			}
+			nodeDiskMap[hostname][disk.GetOrder()] = disk.GetPath()
+			jenc := json.NewEncoder(donutConfigWriter)
+			if err := jenc.Encode(nodeDiskMap); err != nil {
+				return iodine.New(err, nil)
+			}
+		}
+	}
+	return nil
+}
+
+// LoadConfig - load configuration
+func (d donut) LoadConfig() error {
+	return errors.New("Not Implemented")
+}

pkg/storage/donut/objectstorage.go

@@ -0,0 +1,203 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"io"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/minio-io/iodine"
+)
+
+// MakeBucket - make a new bucket
+func (d donut) MakeBucket(bucket string) error {
+	if bucket == "" || strings.TrimSpace(bucket) == "" {
+		return iodine.New(errors.New("invalid argument"), nil)
+	}
+	return d.makeDonutBucket(bucket)
+}
+
+// GetBucketMetadata - get bucket metadata
+func (d donut) GetBucketMetadata(bucket string) (map[string]string, error) {
+	err := d.getDonutBuckets()
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	if _, ok := d.buckets[bucket]; !ok {
+		return nil, iodine.New(errors.New("bucket does not exist"), nil)
+	}
+	metadata := make(map[string]string)
+	metadata["name"] = bucket
+	metadata["created"] = time.Now().Format(time.RFC3339Nano) // TODO get this, from whatever is written from SetBucketMetadata
+	return metadata, nil
+}
+
+// SetBucketMetadata - set bucket metadata
+func (d donut) SetBucketMetadata(bucket string, metadata map[string]string) error {
+	return errors.New("Not implemented")
+}
+
+// ListBuckets - return list of buckets
+func (d donut) ListBuckets() (results []string, err error) {
+	err = d.getDonutBuckets()
+	if err != nil {
+		return nil, iodine.New(err, nil)
+	}
+	for name := range d.buckets {
+		results = append(results, name)
+	}
+	sort.Strings(results)
+	return results, nil
+}
+
+// ListObjects - return list of objects
+func (d donut) ListObjects(bucket, prefix, marker, delimiter string, maxkeys int) ([]string, []string, bool, error) {
+	// TODO: Marker is not yet handled please handle it
+	errParams := map[string]string{
+		"bucket":    bucket,
+		"prefix":    prefix,
+		"marker":    marker,
+		"delimiter": delimiter,
+		"maxkeys":   strconv.Itoa(maxkeys),
+	}
+	err := d.getDonutBuckets()
+	if err != nil {
+		return nil, nil, false, iodine.New(err, errParams)
+	}
+	if _, ok := d.buckets[bucket]; !ok {
+		return nil, nil, false, iodine.New(errors.New("bucket does not exist"), errParams)
+	}
+	objectList, err := d.buckets[bucket].ListObjects()
+	if err != nil {
+		return nil, nil, false, iodine.New(err, errParams)
+	}
+	var donutObjects []string
+	for objectName := range objectList {
+		donutObjects = append(donutObjects, objectName)
+	}
+	if maxkeys <= 0 {
+		maxkeys = 1000
+	}
+	if strings.TrimSpace(prefix) != "" {
+		donutObjects = filterPrefix(donutObjects, prefix)
+		donutObjects = removePrefix(donutObjects, prefix)
+	}
+
+	var actualObjects []string
+	var actualPrefixes []string
+	var isTruncated bool
+	if strings.TrimSpace(delimiter) != "" {
+		actualObjects = filterDelimited(donutObjects, delimiter)
+		actualPrefixes = filterNotDelimited(donutObjects, delimiter)
+		actualPrefixes = extractDir(actualPrefixes, delimiter)
+		actualPrefixes = uniqueObjects(actualPrefixes)
+	} else {
+		actualObjects = donutObjects
+	}
+
+	var results []string
+	var commonPrefixes []string
+	for _, objectName := range actualObjects {
+		if len(results) >= maxkeys {
+			isTruncated = true
+			break
+		}
+		results = appendUniq(results, prefix+objectName)
+	}
+	for _, commonPrefix := range actualPrefixes {
+		commonPrefixes = appendUniq(commonPrefixes, prefix+commonPrefix)
+	}
+	sort.Strings(results)
+	sort.Strings(commonPrefixes)
+	return results, commonPrefixes, isTruncated, nil
+}
+
+// PutObject - put object
+func (d donut) PutObject(bucket, object, expectedMD5Sum string, reader io.ReadCloser, metadata map[string]string) error {
+	errParams := map[string]string{
+		"bucket": bucket,
+		"object": object,
+	}
+	if bucket == "" || strings.TrimSpace(bucket) == "" {
+		return iodine.New(errors.New("invalid argument"), errParams)
+	}
+	if object == "" || strings.TrimSpace(object) == "" {
+		return iodine.New(errors.New("invalid argument"), errParams)
+	}
+	err := d.getDonutBuckets()
+	if err != nil {
+		return iodine.New(err, errParams)
+	}
+	if _, ok := d.buckets[bucket]; !ok {
+		return iodine.New(errors.New("bucket does not exist"), nil)
+	}
+	err = d.buckets[bucket].PutObject(object, reader, expectedMD5Sum, metadata)
+	if err != nil {
+		return iodine.New(err, errParams)
+	}
+	return nil
+}
+
+// GetObject - get object
+func (d donut) GetObject(bucket, object string) (reader io.ReadCloser, size int64, err error) {
+	errParams := map[string]string{
+		"bucket": bucket,
+		"object": object,
+	}
+	if bucket == "" || strings.TrimSpace(bucket) == "" {
+		return nil, 0, iodine.New(errors.New("invalid argument"), errParams)
+	}
+	if object == "" || strings.TrimSpace(object) == "" {
+		return nil, 0, iodine.New(errors.New("invalid argument"), errParams)
+	}
+	err = d.getDonutBuckets()
+	if err != nil {
+		return nil, 0, iodine.New(err, nil)
+	}
+	if _, ok := d.buckets[bucket]; !ok {
+		return nil, 0, iodine.New(errors.New("bucket does not exist"), errParams)
+	}
+	return d.buckets[bucket].GetObject(object)
+}
+
+// GetObjectMetadata - get object metadata
+func (d donut) GetObjectMetadata(bucket, object string) (map[string]string, error) {
+	errParams := map[string]string{
+		"bucket": bucket,
+		"object": object,
+	}
+	err := d.getDonutBuckets()
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	if _, ok := d.buckets[bucket]; !ok {
+		return nil, iodine.New(errors.New("bucket does not exist"), errParams)
+	}
+	objectList, err := d.buckets[bucket].ListObjects()
+	if err != nil {
+		return nil, iodine.New(err, errParams)
+	}
+	donutObject, ok := objectList[object]
+	if !ok {
+		return nil, iodine.New(errors.New("object does not exist"), errParams)
+	}
+	return donutObject.GetObjectMetadata()
+}

pkg/storage/donut/objectstorage_internal.go

@@ -0,0 +1,86 @@
+/*
+ * Minimalist Object Storage, (C) 2015 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package donut
+
+import (
+	"errors"
+	"fmt"
+	"path"
+	"strings"
+
+	"github.com/minio-io/iodine"
+)
+
+func (d donut) makeDonutBucket(bucketName string) error {
+	err := d.getDonutBuckets()
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	if _, ok := d.buckets[bucketName]; ok {
+		return iodine.New(errors.New("bucket exists"), nil)
+	}
+	bucket, err := NewBucket(bucketName, d.name, d.nodes)
+	if err != nil {
+		return iodine.New(err, nil)
+	}
+	nodeNumber := 0
+	d.buckets[bucketName] = bucket
+	for _, node := range d.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		for _, disk := range disks {
+			bucketSlice := fmt.Sprintf("%s$%d$%d", bucketName, nodeNumber, disk.GetOrder())
+			err := disk.MakeDir(path.Join(d.name, bucketSlice))
+			if err != nil {
+				return iodine.New(err, nil)
+			}
+		}
+		nodeNumber = nodeNumber + 1
+	}
+	return nil
+}
+
+func (d donut) getDonutBuckets() error {
+	for _, node := range d.nodes {
+		disks, err := node.ListDisks()
+		if err != nil {
+			return iodine.New(err, nil)
+		}
+		for _, disk := range disks {
+			dirs, err := disk.ListDir(d.name)
+			if err != nil {
+				return iodine.New(err, nil)
+			}
+			for _, dir := range dirs {
+				splitDir := strings.Split(dir.Name(), "$")
+				if len(splitDir) < 3 {
+					return iodine.New(errors.New("corrupted backend"), nil)
+				}
+				bucketName := splitDir[0]
+				// we dont need this NewBucket once we cache from makeDonutBucket()
+				bucket, err := NewBucket(bucketName, d.name, d.nodes)
+				if err != nil {
+					return iodine.New(err, nil)
+				}
+				d.buckets[bucketName] = bucket
+			}
+		}
+	}
+	return nil
+}