Erasure layer now writes using new technique

This commit is contained in:
Frederick F. Kautz IV 2015-03-06 16:37:44 -08:00
parent 15552a59f9
commit 856e0100c0
3 changed files with 108 additions and 119 deletions

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@ -0,0 +1,98 @@
/*
* Mini 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 erasure1
import (
"bytes"
"encoding/binary"
"encoding/gob"
"errors"
"io"
)
// DataHeader represents the structure serialized to gob.
type DataHeader struct {
// object + block stored
Key string
// chunk index of encoded block
ChunkIndex uint8
// Original Length of the block output
OriginalLength uint32
// Data Blocks
EncoderK uint8
// Parity Blocks
EncoderM uint8
// Matrix Technique
EncoderTechnique EncoderTechnique
}
// EncoderTechnique specified the Matrix type used in encoding
type EncoderTechnique int
const (
// Vandermonde matrix type
Vandermonde EncoderTechnique = iota
// Cauchy matrix type
Cauchy
)
// validate populated header
func validateHeader(header DataHeader) error {
if header.Key == "" {
return errors.New("Empty Key")
}
if header.EncoderTechnique > 1 {
return errors.New("Invalid encoder technique")
}
return nil
}
// WriteData returns error upon any failure
func Write(target io.Writer, key string, part uint8, length uint32, k, m uint8, technique EncoderTechnique, data io.Reader) error {
header := DataHeader{
Key: key,
ChunkIndex: part,
OriginalLength: length,
EncoderK: k,
EncoderM: m,
EncoderTechnique: technique,
}
if err := validateHeader(header); err != nil {
return err
}
var headerBuffer bytes.Buffer
// encode header
encoder := gob.NewEncoder(&headerBuffer)
encoder.Encode(header)
// write version
binary.Write(target, binary.LittleEndian, uint32(1))
// write encoded header
if _, err := io.Copy(target, &headerBuffer); err != nil {
return err
}
// write data
if _, err := io.Copy(target, data); err != nil {
return err
}
return nil
}

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@ -14,7 +14,7 @@
* limitations under the License.
*/
package erasure
package erasure1
import (
"bytes"
@ -35,19 +35,16 @@ var _ = Suite(&MySuite{})
func (s *MySuite) TestSingleWrite(c *C) {
var testBuffer bytes.Buffer
testData := "Hello, World"
encoderParams := EncoderParams{
Length: uint32(len(testData)),
K: 8,
M: 8,
Technique: Cauchy,
testHeader := DataHeader{
Key: "testobj",
ChunkIndex: 1,
OriginalLength: uint32(len(testData)),
EncoderK: 8,
EncoderM: 8,
EncoderTechnique: Cauchy,
}
metadata := make(Metadata)
metadata["Content-Type"] = "application/octet-stream"
metadata["Content-MD5"] = "testing"
header := NewHeader("testobj", 1, metadata, encoderParams)
err := WriteData(&testBuffer, header, bytes.NewBufferString(testData))
err := Write(&testBuffer, testHeader.Key, testHeader.ChunkIndex, testHeader.OriginalLength, testHeader.EncoderK, testHeader.EncoderM, testHeader.EncoderTechnique, bytes.NewBufferString(testData))
c.Assert(err, IsNil)
actualVersion := make([]byte, 4)
@ -60,7 +57,7 @@ func (s *MySuite) TestSingleWrite(c *C) {
decoder := gob.NewDecoder(&testBuffer)
decoder.Decode(&actualHeader)
c.Assert(actualHeader, DeepEquals, header)
c.Assert(actualHeader, DeepEquals, testHeader)
var actualData bytes.Buffer

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@ -1,106 +0,0 @@
/*
* Mini 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 erasure
import (
"bytes"
"encoding/binary"
"encoding/gob"
"fmt"
"io"
)
// Metadata map
type Metadata map[string]string
// DataHeader struct
type DataHeader struct {
Key string
Part uint8
Metadata Metadata
EncoderParams EncoderParams
}
// EncoderTechnique type
type EncoderTechnique int
// EncoderTechniques
const (
Vandermonde EncoderTechnique = iota
Cauchy
)
// EncoderParams struct
type EncoderParams struct {
Length uint32
K uint8
M uint8
Technique EncoderTechnique
}
// NewHeader populate new header
func NewHeader(key string, part uint8, metadata Metadata, encoderParams EncoderParams) DataHeader {
header := DataHeader{}
header.Key = key
header.Part = part
header.Metadata = metadata
header.EncoderParams = EncoderParams{
Length: encoderParams.Length,
K: encoderParams.K,
M: encoderParams.M,
Technique: encoderParams.Technique,
}
return header
}
// ValidateHeader validate populated header
func ValidateHeader(header DataHeader) bool {
if header.Key == "" || header.Part < 0 || len(header.Metadata) < 2 {
return false
}
if header.EncoderParams.Length < 0 || header.EncoderParams.Technique > 1 {
return false
}
return true
}
// WriteData write data, returns error upon any failure
func WriteData(target io.Writer, header DataHeader, data io.Reader) error {
if !ValidateHeader(header) {
return fmt.Errorf("Invalid header")
}
var headerBuffer bytes.Buffer
// encode header
encoder := gob.NewEncoder(&headerBuffer)
encoder.Encode(header)
// write version
binary.Write(target, binary.LittleEndian, uint32(1))
// write encoded header
if _, err := io.Copy(target, &headerBuffer); err != nil {
return err
}
// write data
if _, err := io.Copy(target, data); err != nil {
return err
}
return nil
}