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traefik/vendor/github.com/Shopify/sarama/message.go
2018-01-10 17:48:04 +01:00

217 lines
4.8 KiB
Go

package sarama
import (
"bytes"
"compress/gzip"
"fmt"
"io/ioutil"
"time"
"github.com/eapache/go-xerial-snappy"
"github.com/pierrec/lz4"
)
// CompressionCodec represents the various compression codecs recognized by Kafka in messages.
type CompressionCodec int8
// only the last two bits are really used
const compressionCodecMask int8 = 0x03
const (
CompressionNone CompressionCodec = 0
CompressionGZIP CompressionCodec = 1
CompressionSnappy CompressionCodec = 2
CompressionLZ4 CompressionCodec = 3
)
type Message struct {
Codec CompressionCodec // codec used to compress the message contents
Key []byte // the message key, may be nil
Value []byte // the message contents
Set *MessageSet // the message set a message might wrap
Version int8 // v1 requires Kafka 0.10
Timestamp time.Time // the timestamp of the message (version 1+ only)
compressedCache []byte
compressedSize int // used for computing the compression ratio metrics
}
func (m *Message) encode(pe packetEncoder) error {
pe.push(&crc32Field{})
pe.putInt8(m.Version)
attributes := int8(m.Codec) & compressionCodecMask
pe.putInt8(attributes)
if m.Version >= 1 {
timestamp := int64(-1)
if !m.Timestamp.Before(time.Unix(0, 0)) {
timestamp = m.Timestamp.UnixNano() / int64(time.Millisecond)
} else if !m.Timestamp.IsZero() {
return PacketEncodingError{fmt.Sprintf("invalid timestamp (%v)", m.Timestamp)}
}
pe.putInt64(timestamp)
}
err := pe.putBytes(m.Key)
if err != nil {
return err
}
var payload []byte
if m.compressedCache != nil {
payload = m.compressedCache
m.compressedCache = nil
} else if m.Value != nil {
switch m.Codec {
case CompressionNone:
payload = m.Value
case CompressionGZIP:
var buf bytes.Buffer
writer := gzip.NewWriter(&buf)
if _, err = writer.Write(m.Value); err != nil {
return err
}
if err = writer.Close(); err != nil {
return err
}
m.compressedCache = buf.Bytes()
payload = m.compressedCache
case CompressionSnappy:
tmp := snappy.Encode(m.Value)
m.compressedCache = tmp
payload = m.compressedCache
case CompressionLZ4:
var buf bytes.Buffer
writer := lz4.NewWriter(&buf)
if _, err = writer.Write(m.Value); err != nil {
return err
}
if err = writer.Close(); err != nil {
return err
}
m.compressedCache = buf.Bytes()
payload = m.compressedCache
default:
return PacketEncodingError{fmt.Sprintf("unsupported compression codec (%d)", m.Codec)}
}
// Keep in mind the compressed payload size for metric gathering
m.compressedSize = len(payload)
}
if err = pe.putBytes(payload); err != nil {
return err
}
return pe.pop()
}
func (m *Message) decode(pd packetDecoder) (err error) {
err = pd.push(&crc32Field{})
if err != nil {
return err
}
m.Version, err = pd.getInt8()
if err != nil {
return err
}
if m.Version > 1 {
return PacketDecodingError{fmt.Sprintf("unknown magic byte (%v)", m.Version)}
}
attribute, err := pd.getInt8()
if err != nil {
return err
}
m.Codec = CompressionCodec(attribute & compressionCodecMask)
if m.Version == 1 {
millis, err := pd.getInt64()
if err != nil {
return err
}
// negative timestamps are invalid, in these cases we should return
// a zero time
timestamp := time.Time{}
if millis >= 0 {
timestamp = time.Unix(millis/1000, (millis%1000)*int64(time.Millisecond))
}
m.Timestamp = timestamp
}
m.Key, err = pd.getBytes()
if err != nil {
return err
}
m.Value, err = pd.getBytes()
if err != nil {
return err
}
// Required for deep equal assertion during tests but might be useful
// for future metrics about the compression ratio in fetch requests
m.compressedSize = len(m.Value)
switch m.Codec {
case CompressionNone:
// nothing to do
case CompressionGZIP:
if m.Value == nil {
break
}
reader, err := gzip.NewReader(bytes.NewReader(m.Value))
if err != nil {
return err
}
if m.Value, err = ioutil.ReadAll(reader); err != nil {
return err
}
if err := m.decodeSet(); err != nil {
return err
}
case CompressionSnappy:
if m.Value == nil {
break
}
if m.Value, err = snappy.Decode(m.Value); err != nil {
return err
}
if err := m.decodeSet(); err != nil {
return err
}
case CompressionLZ4:
if m.Value == nil {
break
}
reader := lz4.NewReader(bytes.NewReader(m.Value))
if m.Value, err = ioutil.ReadAll(reader); err != nil {
return err
}
if err := m.decodeSet(); err != nil {
return err
}
default:
return PacketDecodingError{fmt.Sprintf("invalid compression specified (%d)", m.Codec)}
}
return pd.pop()
}
// decodes a message set from a previousy encoded bulk-message
func (m *Message) decodeSet() (err error) {
pd := realDecoder{raw: m.Value}
m.Set = &MessageSet{}
return m.Set.decode(&pd)
}