forked from twmb/franz-go
/
compression.go
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/
compression.go
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package kgo
import (
"bytes"
"compress/gzip"
"encoding/binary"
"errors"
"io/ioutil"
"runtime"
"sync"
"github.com/klauspost/compress/s2"
"github.com/klauspost/compress/zstd"
"github.com/pierrec/lz4/v4"
)
// sliceWriter a reusable slice as an io.Writer
type sliceWriter struct{ inner []byte }
func (s *sliceWriter) Write(p []byte) (int, error) {
s.inner = append(s.inner, p...)
return len(p), nil
}
var sliceWriters = sync.Pool{New: func() any { r := make([]byte, 8<<10); return &sliceWriter{inner: r} }}
type codecType int8
const (
codecNone codecType = iota
codecGzip
codecSnappy
codecLZ4
codecZstd
)
// CompressionCodec configures how records are compressed before being sent.
//
// Records are compressed within individual topics and partitions, inside of a
// RecordBatch. All records in a RecordBatch are compressed into one record
// for that batch.
type CompressionCodec struct {
codec codecType
level int8
}
// NoCompression is a compression option that avoids compression. This can
// always be used as a fallback compression.
func NoCompression() CompressionCodec { return CompressionCodec{codecNone, 0} }
// GzipCompression enables gzip compression with the default compression level.
func GzipCompression() CompressionCodec { return CompressionCodec{codecGzip, gzip.DefaultCompression} }
// SnappyCompression enables snappy compression.
func SnappyCompression() CompressionCodec { return CompressionCodec{codecSnappy, 0} }
// Lz4Compression enables lz4 compression with the fastest compression level.
func Lz4Compression() CompressionCodec { return CompressionCodec{codecLZ4, 0} }
// ZstdCompression enables zstd compression with the default compression level.
func ZstdCompression() CompressionCodec { return CompressionCodec{codecZstd, 0} }
// WithLevel changes the compression codec's "level", effectively allowing for
// higher or lower compression ratios at the expense of CPU speed.
//
// For the zstd package, the level is a typed int; simply convert the type back
// to an int for this function.
//
// If the level is invalid, compressors just use a default level.
func (c CompressionCodec) WithLevel(level int) CompressionCodec {
if level > 127 {
level = 127 // lz4 could theoretically be large, I guess
}
c.level = int8(level)
return c
}
type compressor struct {
options []codecType
gzPool sync.Pool
lz4Pool sync.Pool
zstdPool sync.Pool
}
func newCompressor(codecs ...CompressionCodec) (*compressor, error) {
if len(codecs) == 0 {
return nil, nil
}
used := make(map[codecType]bool) // we keep one type of codec per CompressionCodec
var keepIdx int
for _, codec := range codecs {
if _, exists := used[codec.codec]; exists {
continue
}
used[codec.codec] = true
codecs[keepIdx] = codec
keepIdx++
}
codecs = codecs[:keepIdx]
for _, codec := range codecs {
if codec.codec < 0 || codec.codec > 4 {
return nil, errors.New("unknown compression codec")
}
}
c := new(compressor)
out:
for _, codec := range codecs {
c.options = append(c.options, codec.codec)
switch codec.codec {
case codecNone:
break out
case codecGzip:
level := gzip.DefaultCompression
if codec.level != 0 {
if _, err := gzip.NewWriterLevel(nil, int(codec.level)); err != nil {
level = int(codec.level)
}
}
c.gzPool = sync.Pool{New: func() any { c, _ := gzip.NewWriterLevel(nil, level); return c }}
case codecSnappy: // (no pool needed for snappy)
case codecLZ4:
level := codec.level
if level < 0 {
level = 0 // 0 == lz4.Fast
}
fn := func() any { return lz4.NewWriter(new(bytes.Buffer)) }
w := lz4.NewWriter(new(bytes.Buffer))
if err := w.Apply(lz4.CompressionLevelOption(lz4.CompressionLevel(level))); err == nil {
fn = func() any {
w := lz4.NewWriter(new(bytes.Buffer))
w.Apply(lz4.CompressionLevelOption(lz4.CompressionLevel(level)))
return w
}
}
w.Close()
c.lz4Pool = sync.Pool{New: fn}
case codecZstd:
opts := []zstd.EOption{
zstd.WithWindowSize(64 << 10),
zstd.WithEncoderConcurrency(1),
zstd.WithZeroFrames(true),
}
fn := func() any {
zstdEnc, _ := zstd.NewWriter(nil, opts...)
r := &zstdEncoder{zstdEnc}
runtime.SetFinalizer(r, func(r *zstdEncoder) { r.inner.Close() })
return r
}
zstdEnc, err := zstd.NewWriter(nil, append(opts, zstd.WithEncoderLevel(zstd.EncoderLevel(codec.level)))...)
if err == nil {
zstdEnc.Close()
opts = append(opts, zstd.WithEncoderLevel(zstd.EncoderLevel(codec.level)))
}
c.zstdPool = sync.Pool{New: fn}
}
}
if c.options[0] == codecNone {
return nil, nil // first codec was passthrough
}
return c, nil
}
type zstdEncoder struct {
inner *zstd.Encoder
}
// Compress compresses src to buf, returning buf's inner slice once done or nil
// if an error is encountered.
//
// The writer should be put back to its pool after the returned slice is done
// being used.
func (c *compressor) compress(dst *sliceWriter, src []byte, produceRequestVersion int16) ([]byte, codecType) {
dst.inner = dst.inner[:0]
var use codecType
for _, option := range c.options {
if option == codecZstd && produceRequestVersion < 7 {
continue
}
use = option
break
}
switch use {
case codecNone:
return src, 0
case codecGzip:
gz := c.gzPool.Get().(*gzip.Writer)
defer c.gzPool.Put(gz)
gz.Reset(dst)
if _, err := gz.Write(src); err != nil {
return nil, -1
}
if err := gz.Close(); err != nil {
return nil, -1
}
case codecSnappy:
dst.inner = s2.EncodeSnappy(dst.inner[:cap(dst.inner)], src)
case codecLZ4:
lz := c.lz4Pool.Get().(*lz4.Writer)
defer c.lz4Pool.Put(lz)
lz.Reset(dst)
if _, err := lz.Write(src); err != nil {
return nil, -1
}
if err := lz.Close(); err != nil {
return nil, -1
}
case codecZstd:
zstdEnc := c.zstdPool.Get().(*zstdEncoder)
defer c.zstdPool.Put(zstdEnc)
dst.inner = zstdEnc.inner.EncodeAll(src, dst.inner)
}
return dst.inner, use
}
type decompressor struct {
ungzPool sync.Pool
unlz4Pool sync.Pool
unzstdPool sync.Pool
}
func newDecompressor() *decompressor {
d := &decompressor{
ungzPool: sync.Pool{
New: func() any { return new(gzip.Reader) },
},
unlz4Pool: sync.Pool{
New: func() any { return lz4.NewReader(nil) },
},
unzstdPool: sync.Pool{
New: func() any {
zstdDec, _ := zstd.NewReader(nil,
zstd.WithDecoderLowmem(true),
zstd.WithDecoderConcurrency(1),
)
r := &zstdDecoder{zstdDec}
runtime.SetFinalizer(r, func(r *zstdDecoder) {
r.inner.Close()
})
return r
},
},
}
return d
}
type zstdDecoder struct {
inner *zstd.Decoder
}
func (d *decompressor) decompress(src []byte, codec byte) ([]byte, error) {
switch codec {
case 0:
return src, nil
case 1:
ungz := d.ungzPool.Get().(*gzip.Reader)
defer d.ungzPool.Put(ungz)
if err := ungz.Reset(bytes.NewReader(src)); err != nil {
return nil, err
}
return ioutil.ReadAll(ungz)
case 2:
if len(src) > 16 && bytes.HasPrefix(src, xerialPfx) {
return xerialDecode(src)
}
return s2.Decode(nil, src)
case 3:
unlz4 := d.unlz4Pool.Get().(*lz4.Reader)
defer d.unlz4Pool.Put(unlz4)
unlz4.Reset(bytes.NewReader(src))
return ioutil.ReadAll(unlz4)
case 4:
unzstd := d.unzstdPool.Get().(*zstdDecoder)
defer d.unzstdPool.Put(unzstd)
return unzstd.inner.DecodeAll(src, nil)
default:
return nil, errors.New("unknown compression codec")
}
}
var xerialPfx = []byte{130, 83, 78, 65, 80, 80, 89, 0}
var errMalformedXerial = errors.New("malformed xerial framing")
func xerialDecode(src []byte) ([]byte, error) {
// bytes 0-8: xerial header
// bytes 8-16: xerial version
// everything after: uint32 chunk size, snappy chunk
// we come into this function knowing src is at least 16
src = src[16:]
var dst, chunk []byte
var err error
for len(src) > 0 {
if len(src) < 4 {
return nil, errMalformedXerial
}
size := int32(binary.BigEndian.Uint32(src))
src = src[4:]
if size < 0 || len(src) < int(size) {
return nil, errMalformedXerial
}
if chunk, err = s2.Decode(chunk[:cap(chunk)], src[:size]); err != nil {
return nil, err
}
src = src[size:]
dst = append(dst, chunk...)
}
return dst, nil
}