forked from grafana/loki
/
gzip.go
595 lines (483 loc) · 12.6 KB
/
gzip.go
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package chunkenc
import (
"bufio"
"bytes"
"encoding/binary"
"fmt"
"hash"
"hash/crc32"
"io"
"time"
"github.com/grafana/loki/pkg/iter"
"github.com/grafana/loki/pkg/logproto"
"github.com/grafana/loki/pkg/logql"
"github.com/pkg/errors"
)
const blocksPerChunk = 10
var (
magicNumber = uint32(0x12EE56A)
chunkFormatV1 = byte(1)
)
// The table gets initialized with sync.Once but may still cause a race
// with any other use of the crc32 package anywhere. Thus we initialize it
// before.
var castagnoliTable *crc32.Table
func init() {
castagnoliTable = crc32.MakeTable(crc32.Castagnoli)
}
// newCRC32 initializes a CRC32 hash with a preconfigured polynomial, so the
// polynomial may be easily changed in one location at a later time, if necessary.
func newCRC32() hash.Hash32 {
return crc32.New(castagnoliTable)
}
// MemChunk implements compressed log chunks.
type MemChunk struct {
// The number of uncompressed bytes per block.
blockSize int
// The finished blocks.
blocks []block
// Current in-mem block being appended to.
head *headBlock
encoding Encoding
cPool CompressionPool
}
type block struct {
// This is compressed bytes.
b []byte
numEntries int
mint, maxt int64
offset int // The offset of the block in the chunk.
}
// This block holds the un-compressed entries. Once it has enough data, this is
// emptied into a block with only compressed entries.
type headBlock struct {
// This is the list of raw entries.
entries []entry
size int // size of uncompressed bytes.
mint, maxt int64
}
func (hb *headBlock) isEmpty() bool {
return len(hb.entries) == 0
}
func (hb *headBlock) append(ts int64, line string) error {
if !hb.isEmpty() && hb.maxt > ts {
return ErrOutOfOrder
}
hb.entries = append(hb.entries, entry{ts, line})
if hb.mint == 0 || hb.mint > ts {
hb.mint = ts
}
hb.maxt = ts
hb.size += len(line)
return nil
}
func (hb *headBlock) serialise(pool CompressionPool) ([]byte, error) {
buf := &bytes.Buffer{}
encBuf := make([]byte, binary.MaxVarintLen64)
compressedWriter := pool.GetWriter(buf)
for _, logEntry := range hb.entries {
n := binary.PutVarint(encBuf, logEntry.t)
_, err := compressedWriter.Write(encBuf[:n])
if err != nil {
return nil, errors.Wrap(err, "appending entry")
}
n = binary.PutUvarint(encBuf, uint64(len(logEntry.s)))
_, err = compressedWriter.Write(encBuf[:n])
if err != nil {
return nil, errors.Wrap(err, "appending entry")
}
_, err = compressedWriter.Write([]byte(logEntry.s))
if err != nil {
return nil, errors.Wrap(err, "appending entry")
}
}
if err := compressedWriter.Close(); err != nil {
return nil, errors.Wrap(err, "flushing pending compress buffer")
}
pool.PutWriter(compressedWriter)
return buf.Bytes(), nil
}
type entry struct {
t int64
s string
}
// NewMemChunkSize returns a new in-mem chunk.
// Mainly for config push size.
func NewMemChunkSize(enc Encoding, blockSize int) *MemChunk {
c := &MemChunk{
blockSize: blockSize, // The blockSize in bytes.
blocks: []block{},
head: &headBlock{},
encoding: enc,
}
switch enc {
case EncGZIP:
c.cPool = &Gzip
default:
panic("unknown encoding")
}
return c
}
// NewMemChunk returns a new in-mem chunk for query.
func NewMemChunk(enc Encoding) *MemChunk {
return NewMemChunkSize(enc, 256*1024)
}
// NewByteChunk returns a MemChunk on the passed bytes.
func NewByteChunk(b []byte) (*MemChunk, error) {
bc := &MemChunk{
cPool: &Gzip,
encoding: EncGZIP,
head: &headBlock{}, // Dummy, empty headblock.
}
db := decbuf{b: b}
// Verify the header.
m, version := db.be32(), db.byte()
if db.err() != nil {
return nil, errors.Wrap(db.err(), "verifying header")
}
if m != magicNumber {
return nil, errors.Errorf("invalid magic number %x", m)
}
if version != 1 {
return nil, errors.Errorf("invalid version %d", version)
}
metasOffset := binary.BigEndian.Uint64(b[len(b)-8:])
mb := b[metasOffset : len(b)-(8+4)] // storing the metasOffset + checksum of meta
db = decbuf{b: mb}
expCRC := binary.BigEndian.Uint32(b[len(b)-(8+4):])
if expCRC != db.crc32() {
return nil, ErrInvalidChecksum
}
// Read the number of blocks.
num := db.uvarint()
bc.blocks = make([]block, 0, num)
for i := 0; i < num; i++ {
blk := block{}
// Read #entries.
blk.numEntries = db.uvarint()
// Read mint, maxt.
blk.mint = db.varint64()
blk.maxt = db.varint64()
// Read offset and length.
blk.offset = db.uvarint()
l := db.uvarint()
blk.b = b[blk.offset : blk.offset+l]
// Verify checksums.
expCRC := binary.BigEndian.Uint32(b[blk.offset+l:])
if expCRC != crc32.Checksum(blk.b, castagnoliTable) {
return bc, ErrInvalidChecksum
}
bc.blocks = append(bc.blocks, blk)
if db.err() != nil {
return nil, errors.Wrap(db.err(), "decoding block meta")
}
}
return bc, nil
}
// Bytes implements Chunk.
func (c *MemChunk) Bytes() ([]byte, error) {
if c.head != nil {
// When generating the bytes, we need to flush the data held in-buffer.
if err := c.cut(); err != nil {
return nil, err
}
}
crc32Hash := newCRC32()
buf := bytes.NewBuffer(nil)
offset := 0
eb := encbuf{b: make([]byte, 0, 1<<10)}
// Write the header (magicNum + version).
eb.putBE32(magicNumber)
eb.putByte(chunkFormatV1)
n, err := buf.Write(eb.get())
if err != nil {
return buf.Bytes(), errors.Wrap(err, "write blockMeta #entries")
}
offset += n
// Write Blocks.
for i, b := range c.blocks {
c.blocks[i].offset = offset
eb.reset()
eb.putBytes(b.b)
eb.putHash(crc32Hash)
n, err := buf.Write(eb.get())
if err != nil {
return buf.Bytes(), errors.Wrap(err, "write block")
}
offset += n
}
metasOffset := offset
// Write the number of blocks.
eb.reset()
eb.putUvarint(len(c.blocks))
// Write BlockMetas.
for _, b := range c.blocks {
eb.putUvarint(b.numEntries)
eb.putVarint64(b.mint)
eb.putVarint64(b.maxt)
eb.putUvarint(b.offset)
eb.putUvarint(len(b.b))
}
eb.putHash(crc32Hash)
_, err = buf.Write(eb.get())
if err != nil {
return buf.Bytes(), errors.Wrap(err, "write block metas")
}
// Write the metasOffset.
eb.reset()
eb.putBE64int(metasOffset)
_, err = buf.Write(eb.get())
if err != nil {
return buf.Bytes(), errors.Wrap(err, "write metasOffset")
}
return buf.Bytes(), nil
}
// Encoding implements Chunk.
func (c *MemChunk) Encoding() Encoding {
return c.encoding
}
// Size implements Chunk.
func (c *MemChunk) Size() int {
ne := 0
for _, blk := range c.blocks {
ne += blk.numEntries
}
if !c.head.isEmpty() {
ne += len(c.head.entries)
}
return ne
}
// SpaceFor implements Chunk.
func (c *MemChunk) SpaceFor(*logproto.Entry) bool {
return len(c.blocks) < blocksPerChunk
}
// Append implements Chunk.
func (c *MemChunk) Append(entry *logproto.Entry) error {
entryTimestamp := entry.Timestamp.UnixNano()
// If the head block is empty but there are cut blocks, we have to make
// sure the new entry is not out of order compared to the previous block
if c.head.isEmpty() && len(c.blocks) > 0 && c.blocks[len(c.blocks)-1].maxt > entryTimestamp {
return ErrOutOfOrder
}
if err := c.head.append(entryTimestamp, entry.Line); err != nil {
return err
}
if c.head.size >= c.blockSize {
return c.cut()
}
return nil
}
// Close implements Chunk.
// TODO: Fix this to check edge cases.
func (c *MemChunk) Close() error {
return c.cut()
}
// cut a new block and add it to finished blocks.
func (c *MemChunk) cut() error {
if c.head.isEmpty() {
return nil
}
b, err := c.head.serialise(c.cPool)
if err != nil {
return err
}
c.blocks = append(c.blocks, block{
b: b,
numEntries: len(c.head.entries),
mint: c.head.mint,
maxt: c.head.maxt,
})
c.head.entries = c.head.entries[:0]
c.head.mint = 0 // Will be set on first append.
c.head.size = 0
return nil
}
// Bounds implements Chunk.
func (c *MemChunk) Bounds() (fromT, toT time.Time) {
var from, to int64
if len(c.blocks) > 0 {
from = c.blocks[0].mint
to = c.blocks[len(c.blocks)-1].maxt
}
if !c.head.isEmpty() {
if from == 0 || from > c.head.mint {
from = c.head.mint
}
if to < c.head.maxt {
to = c.head.maxt
}
}
return time.Unix(0, from), time.Unix(0, to)
}
// Iterator implements Chunk.
func (c *MemChunk) Iterator(mintT, maxtT time.Time, direction logproto.Direction, filter logql.Filter) (iter.EntryIterator, error) {
mint, maxt := mintT.UnixNano(), maxtT.UnixNano()
its := make([]iter.EntryIterator, 0, len(c.blocks)+1)
for _, b := range c.blocks {
if maxt > b.mint && b.maxt > mint {
its = append(its, b.iterator(c.cPool, filter))
}
}
if !c.head.isEmpty() {
its = append(its, c.head.iterator(mint, maxt, filter))
}
iterForward := iter.NewTimeRangedIterator(
iter.NewNonOverlappingIterator(its, ""),
time.Unix(0, mint),
time.Unix(0, maxt),
)
if direction == logproto.FORWARD {
return iterForward, nil
}
return iter.NewEntryIteratorBackward(iterForward)
}
func (b block) iterator(pool CompressionPool, filter logql.Filter) iter.EntryIterator {
if len(b.b) == 0 {
return emptyIterator
}
return newBufferedIterator(pool, b.b, filter)
}
func (hb *headBlock) iterator(mint, maxt int64, filter logql.Filter) iter.EntryIterator {
if hb.isEmpty() || (maxt < hb.mint || hb.maxt < mint) {
return emptyIterator
}
// We are doing a copy everytime, this is because b.entries could change completely,
// the alternate would be that we allocate a new b.entries everytime we cut a block,
// but the tradeoff is that queries to near-realtime data would be much lower than
// cutting of blocks.
entries := make([]entry, 0, len(hb.entries))
for _, e := range hb.entries {
if filter == nil || filter([]byte(e.s)) {
entries = append(entries, e)
}
}
if len(entries) == 0 {
return emptyIterator
}
return &listIterator{
entries: entries,
}
}
var emptyIterator = &listIterator{}
type listIterator struct {
entries []entry
cur entry
}
func (li *listIterator) Next() bool {
if len(li.entries) > 0 {
li.cur = li.entries[0]
li.entries = li.entries[1:]
return true
}
return false
}
func (li *listIterator) Entry() logproto.Entry {
return logproto.Entry{
Timestamp: time.Unix(0, li.cur.t),
Line: li.cur.s,
}
}
func (li *listIterator) Error() error { return nil }
func (li *listIterator) Close() error { return nil }
func (li *listIterator) Labels() string { return "" }
type bufferedIterator struct {
s *bufio.Reader
reader CompressionReader
pool CompressionPool
cur logproto.Entry
err error
buf []byte // The buffer for a single entry.
decBuf []byte // The buffer for decoding the lengths.
closed bool
filter logql.Filter
}
func newBufferedIterator(pool CompressionPool, b []byte, filter logql.Filter) *bufferedIterator {
r := pool.GetReader(bytes.NewBuffer(b))
return &bufferedIterator{
s: BufReaderPool.Get(r),
reader: r,
pool: pool,
filter: filter,
decBuf: make([]byte, binary.MaxVarintLen64),
}
}
func (si *bufferedIterator) Next() bool {
for {
ts, line, ok := si.moveNext()
if !ok {
si.Close()
return false
}
if si.filter != nil && !si.filter(line) {
continue
}
si.cur.Line = string(line)
si.cur.Timestamp = time.Unix(0, ts)
return true
}
}
// moveNext moves the buffer to the next entry
func (si *bufferedIterator) moveNext() (int64, []byte, bool) {
ts, err := binary.ReadVarint(si.s)
if err != nil {
if err != io.EOF {
si.err = err
}
return 0, nil, false
}
l, err := binary.ReadUvarint(si.s)
if err != nil {
if err != io.EOF {
si.err = err
return 0, nil, false
}
}
lineSize := int(l)
// If the buffer is not yet initialize or too small, we get a new one.
if si.buf == nil || lineSize > cap(si.buf) {
// in case of a replacement we replace back the buffer in the pool
if si.buf != nil {
BytesBufferPool.Put(si.buf)
}
si.buf = BytesBufferPool.Get(lineSize).([]byte)
if lineSize > cap(si.buf) {
fmt.Println("oups ", lineSize, " ", len(si.buf), " ", cap(si.buf))
}
}
// Then process reading the line.
n, err := si.s.Read(si.buf[:lineSize])
if err != nil && err != io.EOF {
si.err = err
return 0, nil, false
}
for n < lineSize {
r, err := si.s.Read(si.buf[n:lineSize])
if err != nil {
si.err = err
return 0, nil, false
}
n += r
}
return ts, si.buf[:lineSize], true
}
func (si *bufferedIterator) Entry() logproto.Entry {
return si.cur
}
func (si *bufferedIterator) Error() error { return si.err }
func (si *bufferedIterator) Close() error {
if !si.closed {
si.closed = true
si.pool.PutReader(si.reader)
BufReaderPool.Put(si.s)
if si.buf != nil {
BytesBufferPool.Put(si.buf)
}
si.s = nil
si.buf = nil
si.decBuf = nil
si.reader = nil
return si.err
}
return si.err
}
func (si *bufferedIterator) Labels() string { return "" }