prometheus/tsdb/tombstones/tombstones.go

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// Copyright 2017 The Prometheus Authors
// 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 tombstones
import (
"encoding/binary"
"fmt"
"hash"
"hash/crc32"
"io/ioutil"
"os"
"path/filepath"
"sort"
"sync"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/prometheus/tsdb/encoding"
tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
"github.com/prometheus/prometheus/tsdb/fileutil"
)
const TombstonesFilename = "tombstones"
const (
// MagicTombstone is 4 bytes at the head of a tombstone file.
MagicTombstone = 0x0130BA30
tombstoneFormatV1 = 1
tombstonesHeaderSize = 5
)
// 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)
}
// Reader gives access to tombstone intervals by series reference.
type Reader interface {
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// Get returns deletion intervals for the series with the given reference.
Get(ref uint64) (Intervals, error)
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// Iter calls the given function for each encountered interval.
Iter(func(uint64, Intervals) error) error
// Total returns the total count of tombstones.
Total() uint64
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// Close any underlying resources
Close() error
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}
func WriteFile(logger log.Logger, dir string, tr Reader) (int64, error) {
path := filepath.Join(dir, TombstonesFilename)
tmp := path + ".tmp"
hash := newCRC32()
var size int
f, err := os.Create(tmp)
if err != nil {
return 0, err
}
defer func() {
if f != nil {
if err := f.Close(); err != nil {
level.Error(logger).Log("msg", "close tmp file", "err", err.Error())
}
}
if err := os.RemoveAll(tmp); err != nil {
level.Error(logger).Log("msg", "remove tmp file", "err", err.Error())
}
}()
buf := encoding.Encbuf{B: make([]byte, 3*binary.MaxVarintLen64)}
buf.Reset()
// Write the meta.
buf.PutBE32(MagicTombstone)
n, err := f.Write(buf.Get())
if err != nil {
return 0, err
}
size += n
bytes, err := Encode(tr)
if err != nil {
return 0, errors.Wrap(err, "encoding tombstones")
}
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// Ignore first byte which is the format type. We do this for compatibility.
if _, err := hash.Write(bytes[1:]); err != nil {
return 0, errors.Wrap(err, "calculating hash for tombstones")
}
n, err = f.Write(bytes)
if err != nil {
return 0, errors.Wrap(err, "writing tombstones")
}
size += n
n, err = f.Write(hash.Sum(nil))
if err != nil {
return 0, err
}
size += n
if err := f.Sync(); err != nil {
return 0, tsdb_errors.NewMulti(err, f.Close()).Err()
}
if err = f.Close(); err != nil {
return 0, err
}
f = nil
return int64(size), fileutil.Replace(tmp, path)
}
// Encode encodes the tombstones from the reader.
// It does not attach any magic number or checksum.
func Encode(tr Reader) ([]byte, error) {
buf := encoding.Encbuf{}
buf.PutByte(tombstoneFormatV1)
err := tr.Iter(func(ref uint64, ivs Intervals) error {
for _, iv := range ivs {
buf.PutUvarint64(ref)
buf.PutVarint64(iv.Mint)
buf.PutVarint64(iv.Maxt)
}
return nil
})
return buf.Get(), err
}
// Decode decodes the tombstones from the bytes
// which was encoded using the Encode method.
func Decode(b []byte) (Reader, error) {
d := &encoding.Decbuf{B: b}
if flag := d.Byte(); flag != tombstoneFormatV1 {
return nil, errors.Errorf("invalid tombstone format %x", flag)
}
if d.Err() != nil {
return nil, d.Err()
}
stonesMap := NewMemTombstones()
for d.Len() > 0 {
k := d.Uvarint64()
mint := d.Varint64()
maxt := d.Varint64()
if d.Err() != nil {
return nil, d.Err()
}
stonesMap.AddInterval(k, Interval{mint, maxt})
}
return stonesMap, nil
}
// Stone holds the information on the posting and time-range
// that is deleted.
type Stone struct {
Ref uint64
Intervals Intervals
}
func ReadTombstones(dir string) (Reader, int64, error) {
b, err := ioutil.ReadFile(filepath.Join(dir, TombstonesFilename))
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if os.IsNotExist(err) {
return NewMemTombstones(), 0, nil
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} else if err != nil {
return nil, 0, err
}
if len(b) < tombstonesHeaderSize {
return nil, 0, errors.Wrap(encoding.ErrInvalidSize, "tombstones header")
}
d := &encoding.Decbuf{B: b[:len(b)-4]} // 4 for the checksum.
if mg := d.Be32(); mg != MagicTombstone {
return nil, 0, fmt.Errorf("invalid magic number %x", mg)
}
// Verify checksum.
hash := newCRC32()
// Ignore first byte which is the format type.
if _, err := hash.Write(d.Get()[1:]); err != nil {
return nil, 0, errors.Wrap(err, "write to hash")
}
if binary.BigEndian.Uint32(b[len(b)-4:]) != hash.Sum32() {
return nil, 0, errors.New("checksum did not match")
}
if d.Err() != nil {
return nil, 0, d.Err()
}
stonesMap, err := Decode(d.Get())
if err != nil {
return nil, 0, err
}
return stonesMap, int64(len(b)), nil
}
type MemTombstones struct {
intvlGroups map[uint64]Intervals
mtx sync.RWMutex
}
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// NewMemTombstones creates new in memory Tombstone Reader
// that allows adding new intervals.
func NewMemTombstones() *MemTombstones {
return &MemTombstones{intvlGroups: make(map[uint64]Intervals)}
}
func NewTestMemTombstones(intervals []Intervals) *MemTombstones {
ret := NewMemTombstones()
for i, intervalsGroup := range intervals {
for _, interval := range intervalsGroup {
ret.AddInterval(uint64(i+1), interval)
}
}
return ret
}
func (t *MemTombstones) Get(ref uint64) (Intervals, error) {
t.mtx.RLock()
defer t.mtx.RUnlock()
return t.intvlGroups[ref], nil
}
func (t *MemTombstones) Iter(f func(uint64, Intervals) error) error {
t.mtx.RLock()
defer t.mtx.RUnlock()
for ref, ivs := range t.intvlGroups {
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if err := f(ref, ivs); err != nil {
return err
}
}
return nil
}
func (t *MemTombstones) Total() uint64 {
t.mtx.RLock()
defer t.mtx.RUnlock()
total := uint64(0)
for _, ivs := range t.intvlGroups {
total += uint64(len(ivs))
}
return total
}
// AddInterval to an existing memTombstones.
func (t *MemTombstones) AddInterval(ref uint64, itvs ...Interval) {
t.mtx.Lock()
defer t.mtx.Unlock()
for _, itv := range itvs {
t.intvlGroups[ref] = t.intvlGroups[ref].Add(itv)
}
}
func (*MemTombstones) Close() error {
return nil
}
// Interval represents a single time-interval.
type Interval struct {
Mint, Maxt int64
}
func (tr Interval) InBounds(t int64) bool {
return t >= tr.Mint && t <= tr.Maxt
}
func (tr Interval) IsSubrange(dranges Intervals) bool {
for _, r := range dranges {
if r.InBounds(tr.Mint) && r.InBounds(tr.Maxt) {
return true
}
}
return false
}
// Intervals represents a set of increasing and non-overlapping time-intervals.
type Intervals []Interval
// Add the new time-range to the existing ones.
// The existing ones must be sorted.
func (in Intervals) Add(n Interval) Intervals {
if len(in) == 0 {
return append(in, n)
}
// Find min and max indexes of intervals that overlap with the new interval.
// Intervals are closed [t1, t2] and t is discreet, so if neighbour intervals are 1 step difference
// to the new one, we can merge those together.
mini := sort.Search(len(in), func(i int) bool { return in[i].Maxt >= n.Mint-1 })
if mini == len(in) {
return append(in, n)
}
maxi := sort.Search(len(in)-mini, func(i int) bool { return in[mini+i].Mint > n.Maxt+1 })
if maxi == 0 {
if mini == 0 {
return append(Intervals{n}, in...)
}
return append(in[:mini], append(Intervals{n}, in[mini:]...)...)
}
if n.Mint < in[mini].Mint {
in[mini].Mint = n.Mint
}
in[mini].Maxt = in[maxi+mini-1].Maxt
if n.Maxt > in[mini].Maxt {
in[mini].Maxt = n.Maxt
}
return append(in[:mini+1], in[maxi+mini:]...)
}