prometheus/storage/local/persistence.go

598 lines
16 KiB
Go

package local
import (
"bufio"
"encoding/binary"
"fmt"
"io"
"os"
"path"
"github.com/golang/glog"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/prometheus/storage/local/codec"
"github.com/prometheus/prometheus/storage/local/index"
"github.com/prometheus/prometheus/storage/metric"
)
const (
seriesFileName = "series.db"
seriesTempFileName = "series.db.tmp"
headsFileName = "heads.db"
headsFormatVersion = 1
headsMagicString = "PrometheusHeads"
fileBufSize = 1 << 16 // 64kiB. TODO: Tweak.
chunkHeaderLen = 17
chunkHeaderTypeOffset = 0
chunkHeaderFirstTimeOffset = 1
chunkHeaderLastTimeOffset = 9
)
const (
_ = iota
flagChunkDescsLoaded byte = 1 << iota
flagHeadChunkPersisted
)
type diskPersistence struct {
basePath string
chunkLen int
archivedFingerprintToMetrics *index.FingerprintMetricIndex
archivedFingerprintToTimeRange *index.FingerprintTimeRangeIndex
labelPairToFingerprints *index.LabelPairFingerprintIndex
labelNameToLabelValues *index.LabelNameLabelValuesIndex
}
// NewDiskPersistence returns a newly allocated Persistence backed by local disk storage, ready to use.
func NewDiskPersistence(basePath string, chunkLen int) (Persistence, error) {
if err := os.MkdirAll(basePath, 0700); err != nil {
return nil, err
}
dp := &diskPersistence{
basePath: basePath,
chunkLen: chunkLen,
}
var err error
dp.archivedFingerprintToMetrics, err = index.NewFingerprintMetricIndex(basePath)
if err != nil {
return nil, err
}
dp.archivedFingerprintToTimeRange, err = index.NewFingerprintTimeRangeIndex(basePath)
if err != nil {
return nil, err
}
dp.labelPairToFingerprints, err = index.NewLabelPairFingerprintIndex(basePath)
if err != nil {
return nil, err
}
dp.labelNameToLabelValues, err = index.NewLabelNameLabelValuesIndex(basePath)
if err != nil {
return nil, err
}
return dp, nil
}
func (p *diskPersistence) GetFingerprintsForLabelPair(lp metric.LabelPair) (clientmodel.Fingerprints, error) {
fps, _, err := p.labelPairToFingerprints.Lookup(lp)
if err != nil {
return nil, err
}
return fps, nil
}
func (p *diskPersistence) GetLabelValuesForLabelName(ln clientmodel.LabelName) (clientmodel.LabelValues, error) {
lvs, _, err := p.labelNameToLabelValues.Lookup(ln)
if err != nil {
return nil, err
}
return lvs, nil
}
func (p *diskPersistence) GetFingerprintsModifiedBefore(beforeTime clientmodel.Timestamp) ([]clientmodel.Fingerprint, error) {
var fp codec.CodableFingerprint
var tr codec.CodableTimeRange
fps := []clientmodel.Fingerprint{}
p.archivedFingerprintToTimeRange.ForEach(func(kv index.KeyValueAccessor) error {
if err := kv.Value(&tr); err != nil {
return err
}
if tr.First.Before(beforeTime) {
if err := kv.Key(&fp); err != nil {
return err
}
fps = append(fps, clientmodel.Fingerprint(fp))
}
return nil
})
return fps, nil
}
func (p *diskPersistence) PersistChunk(fp clientmodel.Fingerprint, c chunk) error {
// 1. Open chunk file.
f, err := p.openChunkFileForWriting(fp)
if err != nil {
return err
}
defer f.Close()
b := bufio.NewWriterSize(f, chunkHeaderLen+p.chunkLen)
defer b.Flush()
// 2. Write the header (chunk type and first/last times).
err = writeChunkHeader(b, c)
if err != nil {
return err
}
// 3. Write chunk into file.
return c.marshal(b)
}
func (p *diskPersistence) LoadChunks(fp clientmodel.Fingerprint, indexes []int) (chunks, error) {
// TODO: we need to verify at some point that file length is a multiple of
// the chunk size. When is the best time to do this, and where to remember
// it? Right now, we only do it when loading chunkDescs.
f, err := p.openChunkFileForReading(fp)
if err != nil {
return nil, err
}
defer f.Close()
chunks := make(chunks, 0, len(indexes))
defer func() {
if err == nil {
return
}
}()
typeBuf := make([]byte, 1)
for _, idx := range indexes {
_, err := f.Seek(p.offsetForChunkIndex(idx), os.SEEK_SET)
if err != nil {
return nil, err
}
// TODO: check seek offset too?
n, err := f.Read(typeBuf)
if err != nil {
return nil, err
}
if n != 1 {
// Shouldn't happen?
panic("read returned != 1 bytes")
}
_, err = f.Seek(chunkHeaderLen-1, os.SEEK_CUR)
if err != nil {
return nil, err
}
chunk := chunkForType(typeBuf[0])
chunk.unmarshal(f)
chunks = append(chunks, chunk)
}
return chunks, nil
}
func (p *diskPersistence) LoadChunkDescs(fp clientmodel.Fingerprint, beforeTime clientmodel.Timestamp) (chunkDescs, error) {
f, err := p.openChunkFileForReading(fp)
if os.IsNotExist(err) {
return nil, nil
}
if err != nil {
return nil, err
}
defer f.Close()
fi, err := f.Stat()
if err != nil {
return nil, err
}
totalChunkLen := chunkHeaderLen + p.chunkLen
if fi.Size()%int64(totalChunkLen) != 0 {
// TODO: record number of encountered corrupt series files in a metric?
// Truncate the file size to the nearest multiple of chunkLen.
truncateTo := fi.Size() - fi.Size()%int64(totalChunkLen)
glog.Infof("Bad series file size for %s: %d bytes (no multiple of %d). Truncating to %d bytes.", fp, fi.Size(), totalChunkLen, truncateTo)
// TODO: this doesn't work, as this is a read-only file handle.
if err := f.Truncate(truncateTo); err != nil {
return nil, err
}
}
numChunks := int(fi.Size()) / totalChunkLen
cds := make(chunkDescs, 0, numChunks)
for i := 0; i < numChunks; i++ {
_, err := f.Seek(p.offsetForChunkIndex(i)+chunkHeaderFirstTimeOffset, os.SEEK_SET)
if err != nil {
return nil, err
}
chunkTimesBuf := make([]byte, 16)
_, err = io.ReadAtLeast(f, chunkTimesBuf, 16)
if err != nil {
return nil, err
}
cd := &chunkDesc{
firstTimeField: clientmodel.Timestamp(binary.LittleEndian.Uint64(chunkTimesBuf)),
lastTimeField: clientmodel.Timestamp(binary.LittleEndian.Uint64(chunkTimesBuf[8:])),
}
if !cd.firstTime().Before(beforeTime) {
// From here on, we have chunkDescs in memory already.
break
}
cds = append(cds, cd)
}
return cds, nil
}
func (p *diskPersistence) PersistSeriesMapAndHeads(fingerprintToSeries SeriesMap) error {
f, err := os.OpenFile(p.headsPath(), os.O_WRONLY|os.O_TRUNC|os.O_CREATE, 0640)
if err != nil {
return err
}
defer f.Close()
w := bufio.NewWriterSize(f, fileBufSize)
if _, err := w.WriteString(headsMagicString); err != nil {
return err
}
if err := codec.EncodeVarint(w, headsFormatVersion); err != nil {
return err
}
if err := codec.EncodeVarint(w, int64(len(fingerprintToSeries))); err != nil {
return err
}
for fp, series := range fingerprintToSeries {
var seriesFlags byte
if series.chunkDescsLoaded {
seriesFlags |= flagChunkDescsLoaded
}
if series.headChunkPersisted {
seriesFlags |= flagHeadChunkPersisted
}
if err := w.WriteByte(seriesFlags); err != nil {
return err
}
if err := codec.EncodeUint64(w, uint64(fp)); err != nil {
return err
}
buf, err := codec.CodableMetric(series.metric).MarshalBinary()
if err != nil {
return err
}
w.Write(buf)
if err := codec.EncodeVarint(w, int64(len(series.chunkDescs))); err != nil {
return err
}
for i, chunkDesc := range series.chunkDescs {
if series.headChunkPersisted || i < len(series.chunkDescs)-1 {
if err := codec.EncodeVarint(w, int64(chunkDesc.firstTime())); err != nil {
return err
}
if err := codec.EncodeVarint(w, int64(chunkDesc.lastTime())); err != nil {
return err
}
} else {
// This is the non-persisted head chunk. Fully marshal it.
if err := w.WriteByte(chunkType(chunkDesc.chunk)); err != nil {
return err
}
if err := chunkDesc.chunk.marshal(w); err != nil {
return err
}
}
}
}
return w.Flush()
}
func (p *diskPersistence) LoadSeriesMapAndHeads() (SeriesMap, error) {
f, err := os.Open(p.headsPath())
if os.IsNotExist(err) {
return SeriesMap{}, nil
}
if err != nil {
return nil, err
}
defer f.Close()
r := bufio.NewReaderSize(f, fileBufSize)
buf := make([]byte, len(headsMagicString))
if _, err := io.ReadFull(r, buf); err != nil {
return nil, err
}
magic := string(buf)
if magic != headsMagicString {
return nil, fmt.Errorf(
"unexpected magic string, want %q, got %q",
headsMagicString, magic,
)
}
if version, err := binary.ReadVarint(r); version != headsFormatVersion || err != nil {
return nil, fmt.Errorf("unknown heads format version, want %d", headsFormatVersion)
}
numSeries, err := binary.ReadVarint(r)
if err != nil {
return nil, err
}
fingerprintToSeries := make(SeriesMap, numSeries)
for ; numSeries > 0; numSeries-- {
seriesFlags, err := r.ReadByte()
if err != nil {
return nil, err
}
headChunkPersisted := seriesFlags&flagHeadChunkPersisted != 0
fp, err := codec.DecodeUint64(r)
if err != nil {
return nil, err
}
var metric codec.CodableMetric
if err := metric.UnmarshalFromReader(r); err != nil {
return nil, err
}
numChunkDescs, err := binary.ReadVarint(r)
if err != nil {
return nil, err
}
chunkDescs := make(chunkDescs, numChunkDescs)
for i := int64(0); i < numChunkDescs; i++ {
if headChunkPersisted || i < numChunkDescs-1 {
firstTime, err := binary.ReadVarint(r)
if err != nil {
return nil, err
}
lastTime, err := binary.ReadVarint(r)
if err != nil {
return nil, err
}
chunkDescs[i] = &chunkDesc{
firstTimeField: clientmodel.Timestamp(firstTime),
lastTimeField: clientmodel.Timestamp(lastTime),
}
} else {
// Non-persisted head chunk.
chunkType, err := r.ReadByte()
if err != nil {
return nil, err
}
chunk := chunkForType(chunkType)
if err := chunk.unmarshal(r); err != nil {
return nil, err
}
chunkDescs[i] = &chunkDesc{
chunk: chunk,
refCount: 1,
}
}
}
fingerprintToSeries[clientmodel.Fingerprint(fp)] = &memorySeries{
metric: clientmodel.Metric(metric),
chunkDescs: chunkDescs,
chunkDescsLoaded: seriesFlags&flagChunkDescsLoaded != 0,
headChunkPersisted: headChunkPersisted,
}
}
return fingerprintToSeries, nil
}
func (p *diskPersistence) DropChunks(fp clientmodel.Fingerprint, beforeTime clientmodel.Timestamp) (bool, error) {
f, err := p.openChunkFileForReading(fp)
if os.IsNotExist(err) {
return true, nil
}
if err != nil {
return false, err
}
defer f.Close()
// Find the first chunk that should be kept.
for i := 0; ; i++ {
_, err := f.Seek(p.offsetForChunkIndex(i)+chunkHeaderLastTimeOffset, os.SEEK_SET)
if err != nil {
return false, err
}
lastTimeBuf := make([]byte, 8)
_, err = io.ReadAtLeast(f, lastTimeBuf, 8)
if err == io.EOF {
// We ran into the end of the file without finding any chunks that should
// be kept. Remove the whole file.
if err := os.Remove(f.Name()); err != nil {
return true, err
}
return true, nil
}
if err != nil {
return false, err
}
lastTime := clientmodel.Timestamp(binary.LittleEndian.Uint64(lastTimeBuf))
if !lastTime.Before(beforeTime) {
break
}
}
// We've found the first chunk that should be kept. Seek backwards to the
// beginning of its header and start copying everything from there into a new
// file.
_, err = f.Seek(-(chunkHeaderLastTimeOffset + 8), os.SEEK_CUR)
if err != nil {
return false, err
}
dirname := p.dirForFingerprint(fp)
temp, err := os.OpenFile(path.Join(dirname, seriesTempFileName), os.O_WRONLY|os.O_CREATE, 0640)
if err != nil {
return false, err
}
defer temp.Close()
if _, err := io.Copy(temp, f); err != nil {
return false, err
}
os.Rename(path.Join(dirname, seriesTempFileName), path.Join(dirname, seriesFileName))
return false, nil
}
func (p *diskPersistence) IndexMetric(m clientmodel.Metric, fp clientmodel.Fingerprint) error {
// TODO: Don't do it directly, but add it to a queue (which needs to be
// drained before shutdown). Queuing would make this asynchronously, and
// then batches could be created easily.
if err := p.labelNameToLabelValues.Extend(m); err != nil {
return err
}
return p.labelPairToFingerprints.Extend(m, fp)
}
func (p *diskPersistence) UnindexMetric(m clientmodel.Metric, fp clientmodel.Fingerprint) error {
// TODO: Don't do it directly, but add it to a queue (which needs to be
// drained before shutdown). Queuing would make this asynchronously, and
// then batches could be created easily.
labelPairs, err := p.labelPairToFingerprints.Reduce(m, fp)
if err != nil {
return err
}
return p.labelNameToLabelValues.Reduce(labelPairs)
}
func (p *diskPersistence) ArchiveMetric(
// TODO: Two step process, make sure this happens atomically.
fp clientmodel.Fingerprint, m clientmodel.Metric, first, last clientmodel.Timestamp,
) error {
if err := p.archivedFingerprintToMetrics.Put(codec.CodableFingerprint(fp), codec.CodableMetric(m)); err != nil {
return err
}
if err := p.archivedFingerprintToTimeRange.Put(codec.CodableFingerprint(fp), codec.CodableTimeRange{First: first, Last: last}); err != nil {
return err
}
return nil
}
func (p *diskPersistence) HasArchivedMetric(fp clientmodel.Fingerprint) (
hasMetric bool, firstTime, lastTime clientmodel.Timestamp, err error,
) {
firstTime, lastTime, hasMetric, err = p.archivedFingerprintToTimeRange.Lookup(fp)
return
}
func (p *diskPersistence) GetArchivedMetric(fp clientmodel.Fingerprint) (clientmodel.Metric, error) {
metric, _, err := p.archivedFingerprintToMetrics.Lookup(fp)
return metric, err
}
func (p *diskPersistence) DropArchivedMetric(fp clientmodel.Fingerprint) error {
// TODO: Multi-step process, make sure this happens atomically.
metric, err := p.GetArchivedMetric(fp)
if err != nil || metric == nil {
return err
}
if err := p.archivedFingerprintToMetrics.Delete(codec.CodableFingerprint(fp)); err != nil {
return err
}
if err := p.archivedFingerprintToTimeRange.Delete(codec.CodableFingerprint(fp)); err != nil {
return err
}
return p.UnindexMetric(metric, fp)
}
func (p *diskPersistence) UnarchiveMetric(fp clientmodel.Fingerprint) (bool, error) {
// TODO: Multi-step process, make sure this happens atomically.
has, err := p.archivedFingerprintToTimeRange.Has(fp)
if err != nil || !has {
return false, err
}
if err := p.archivedFingerprintToMetrics.Delete(codec.CodableFingerprint(fp)); err != nil {
return false, err
}
if err := p.archivedFingerprintToTimeRange.Delete(codec.CodableFingerprint(fp)); err != nil {
return false, err
}
return true, nil
}
func (p *diskPersistence) Close() error {
var lastError error
if err := p.archivedFingerprintToMetrics.Close(); err != nil {
lastError = err
glog.Error("Error closing archivedFingerprintToMetric index DB: ", err)
}
if err := p.archivedFingerprintToTimeRange.Close(); err != nil {
lastError = err
glog.Error("Error closing archivedFingerprintToTimeRange index DB: ", err)
}
if err := p.labelPairToFingerprints.Close(); err != nil {
lastError = err
glog.Error("Error closing labelPairToFingerprints index DB: ", err)
}
if err := p.labelNameToLabelValues.Close(); err != nil {
lastError = err
glog.Error("Error closing labelNameToLabelValues index DB: ", err)
}
return lastError
}
func (p *diskPersistence) dirForFingerprint(fp clientmodel.Fingerprint) string {
fpStr := fp.String()
return fmt.Sprintf("%s/%c%c/%s", p.basePath, fpStr[0], fpStr[1], fpStr[2:])
}
func (p *diskPersistence) openChunkFileForWriting(fp clientmodel.Fingerprint) (*os.File, error) {
dirname := p.dirForFingerprint(fp)
ex, err := exists(dirname)
if err != nil {
return nil, err
}
if !ex {
if err := os.MkdirAll(dirname, 0700); err != nil {
return nil, err
}
}
return os.OpenFile(path.Join(dirname, seriesFileName), os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0640)
}
func (p *diskPersistence) openChunkFileForReading(fp clientmodel.Fingerprint) (*os.File, error) {
dirname := p.dirForFingerprint(fp)
return os.Open(path.Join(dirname, seriesFileName))
}
func writeChunkHeader(w io.Writer, c chunk) error {
header := make([]byte, chunkHeaderLen)
header[chunkHeaderTypeOffset] = chunkType(c)
binary.LittleEndian.PutUint64(header[chunkHeaderFirstTimeOffset:], uint64(c.firstTime()))
binary.LittleEndian.PutUint64(header[chunkHeaderLastTimeOffset:], uint64(c.lastTime()))
_, err := w.Write(header)
return err
}
func (p *diskPersistence) offsetForChunkIndex(i int) int64 {
return int64(i * (chunkHeaderLen + p.chunkLen))
}
func (p *diskPersistence) headsPath() string {
return path.Join(p.basePath, headsFileName)
}
// exists returns true when the given file or directory exists.
func exists(path string) (bool, error) {
_, err := os.Stat(path)
if err == nil {
return true, nil
}
if os.IsNotExist(err) {
return false, nil
}
return false, err
}