prometheus/tsdb/record/record.go

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// Copyright 2018 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 record
import (
"math"
"sort"
"github.com/pkg/errors"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/tsdb/encoding"
"github.com/prometheus/prometheus/tsdb/tombstones"
)
// Type represents the data type of a record.
type Type uint8
const (
// Invalid is returned for unrecognised WAL record types.
Invalid Type = 255
// Series is used to match WAL records of type Series.
Series Type = 1
// Samples is used to match WAL records of type Samples.
Samples Type = 2
// Tombstones is used to match WAL records of type Tombstones.
Tombstones Type = 3
)
var (
// ErrNotFound is returned if a looked up resource was not found. Duplicate ErrNotFound from head.go.
ErrNotFound = errors.New("not found")
)
// RefSeries is the series labels with the series ID.
type RefSeries struct {
Ref uint64
Labels labels.Labels
}
// RefSample is a timestamp/value pair associated with a reference to a series.
type RefSample struct {
Ref uint64
T int64
V float64
}
// Decoder decodes series, sample, and tombstone records.
// The zero value is ready to use.
type Decoder struct {
}
// Type returns the type of the record.
// Returns RecordInvalid if no valid record type is found.
func (d *Decoder) Type(rec []byte) Type {
if len(rec) < 1 {
return Invalid
}
switch t := Type(rec[0]); t {
case Series, Samples, Tombstones:
return t
}
return Invalid
}
// Series appends series in rec to the given slice.
func (d *Decoder) Series(rec []byte, series []RefSeries) ([]RefSeries, error) {
dec := encoding.Decbuf{B: rec}
if Type(dec.Byte()) != Series {
return nil, errors.New("invalid record type")
}
for len(dec.B) > 0 && dec.Err() == nil {
ref := dec.Be64()
lset := make(labels.Labels, dec.Uvarint())
for i := range lset {
lset[i].Name = dec.UvarintStr()
lset[i].Value = dec.UvarintStr()
}
sort.Sort(lset)
series = append(series, RefSeries{
Ref: ref,
Labels: lset,
})
}
if dec.Err() != nil {
return nil, dec.Err()
}
if len(dec.B) > 0 {
return nil, errors.Errorf("unexpected %d bytes left in entry", len(dec.B))
}
return series, nil
}
// Samples appends samples in rec to the given slice.
func (d *Decoder) Samples(rec []byte, samples []RefSample) ([]RefSample, error) {
dec := encoding.Decbuf{B: rec}
if Type(dec.Byte()) != Samples {
return nil, errors.New("invalid record type")
}
if dec.Len() == 0 {
return samples, nil
}
var (
baseRef = dec.Be64()
baseTime = dec.Be64int64()
)
for len(dec.B) > 0 && dec.Err() == nil {
dref := dec.Varint64()
dtime := dec.Varint64()
val := dec.Be64()
samples = append(samples, RefSample{
Ref: uint64(int64(baseRef) + dref),
T: baseTime + dtime,
V: math.Float64frombits(val),
})
}
if dec.Err() != nil {
return nil, errors.Wrapf(dec.Err(), "decode error after %d samples", len(samples))
}
if len(dec.B) > 0 {
return nil, errors.Errorf("unexpected %d bytes left in entry", len(dec.B))
}
return samples, nil
}
// Tombstones appends tombstones in rec to the given slice.
func (d *Decoder) Tombstones(rec []byte, tstones []tombstones.Stone) ([]tombstones.Stone, error) {
dec := encoding.Decbuf{B: rec}
if Type(dec.Byte()) != Tombstones {
return nil, errors.New("invalid record type")
}
for dec.Len() > 0 && dec.Err() == nil {
tstones = append(tstones, tombstones.Stone{
Ref: dec.Be64(),
Intervals: tombstones.Intervals{
{Mint: dec.Varint64(), Maxt: dec.Varint64()},
},
})
}
if dec.Err() != nil {
return nil, dec.Err()
}
if len(dec.B) > 0 {
return nil, errors.Errorf("unexpected %d bytes left in entry", len(dec.B))
}
return tstones, nil
}
// Encoder encodes series, sample, and tombstones records.
// The zero value is ready to use.
type Encoder struct {
}
// Series appends the encoded series to b and returns the resulting slice.
func (e *Encoder) Series(series []RefSeries, b []byte) []byte {
buf := encoding.Encbuf{B: b}
buf.PutByte(byte(Series))
for _, s := range series {
buf.PutBE64(s.Ref)
buf.PutUvarint(len(s.Labels))
for _, l := range s.Labels {
buf.PutUvarintStr(l.Name)
buf.PutUvarintStr(l.Value)
}
}
return buf.Get()
}
// Samples appends the encoded samples to b and returns the resulting slice.
func (e *Encoder) Samples(samples []RefSample, b []byte) []byte {
buf := encoding.Encbuf{B: b}
buf.PutByte(byte(Samples))
if len(samples) == 0 {
return buf.Get()
}
// Store base timestamp and base reference number of first sample.
// All samples encode their timestamp and ref as delta to those.
first := samples[0]
buf.PutBE64(first.Ref)
buf.PutBE64int64(first.T)
for _, s := range samples {
buf.PutVarint64(int64(s.Ref) - int64(first.Ref))
buf.PutVarint64(s.T - first.T)
buf.PutBE64(math.Float64bits(s.V))
}
return buf.Get()
}
// Tombstones appends the encoded tombstones to b and returns the resulting slice.
func (e *Encoder) Tombstones(tstones []tombstones.Stone, b []byte) []byte {
buf := encoding.Encbuf{B: b}
buf.PutByte(byte(Tombstones))
for _, s := range tstones {
for _, iv := range s.Intervals {
buf.PutBE64(s.Ref)
buf.PutVarint64(iv.Mint)
buf.PutVarint64(iv.Maxt)
}
}
return buf.Get()
}