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prometheus/tsdb/tsdbutil/chunks.go

140 lines
3.2 KiB

// 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 tsdbutil
import (
"fmt"
"github.com/prometheus/prometheus/model/histogram"
"github.com/prometheus/prometheus/tsdb/chunkenc"
"github.com/prometheus/prometheus/tsdb/chunks"
)
type Samples interface {
Get(i int) Sample
Len() int
}
type Sample interface {
T() int64
V() float64
H() *histogram.Histogram
FH() *histogram.FloatHistogram
Type() chunkenc.ValueType
}
type SampleSlice []Sample
func (s SampleSlice) Get(i int) Sample { return s[i] }
func (s SampleSlice) Len() int { return len(s) }
// ChunkFromSamples requires all samples to have the same type.
func ChunkFromSamples(s []Sample) chunks.Meta {
return ChunkFromSamplesGeneric(SampleSlice(s))
}
// ChunkFromSamplesGeneric requires all samples to have the same type.
func ChunkFromSamplesGeneric(s Samples) chunks.Meta {
mint, maxt := int64(0), int64(0)
if s.Len() > 0 {
mint, maxt = s.Get(0).T(), s.Get(s.Len()-1).T()
}
if s.Len() == 0 {
return chunks.Meta{
Chunk: chunkenc.NewXORChunk(),
}
}
sampleType := s.Get(0).Type()
c, err := chunkenc.NewEmptyChunk(sampleType.ChunkEncoding())
if err != nil {
panic(err) // TODO(codesome): dont panic.
}
ca, _ := c.Appender()
for i := 0; i < s.Len(); i++ {
switch sampleType {
case chunkenc.ValFloat:
ca.Append(s.Get(i).T(), s.Get(i).V())
case chunkenc.ValHistogram:
ca.AppendHistogram(s.Get(i).T(), s.Get(i).H())
default:
panic(fmt.Sprintf("unknown sample type %s", sampleType.String()))
}
}
return chunks.Meta{
MinTime: mint,
MaxTime: maxt,
Chunk: c,
}
}
type sample struct {
t int64
v float64
h *histogram.Histogram
fh *histogram.FloatHistogram
}
func (s sample) T() int64 {
return s.t
}
func (s sample) V() float64 {
return s.v
}
func (s sample) H() *histogram.Histogram {
return s.h
}
func (s sample) FH() *histogram.FloatHistogram {
return s.fh
}
func (s sample) Type() chunkenc.ValueType {
switch {
case s.h != nil:
return chunkenc.ValHistogram
case s.fh != nil:
return chunkenc.ValFloatHistogram
default:
return chunkenc.ValFloat
}
}
// PopulatedChunk creates a chunk populated with samples every second starting at minTime
func PopulatedChunk(numSamples int, minTime int64) chunks.Meta {
samples := make([]Sample, numSamples)
for i := 0; i < numSamples; i++ {
samples[i] = sample{t: minTime + int64(i*1000), v: 1.0}
}
return ChunkFromSamples(samples)
}
// GenerateSamples starting at start and counting up numSamples.
func GenerateSamples(start, numSamples int) []Sample {
samples := make([]Sample, 0, numSamples)
for i := start; i < start+numSamples; i++ {
samples = append(samples, sample{
t: int64(i),
v: float64(i),
})
}
return samples
}