/
backfill.go
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/
backfill.go
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// Copyright 2020 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 main
import (
"context"
"errors"
"fmt"
"io"
"math"
"time"
"github.com/go-kit/log"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/model/textparse"
"github.com/prometheus/prometheus/tsdb"
tsdb_errors "github.com/prometheus/prometheus/tsdb/errors"
)
func getMinAndMaxTimestamps(p textparse.Parser) (int64, int64, error) {
var maxt, mint int64 = math.MinInt64, math.MaxInt64
for {
entry, err := p.Next()
if errors.Is(err, io.EOF) {
break
}
if err != nil {
return 0, 0, fmt.Errorf("next: %w", err)
}
if entry != textparse.EntrySeries {
continue
}
_, ts, _ := p.Series()
if ts == nil {
return 0, 0, fmt.Errorf("expected timestamp for series got none")
}
if *ts > maxt {
maxt = *ts
}
if *ts < mint {
mint = *ts
}
}
if maxt == math.MinInt64 {
maxt = 0
}
if mint == math.MaxInt64 {
mint = 0
}
return maxt, mint, nil
}
func getCompatibleBlockDuration(maxBlockDuration int64) int64 {
blockDuration := tsdb.DefaultBlockDuration
if maxBlockDuration > tsdb.DefaultBlockDuration {
ranges := tsdb.ExponentialBlockRanges(tsdb.DefaultBlockDuration, 10, 3)
idx := len(ranges) - 1 // Use largest range if user asked for something enormous.
for i, v := range ranges {
if v > maxBlockDuration {
idx = i - 1
break
}
}
blockDuration = ranges[idx]
}
return blockDuration
}
func createBlocks(input []byte, mint, maxt, maxBlockDuration int64, maxSamplesInAppender int, outputDir string, humanReadable, quiet bool) (returnErr error) {
blockDuration := getCompatibleBlockDuration(maxBlockDuration)
mint = blockDuration * (mint / blockDuration)
db, err := tsdb.OpenDBReadOnly(outputDir, nil)
if err != nil {
return err
}
defer func() {
returnErr = tsdb_errors.NewMulti(returnErr, db.Close()).Err()
}()
var (
wroteHeader bool
nextSampleTs int64 = math.MaxInt64
)
for t := mint; t <= maxt; t = t + blockDuration {
tsUpper := t + blockDuration
if nextSampleTs != math.MaxInt64 && nextSampleTs >= tsUpper {
// The next sample is not in this timerange, we can avoid parsing
// the file for this timerange.
continue
}
nextSampleTs = math.MaxInt64
err := func() error {
// To prevent races with compaction, a block writer only allows appending samples
// that are at most half a block size older than the most recent sample appended so far.
// However, in the way we use the block writer here, compaction doesn't happen, while we
// also need to append samples throughout the whole block range. To allow that, we
// pretend that the block is twice as large here, but only really add sample in the
// original interval later.
w, err := tsdb.NewBlockWriter(log.NewNopLogger(), outputDir, 2*blockDuration)
if err != nil {
return fmt.Errorf("block writer: %w", err)
}
defer func() {
err = tsdb_errors.NewMulti(err, w.Close()).Err()
}()
ctx := context.Background()
app := w.Appender(ctx)
p := textparse.NewOpenMetricsParser(input)
samplesCount := 0
for {
e, err := p.Next()
if errors.Is(err, io.EOF) {
break
}
if err != nil {
return fmt.Errorf("parse: %w", err)
}
if e != textparse.EntrySeries {
continue
}
_, ts, v := p.Series()
if ts == nil {
l := labels.Labels{}
p.Metric(&l)
return fmt.Errorf("expected timestamp for series %v, got none", l)
}
if *ts < t {
continue
}
if *ts >= tsUpper {
if *ts < nextSampleTs {
nextSampleTs = *ts
}
continue
}
l := labels.Labels{}
p.Metric(&l)
if _, err := app.Append(0, l, *ts, v); err != nil {
return fmt.Errorf("add sample: %w", err)
}
samplesCount++
if samplesCount < maxSamplesInAppender {
continue
}
// If we arrive here, the samples count is greater than the maxSamplesInAppender.
// Therefore the old appender is committed and a new one is created.
// This prevents keeping too many samples lined up in an appender and thus in RAM.
if err := app.Commit(); err != nil {
return fmt.Errorf("commit: %w", err)
}
app = w.Appender(ctx)
samplesCount = 0
}
if err := app.Commit(); err != nil {
return fmt.Errorf("commit: %w", err)
}
block, err := w.Flush(ctx)
switch {
case err == nil:
if quiet {
break
}
blocks, err := db.Blocks()
if err != nil {
return fmt.Errorf("get blocks: %w", err)
}
for _, b := range blocks {
if b.Meta().ULID == block {
printBlocks([]tsdb.BlockReader{b}, !wroteHeader, humanReadable)
wroteHeader = true
break
}
}
case errors.Is(err, tsdb.ErrNoSeriesAppended):
default:
return fmt.Errorf("flush: %w", err)
}
return nil
}()
if err != nil {
return fmt.Errorf("process blocks: %w", err)
}
}
return nil
}
func backfill(maxSamplesInAppender int, input []byte, outputDir string, humanReadable, quiet bool, maxBlockDuration time.Duration) (err error) {
p := textparse.NewOpenMetricsParser(input)
maxt, mint, err := getMinAndMaxTimestamps(p)
if err != nil {
return fmt.Errorf("getting min and max timestamp: %w", err)
}
if err = createBlocks(input, mint, maxt, int64(maxBlockDuration/time.Millisecond), maxSamplesInAppender, outputDir, humanReadable, quiet); err != nil {
return fmt.Errorf("block creation: %w", err)
}
return nil
}