prometheus/wal/wal_test.go

361 lines
8.4 KiB
Go

// 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 wal
import (
"bytes"
"fmt"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"testing"
"github.com/prometheus/tsdb/testutil"
)
func TestWAL_Repair(t *testing.T) {
for name, test := range map[string]struct {
corrSgm int // Which segment to corrupt.
corrFunc func(f *os.File) // Func that applies the corruption.
intactRecs int // Total expected records left after the repair.
}{
"torn_last_record": {
2,
func(f *os.File) {
_, err := f.Seek(pageSize*2, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{byte(recFirst)})
testutil.Ok(t, err)
},
8,
},
// Ensures that the page buffer is big enough to fit
// an entire page size without panicing.
// https://github.com/prometheus/tsdb/pull/414
"bad_header": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{byte(recPageTerm)})
testutil.Ok(t, err)
},
4,
},
"bad_fragment_sequence": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{byte(recLast)})
testutil.Ok(t, err)
},
4,
},
"bad_fragment_flag": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{123})
testutil.Ok(t, err)
},
4,
},
"bad_checksum": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize+4, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{0})
testutil.Ok(t, err)
},
4,
},
"bad_length": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize+2, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte{0})
testutil.Ok(t, err)
},
4,
},
"bad_content": {
1,
func(f *os.File) {
_, err := f.Seek(pageSize+100, 0)
testutil.Ok(t, err)
_, err = f.Write([]byte("beef"))
testutil.Ok(t, err)
},
4,
},
} {
t.Run(name, func(t *testing.T) {
dir, err := ioutil.TempDir("", "wal_repair")
testutil.Ok(t, err)
defer func() {
testutil.Ok(t, os.RemoveAll(dir))
}()
// We create 3 segments with 3 records each and
// then corrupt a given record in a given segment.
// As a result we want a repaired WAL with given intact records.
segSize := 3 * pageSize
w, err := NewSize(nil, nil, dir, segSize)
testutil.Ok(t, err)
var records [][]byte
for i := 1; i <= 9; i++ {
b := make([]byte, pageSize-recordHeaderSize)
b[0] = byte(i)
records = append(records, b)
testutil.Ok(t, w.Log(b))
}
testutil.Ok(t, w.Close())
f, err := os.OpenFile(SegmentName(dir, test.corrSgm), os.O_RDWR, 0666)
testutil.Ok(t, err)
// Apply corruption function.
test.corrFunc(f)
testutil.Ok(t, f.Close())
w, err = NewSize(nil, nil, dir, segSize)
testutil.Ok(t, err)
defer w.Close()
sr, err := NewSegmentsReader(dir)
testutil.Ok(t, err)
r := NewReader(sr)
for r.Next() {
}
testutil.NotOk(t, r.Err())
testutil.Ok(t, sr.Close())
testutil.Ok(t, w.Repair(r.Err()))
sr, err = NewSegmentsReader(dir)
testutil.Ok(t, err)
defer sr.Close()
r = NewReader(sr)
var result [][]byte
for r.Next() {
var b []byte
result = append(result, append(b, r.Record()...))
}
testutil.Ok(t, r.Err())
testutil.Equals(t, test.intactRecs, len(result), "Wrong number of intact records")
for i, r := range result {
if !bytes.Equal(records[i], r) {
t.Fatalf("record %d diverges: want %x, got %x", i, records[i][:10], r[:10])
}
}
// Make sure the last segment is the corrupt segment.
_, last, err := w.Segments()
testutil.Ok(t, err)
testutil.Equals(t, test.corrSgm, last)
})
}
}
// TestCorruptAndCarryOn writes a multi-segment WAL; corrupts the first segment and
// ensures that an error during reading that segment are correctly repaired before
// moving to write more records to the WAL.
func TestCorruptAndCarryOn(t *testing.T) {
dir, err := ioutil.TempDir("", "wal_repair")
testutil.Ok(t, err)
defer func() {
testutil.Ok(t, os.RemoveAll(dir))
}()
var (
logger = testutil.NewLogger(t)
segmentSize = pageSize * 3
recordSize = (pageSize / 3) - recordHeaderSize
)
// Produce a WAL with a two segments of 3 pages with 3 records each,
// so when we truncate the file we're guaranteed to split a record.
{
w, err := NewSize(logger, nil, dir, segmentSize)
testutil.Ok(t, err)
for i := 0; i < 18; i++ {
buf := make([]byte, recordSize)
_, err := rand.Read(buf)
testutil.Ok(t, err)
err = w.Log(buf)
testutil.Ok(t, err)
}
err = w.Close()
testutil.Ok(t, err)
}
// Check all the segments are the correct size.
{
segments, err := listSegments(dir)
testutil.Ok(t, err)
for _, segment := range segments {
f, err := os.OpenFile(filepath.Join(dir, fmt.Sprintf("%08d", segment.index)), os.O_RDONLY, 0666)
testutil.Ok(t, err)
fi, err := f.Stat()
testutil.Ok(t, err)
t.Log("segment", segment.index, "size", fi.Size())
testutil.Equals(t, int64(segmentSize), fi.Size())
err = f.Close()
testutil.Ok(t, err)
}
}
// Truncate the first file, splitting the middle record in the second
// page in half, leaving 4 valid records.
{
f, err := os.OpenFile(filepath.Join(dir, fmt.Sprintf("%08d", 0)), os.O_RDWR, 0666)
testutil.Ok(t, err)
fi, err := f.Stat()
testutil.Ok(t, err)
testutil.Equals(t, int64(segmentSize), fi.Size())
err = f.Truncate(int64(segmentSize / 2))
testutil.Ok(t, err)
err = f.Close()
testutil.Ok(t, err)
}
// Now try and repair this WAL, and write 5 more records to it.
{
sr, err := NewSegmentsReader(dir)
testutil.Ok(t, err)
reader := NewReader(sr)
i := 0
for ; i < 4 && reader.Next(); i++ {
testutil.Equals(t, recordSize, len(reader.Record()))
}
testutil.Equals(t, 4, i, "not enough records")
testutil.Assert(t, !reader.Next(), "unexpected record")
corruptionErr := reader.Err()
testutil.Assert(t, corruptionErr != nil, "expected error")
err = sr.Close()
testutil.Ok(t, err)
w, err := NewSize(logger, nil, dir, segmentSize)
testutil.Ok(t, err)
err = w.Repair(corruptionErr)
testutil.Ok(t, err)
for i := 0; i < 5; i++ {
buf := make([]byte, recordSize)
_, err := rand.Read(buf)
testutil.Ok(t, err)
err = w.Log(buf)
testutil.Ok(t, err)
}
err = w.Close()
testutil.Ok(t, err)
}
// Replay the WAL. Should get 9 records.
{
sr, err := NewSegmentsReader(dir)
testutil.Ok(t, err)
reader := NewReader(sr)
i := 0
for ; i < 9 && reader.Next(); i++ {
testutil.Equals(t, recordSize, len(reader.Record()))
}
testutil.Equals(t, 9, i, "wrong number of records")
testutil.Assert(t, !reader.Next(), "unexpected record")
testutil.Equals(t, nil, reader.Err())
sr.Close()
}
}
func BenchmarkWAL_LogBatched(b *testing.B) {
dir, err := ioutil.TempDir("", "bench_logbatch")
testutil.Ok(b, err)
defer func() {
testutil.Ok(b, os.RemoveAll(dir))
}()
w, err := New(nil, nil, "testdir")
testutil.Ok(b, err)
defer w.Close()
var buf [2048]byte
var recs [][]byte
b.SetBytes(2048)
for i := 0; i < b.N; i++ {
recs = append(recs, buf[:])
if len(recs) < 1000 {
continue
}
err := w.Log(recs...)
testutil.Ok(b, err)
recs = recs[:0]
}
// Stop timer to not count fsync time on close.
// If it's counted batched vs. single benchmarks are very similar but
// do not show burst throughput well.
b.StopTimer()
}
func BenchmarkWAL_Log(b *testing.B) {
dir, err := ioutil.TempDir("", "bench_logsingle")
testutil.Ok(b, err)
defer func() {
testutil.Ok(b, os.RemoveAll(dir))
}()
w, err := New(nil, nil, "testdir")
testutil.Ok(b, err)
defer w.Close()
var buf [2048]byte
b.SetBytes(2048)
for i := 0; i < b.N; i++ {
err := w.Log(buf[:])
testutil.Ok(b, err)
}
// Stop timer to not count fsync time on close.
// If it's counted batched vs. single benchmarks are very similar but
// do not show burst throughput well.
b.StopTimer()
}