AdGuardHome/dnsforward/querylog_file.go

277 lines
5.6 KiB
Go

package dnsforward
import (
"bytes"
"compress/gzip"
"encoding/json"
"fmt"
"os"
"sync"
"time"
"github.com/AdguardTeam/golibs/log"
"github.com/go-test/deep"
)
var (
fileWriteLock sync.Mutex
)
const enableGzip = false
// flushLogBuffer flushes the current buffer to file and resets the current buffer
func (l *queryLog) flushLogBuffer(fullFlush bool) error {
l.fileFlushLock.Lock()
defer l.fileFlushLock.Unlock()
// flush remainder to file
l.logBufferLock.Lock()
needFlush := len(l.logBuffer) >= logBufferCap
if !needFlush && !fullFlush {
l.logBufferLock.Unlock()
return nil
}
flushBuffer := l.logBuffer
l.logBuffer = nil
l.flushPending = false
l.logBufferLock.Unlock()
err := l.flushToFile(flushBuffer)
if err != nil {
log.Error("Saving querylog to file failed: %s", err)
return err
}
return nil
}
// flushToFile saves the specified log entries to the query log file
func (l *queryLog) flushToFile(buffer []*logEntry) error {
if len(buffer) == 0 {
log.Debug("querylog: there's nothing to write to a file")
return nil
}
start := time.Now()
var b bytes.Buffer
e := json.NewEncoder(&b)
for _, entry := range buffer {
err := e.Encode(entry)
if err != nil {
log.Error("Failed to marshal entry: %s", err)
return err
}
}
elapsed := time.Since(start)
log.Debug("%d elements serialized via json in %v: %d kB, %v/entry, %v/entry", len(buffer), elapsed, b.Len()/1024, float64(b.Len())/float64(len(buffer)), elapsed/time.Duration(len(buffer)))
err := checkBuffer(buffer, b)
if err != nil {
log.Error("failed to check buffer: %s", err)
return err
}
var zb bytes.Buffer
filename := l.logFile
// gzip enabled?
if enableGzip {
filename += ".gz"
zw := gzip.NewWriter(&zb)
zw.Name = l.logFile
zw.ModTime = time.Now()
_, err = zw.Write(b.Bytes())
if err != nil {
log.Error("Couldn't compress to gzip: %s", err)
zw.Close()
return err
}
if err = zw.Close(); err != nil {
log.Error("Couldn't close gzip writer: %s", err)
return err
}
} else {
zb = b
}
fileWriteLock.Lock()
defer fileWriteLock.Unlock()
f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
if err != nil {
log.Error("failed to create file \"%s\": %s", filename, err)
return err
}
defer f.Close()
n, err := f.Write(zb.Bytes())
if err != nil {
log.Error("Couldn't write to file: %s", err)
return err
}
log.Debug("ok \"%s\": %v bytes written", filename, n)
return nil
}
func checkBuffer(buffer []*logEntry, b bytes.Buffer) error {
l := len(buffer)
d := json.NewDecoder(&b)
i := 0
for d.More() {
entry := &logEntry{}
err := d.Decode(entry)
if err != nil {
log.Error("Failed to decode: %s", err)
return err
}
if diff := deep.Equal(entry, buffer[i]); diff != nil {
log.Error("decoded buffer differs: %s", diff)
return fmt.Errorf("decoded buffer differs: %s", diff)
}
i++
}
if i != l {
err := fmt.Errorf("check fail: %d vs %d entries", l, i)
log.Error("%v", err)
return err
}
log.Debug("check ok: %d entries", i)
return nil
}
func (l *queryLog) rotateQueryLog() error {
from := l.logFile
to := l.logFile + ".1"
if enableGzip {
from = l.logFile + ".gz"
to = l.logFile + ".gz.1"
}
if _, err := os.Stat(from); os.IsNotExist(err) {
// do nothing, file doesn't exist
return nil
}
err := os.Rename(from, to)
if err != nil {
log.Error("Failed to rename querylog: %s", err)
return err
}
log.Debug("Rotated from %s to %s successfully", from, to)
return nil
}
func (l *queryLog) periodicQueryLogRotate() {
for range time.Tick(queryLogRotationPeriod) {
err := l.rotateQueryLog()
if err != nil {
log.Error("Failed to rotate querylog: %s", err)
// do nothing, continue rotating
}
}
}
func (l *queryLog) genericLoader(onEntry func(entry *logEntry) error, needMore func() bool, timeWindow time.Duration) error {
now := time.Now()
// read from querylog files, try newest file first
var files []string
if enableGzip {
files = []string{
l.logFile + ".gz",
l.logFile + ".gz.1",
}
} else {
files = []string{
l.logFile,
l.logFile + ".1",
}
}
// read from all files
for _, file := range files {
if !needMore() {
break
}
if _, err := os.Stat(file); os.IsNotExist(err) {
// do nothing, file doesn't exist
continue
}
f, err := os.Open(file)
if err != nil {
log.Error("Failed to open file \"%s\": %s", file, err)
// try next file
continue
}
defer f.Close()
var d *json.Decoder
if enableGzip {
zr, err := gzip.NewReader(f)
if err != nil {
log.Error("Failed to create gzip reader: %s", err)
continue
}
defer zr.Close()
d = json.NewDecoder(zr)
} else {
d = json.NewDecoder(f)
}
i := 0
over := 0
max := 10000 * time.Second
var sum time.Duration
// entries on file are in oldest->newest order
// we want maxLen newest
for d.More() {
if !needMore() {
break
}
var entry logEntry
err := d.Decode(&entry)
if err != nil {
log.Error("Failed to decode: %s", err)
// next entry can be fine, try more
continue
}
if now.Sub(entry.Time) > timeWindow {
// log.Tracef("skipping entry") // debug logging
continue
}
if entry.Elapsed > max {
over++
} else {
sum += entry.Elapsed
}
i++
err = onEntry(&entry)
if err != nil {
return err
}
}
elapsed := time.Since(now)
var perunit time.Duration
var avg time.Duration
if i > 0 {
perunit = elapsed / time.Duration(i)
avg = sum / time.Duration(i)
}
log.Debug("file \"%s\": read %d entries in %v, %v/entry, %v over %v, %v avg", file, i, elapsed, perunit, over, max, avg)
}
return nil
}