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 }