ceremonyclient/go-libp2p/p2p/transport/quicreuse/tracer.go

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2023-08-21 03:50:38 +00:00
package quicreuse
import (
"bufio"
"fmt"
"io"
"os"
"time"
golog "github.com/ipfs/go-log/v2"
"github.com/klauspost/compress/zstd"
"github.com/quic-go/quic-go"
"github.com/quic-go/quic-go/logging"
"github.com/quic-go/quic-go/qlog"
)
var log = golog.Logger("quic-utils")
// QLOGTracer holds a qlog tracer dir, if qlogging is enabled (enabled using the QLOGDIR environment variable).
// Otherwise it is an empty string.
var qlogTracerDir string
func init() {
qlogTracerDir = os.Getenv("QLOGDIR")
}
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func qloggerForDir(qlogDir string, p logging.Perspective, ci quic.ConnectionID) *logging.ConnectionTracer {
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// create the QLOGDIR, if it doesn't exist
if err := os.MkdirAll(qlogDir, 0777); err != nil {
log.Errorf("creating the QLOGDIR failed: %s", err)
return nil
}
return qlog.NewConnectionTracer(newQlogger(qlogDir, p, ci), p, ci)
}
// The qlogger logs qlog events to a temporary file: .<name>.qlog.swp.
// When it is closed, it compresses the temporary file and saves it as <name>.qlog.zst.
// It is not possible to compress on the fly, as compression algorithms keep a lot of internal state,
// which can easily exhaust the host system's memory when running a few hundred QUIC connections in parallel.
type qlogger struct {
f *os.File // QLOGDIR/.log_xxx.qlog.swp
filename string // QLOGDIR/log_xxx.qlog.zst
*bufio.Writer // buffering the f
}
func newQlogger(qlogDir string, role logging.Perspective, connID quic.ConnectionID) io.WriteCloser {
t := time.Now().UTC().Format("2006-01-02T15-04-05.999999999UTC")
r := "server"
if role == logging.PerspectiveClient {
r = "client"
}
finalFilename := fmt.Sprintf("%s%clog_%s_%s_%s.qlog.zst", qlogDir, os.PathSeparator, t, r, connID)
filename := fmt.Sprintf("%s%c.log_%s_%s_%s.qlog.swp", qlogDir, os.PathSeparator, t, r, connID)
f, err := os.Create(filename)
if err != nil {
log.Errorf("unable to create qlog file %s: %s", filename, err)
return nil
}
return &qlogger{
f: f,
filename: finalFilename,
// The size of a qlog file for a raw file download is ~2/3 of the amount of data transferred.
// bufio.NewWriter creates a buffer with a buffer of only 4 kB, leading to a large number of syscalls.
Writer: bufio.NewWriterSize(f, 128<<10),
}
}
func (l *qlogger) Close() error {
defer os.Remove(l.f.Name())
defer l.f.Close()
if err := l.Writer.Flush(); err != nil {
return err
}
if _, err := l.f.Seek(0, io.SeekStart); err != nil { // set the read position to the beginning of the file
return err
}
f, err := os.Create(l.filename)
if err != nil {
return err
}
defer f.Close()
buf := bufio.NewWriterSize(f, 128<<10)
c, err := zstd.NewWriter(buf, zstd.WithEncoderLevel(zstd.SpeedFastest), zstd.WithWindowSize(32*1024))
if err != nil {
return err
}
if _, err := io.Copy(c, l.f); err != nil {
return err
}
if err := c.Close(); err != nil {
return err
}
return buf.Flush()
}