quic: move the qlog tracer to a separate package

p2p/transport/quic/transport.go

@@ -10,6 +10,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/libp2p/go-libp2p/p2p/transport/quicutils"
+
 	"golang.org/x/crypto/hkdf"
 
 	"github.com/libp2p/go-libp2p/core/connmgr"
@@ -201,7 +203,7 @@ func NewTransport(key ic.PrivKey, psk pnet.PSK, gater connmgr.ConnectionGater, r
 		return nil, err
 	}
 	var tracers []quiclogging.Tracer
-	if qlogTracer != nil {
+	if qlogTracer := quicutils.QLOGTracer; qlogTracer != nil {
 		tracers = append(tracers, qlogTracer)
 	}
 	if cfg.metrics {

p2p/transport/quic/tracer.go → p2p/transport/quicutils/tracer.go

@@ -1,4 +1,4 @@
-package libp2pquic
+package quicutils
 
 import (
 	"bufio"
@@ -7,17 +7,21 @@ import (
 	"os"
 	"time"
 
+	golog "github.com/ipfs/go-log/v2"
 	"github.com/klauspost/compress/zstd"
-
 	"github.com/lucas-clemente/quic-go/logging"
 	"github.com/lucas-clemente/quic-go/qlog"
 )
 
-var qlogTracer logging.Tracer
+var log = golog.Logger("quic-utils")
+
+// QLOGTracer holds a qlog tracer, if qlogging is enabled (enabled using the QLOGDIR environment variable).
+// Otherwise it is nil.
+var QLOGTracer logging.Tracer
 
 func init() {
 	if qlogDir := os.Getenv("QLOGDIR"); len(qlogDir) > 0 {
-		qlogTracer = initQlogger(qlogDir)
+		QLOGTracer = initQlogger(qlogDir)
 	}
 }
 

p2p/transport/quic/tracer_test.go → p2p/transport/quicutils/tracer_test.go

@@ -1,4 +1,4 @@
-package libp2pquic
+package quicutils
 
 import (
 	"bytes"