Fix panic in webseed request rejection logging

Also use a new helper in Logger to simplify things.

client.go

@@ -354,9 +354,7 @@ func (cl *Client) newAnacrolixDhtServer(conn net.PacketConn) (s *dht.Server, err
 		StartingNodes:      cl.config.DhtStartingNodes(conn.LocalAddr().Network()),
 		ConnectionTracking: cl.config.ConnTracker,
 		OnQuery:            cl.config.DHTOnQuery,
-		Logger: cl.logger.WithText(func(m log.Msg) string {
-			return fmt.Sprintf("dht server on %v: %s", conn.LocalAddr().String(), m.Text())
-		}),
+		Logger:             cl.logger.WithContextText(fmt.Sprintf("dht server on %v", conn.LocalAddr().String())),
 	}
 	s, err = dht.NewServer(&cfg)
 	if err == nil {
@@ -1096,9 +1094,7 @@ func (cl *Client) newTorrent(ih metainfo.Hash, specStorage storage.ClientImpl) (
 	}
 	t._pendingPieces.NewSet = priorityBitmapStableNewSet
 	t.requestStrategy = cl.config.DefaultRequestStrategy(t.requestStrategyCallbacks(), &cl._mu)
-	t.logger = cl.logger.WithValues(t).WithText(func(m log.Msg) string {
-		return fmt.Sprintf("%v: %s", t, m.Text())
-	})
+	t.logger = cl.logger.WithContextValue(t)
 	t.setChunkSize(defaultChunkSize)
 	return
 }
@@ -1348,9 +1344,7 @@ func (cl *Client) newConnection(nc net.Conn, outgoing bool, remoteAddr net.Addr,
 		writeBuffer: new(bytes.Buffer),
 	}
 	c.peerImpl = c
-	c.logger = cl.logger.WithValues(c).WithDefaultLevel(log.Debug).WithText(func(m log.Msg) string {
-		return fmt.Sprintf("%v: %s", c, m.Text())
-	})
+	c.logger = cl.logger.WithDefaultLevel(log.Debug).WithContextValue(c)
 	c.writerCond.L = cl.locker()
 	c.setRW(connStatsReadWriter{nc, c})
 	c.r = &rateLimitedReader{

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/anacrolix/dht/v2 v2.6.1-0.20200416071723-3850fa1b802a
 	github.com/anacrolix/envpprof v1.1.0
 	github.com/anacrolix/go-libutp v1.0.2
-	github.com/anacrolix/log v0.7.0
+	github.com/anacrolix/log v0.7.1-0.20200604014615-c244de44fd2d
 	github.com/anacrolix/missinggo v1.2.1
 	github.com/anacrolix/missinggo/perf v1.0.0
 	github.com/anacrolix/missinggo/v2 v2.4.1-0.20200419051441-747d9d7544c6

go.sum

@@ -76,6 +76,8 @@ github.com/anacrolix/log v0.6.1-0.20200416071330-f58a030e6149 h1:3cEyLU9ObAfTnBH
 github.com/anacrolix/log v0.6.1-0.20200416071330-f58a030e6149/go.mod h1:s5yBP/j046fm9odtUTbHOfDUq/zh1W8OkPpJtnX0oQI=
 github.com/anacrolix/log v0.7.0 h1:koGkC/K0LjIbrhLhwfpsfMuvu8nhvY7J4TmLVc1mAwE=
 github.com/anacrolix/log v0.7.0/go.mod h1:s5yBP/j046fm9odtUTbHOfDUq/zh1W8OkPpJtnX0oQI=
+github.com/anacrolix/log v0.7.1-0.20200604014615-c244de44fd2d h1:AkY1QtaxDBPLr1hrxLD8tUL04EPI0asYc2VB8v7Bg2U=
+github.com/anacrolix/log v0.7.1-0.20200604014615-c244de44fd2d/go.mod h1:s5yBP/j046fm9odtUTbHOfDUq/zh1W8OkPpJtnX0oQI=
 github.com/anacrolix/missinggo v0.0.0-20180522035225-b4a5853e62ff/go.mod h1:b0p+7cn+rWMIphK1gDH2hrDuwGOcbB6V4VXeSsEfHVk=
 github.com/anacrolix/missinggo v0.0.0-20180725070939-60ef2fbf63df/go.mod h1:kwGiTUTZ0+p4vAz3VbAI5a30t2YbvemcmspjKwrAz5s=
 github.com/anacrolix/missinggo v0.2.1-0.20190310234110-9fbdc9f242a8 h1:E2Xb2SBsVzHJ1tNMW9QcckYEQcyBKz1ee8qVjeVRWys=

peer-impl.go

@@ -18,4 +18,5 @@ type peerImpl interface {
 	_postCancel(request)
 	onGotInfo(*metainfo.Info)
 	drop()
+	String() string
 }

torrent.go

@@ -2049,6 +2049,7 @@ func (t *Torrent) addWebSeed(url string) {
 		},
 		requests: make(map[request]webseed.Request, maxRequests),
 	}
+	ws.peer.logger = t.logger.WithContextValue(&ws)
 	ws.peer.peerImpl = &ws
 	if t.haveInfo() {
 		ws.onGotInfo(t.info)

web_seed.go

@@ -1,9 +1,9 @@
 package torrent
 
 import (
+	"fmt"
 	"net/http"
 
-	"github.com/anacrolix/log"
 	"github.com/anacrolix/torrent/common"
 	"github.com/anacrolix/torrent/metainfo"
 	pp "github.com/anacrolix/torrent/peer_protocol"
@@ -34,6 +34,10 @@ type webSeed struct {
 
 var _ peerImpl = (*webSeed)(nil)
 
+func (ws *webSeed) String() string {
+	return fmt.Sprintf("webseed peer for %q", ws.client.Url)
+}
+
 func (ws *webSeed) onGotInfo(info *metainfo.Info) {
 	ws.client.FileIndex = segments.NewIndex(common.LengthIterFromUpvertedFiles(info.UpvertedFiles()))
 	ws.client.Info = info
@@ -81,7 +85,7 @@ func (ws *webSeed) requestResultHandler(r request, webseedRequest webseed.Reques
 	ws.peer.t.cl.lock()
 	defer ws.peer.t.cl.unlock()
 	if result.Err != nil {
-		log.Printf("webseed request rejected: %v", result.Err)
+		ws.peer.logger.Printf("request %v rejected: %v", r, result.Err)
 		ws.peer.remoteRejectedRequest(r)
 	} else {
 		err := ws.peer.receiveChunk(&pp.Message{