Remove unnecessary loop around io.CopyBuffer

node/proxy.go

@@ -57,13 +57,13 @@ type wrappedWriter interface {
 // instrumentation.
 func doIcecastProxy(rw http.ResponseWriter, req *http.Request, target *url.URL, streamName string) {
 	log.Printf("proxy: in=%s out=%s stream=%s", req.URL.String(), target.String(), streamName)
+
 	outreq := new(http.Request)
 	*outreq = *req // includes shallow copies of maps, but okay
 
 	// Make a HTTP/1.0 connection to the backend.
 	outreq.URL.Scheme = target.Scheme
 	outreq.URL.Host = target.Host
-	//outreq.URL.Path = singleJoiningSlash(target.Path, req.URL.Path)
 	outreq.URL.Path = target.Path
 	outreq.Proto = "HTTP/1.0"
 	outreq.ProtoMajor = 1
@@ -150,7 +150,7 @@ func doIcecastProxy(rw http.ResponseWriter, req *http.Request, target *url.URL,
 // Copy data between two network connections. On recent Go versions
 // (>1.11), this is quite fast as io.CopyBuffer uses the splice()
 // system call internally (in exchange we lose the ability to figure
-// out which connection is the source of the error).
+// out which end of the connection is the source of the error).
 func copyStream(tag string, out, in *net.TCPConn, promCounter prometheus.Counter, cntr *uint64) {
 	buf := getBuf()
 	defer releaseBuf(buf)
@@ -164,22 +164,13 @@ func copyStream(tag string, out, in *net.TCPConn, promCounter prometheus.Counter
 	defer in.Close()  //nolint
 	defer out.Close() //nolint
 
-	for {
-		n, err := io.CopyBuffer(out, in, buf)
-		promCounter.Add(float64(n))
-		if cntr != nil {
-			atomic.AddUint64(cntr, uint64(n))
-		}
-		if err != nil {
-			if !isCloseError(err) {
-				log.Printf("http: proxy error (%s): %v", tag, err)
-			}
-			return
-		}
-		if n == 0 {
-			log.Printf("http: proxy got 0 bytes from splice()")
-			return
-		}
+	n, err := io.CopyBuffer(out, in, buf)
+	promCounter.Add(float64(n))
+	if cntr != nil {
+		atomic.AddUint64(cntr, uint64(n))
+	}
+	if err != nil && !isCloseError(err) {
+		log.Printf("http: proxy error (%s): %v", tag, err)
 	}
 }
 
@@ -216,8 +207,8 @@ func handleProxy(conn *net.TCPConn, upstream *net.TCPConn, streamName string) {
 // Implementation of a simple buffer cache, to minimize large
 // allocations at runtime.
 const (
-	bufSize     = 8192
-	bufPoolSize = 512
+	bufSize     = 4096
+	bufPoolSize = 128
 )
 
 var bufPool chan []byte