go1.8: Changes to support golang 1.8 (#4759)

QuirkConn is added to replace net.Conn as a workaround to a golang bug:
https://github.com/golang/go/issues/21133

pkg/http/bufconn.go

@@ -24,7 +24,7 @@ import (
 
 // BufConn - is a generic stream-oriented network connection supporting buffered reader and read/write timeout.
 type BufConn struct {
-	net.Conn
+	QuirkConn
 	bufReader              *bufio.Reader // buffered reader wraps reader in net.Conn.
 	readTimeout            time.Duration // sets the read timeout in the connection.
 	writeTimeout           time.Duration // sets the write timeout in the connection.
@@ -34,7 +34,7 @@ type BufConn struct {
 
 // Sets read timeout
 func (c *BufConn) setReadTimeout() {
-	if c.readTimeout != 0 {
+	if c.readTimeout != 0 && c.canSetReadDeadline() {
 		c.SetReadDeadline(time.Now().UTC().Add(c.readTimeout))
 	}
 }
@@ -91,7 +91,7 @@ func (c *BufConn) Write(b []byte) (n int, err error) {
 func newBufConn(c net.Conn, readTimeout, writeTimeout time.Duration,
 	updateBytesReadFunc, updateBytesWrittenFunc func(int)) *BufConn {
 	return &BufConn{
-		Conn:                   c,
+		QuirkConn:              QuirkConn{Conn: c},
 		bufReader:              bufio.NewReader(c),
 		readTimeout:            readTimeout,
 		writeTimeout:           writeTimeout,

pkg/http/conn_bug_21133.go

@@ -0,0 +1,48 @@
+/*
+ * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package http
+
+import (
+	"net"
+	"sync/atomic"
+	"time"
+)
+
+// QuirkConn - similar to golang net.Conn struct, but contains a workaround of the
+// following the go bug reported here https://github.com/golang/go/issues/21133.
+// Once the bug will be fixed, we can remove this structure and replaces it with
+// the standard net.Conn
+type QuirkConn struct {
+	net.Conn
+	hadReadDeadlineInPast int32 // atomic
+}
+
+// SetReadDeadline - implements a workaround of SetReadDeadline go bug
+func (q *QuirkConn) SetReadDeadline(t time.Time) error {
+	inPast := int32(0)
+	if t.Before(time.Now()) {
+		inPast = 1
+	}
+	atomic.StoreInt32(&q.hadReadDeadlineInPast, inPast)
+	return q.Conn.SetReadDeadline(t)
+}
+
+// canSetReadDeadline - returns if it is safe to set a new
+// read deadline without triggering golang/go#21133 issue.
+func (q *QuirkConn) canSetReadDeadline() bool {
+	return atomic.LoadInt32(&q.hadReadDeadlineInPast) != 1
+}

pkg/http/listener_test.go

@@ -180,9 +180,6 @@ func TestIsHTTPMethod(t *testing.T) {
 
 func TestNewHTTPListener(t *testing.T) {
 	errMsg := ": no such host"
-	if runtime.GOOS == "windows" {
-		errMsg = ": No such host is known."
-	}
 
 	remoteAddrErrMsg := "listen tcp 93.184.216.34:9000: bind: cannot assign requested address"
 	if runtime.GOOS == "windows" {
@@ -204,7 +201,7 @@ func TestNewHTTPListener(t *testing.T) {
 	}{
 		{[]string{"93.184.216.34:9000"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New(remoteAddrErrMsg)},
 		{[]string{"example.org:9000"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New(remoteAddrErrMsg)},
-		{[]string{"unknown-host"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New("listen tcp: missing port in address unknown-host")},
+		{[]string{"unknown-host"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New("listen tcp: address unknown-host: missing port in address")},
 		{[]string{"unknown-host:9000"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New("listen tcp: lookup unknown-host" + errMsg)},
 		{[]string{"localhost:9000", "93.184.216.34:9000"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New(remoteAddrErrMsg)},
 		{[]string{"localhost:9000", "unknown-host:9000"}, nil, time.Duration(0), time.Duration(0), time.Duration(0), nil, nil, nil, errors.New("listen tcp: lookup unknown-host" + errMsg)},