Ftr: listen on random local port (#29)

* Add: go safely

* Mod: go fmt

* Add: remark and ignoreRecover param

* Add: atomic load var

* directly pass handle func

* Fix: load var in atomic

* Rem: load atomic var by atomic loading

* Add: period param

* Mod: add readme

* Fix: inc value by atomic

* Add: ListenOnTcpRandomPort/ListenOnUdpRandomPort

* Fix: conflict

* Update: readme
Co-authored-by: 望哥 <gelnyang@163.com>
Co-authored-by: yuyu <yuyu.zx@alipay.com>

README.md

@@ -15,6 +15,7 @@ A go sdk for [Apache Dubbo-go](github.com/apache/dubbo-go).
 
 * SlicePool
 > slice pool
+
 ## container
 
 * queue
@@ -27,6 +28,21 @@ A go sdk for [Apache Dubbo-go](github.com/apache/dubbo-go).
 
 * Decimal
 
+## net
+
+* GetLocalIP() (string, error)
+* IsSameAddr(addr1, addr2 net.Addr) bool
+* ListenOnTCPRandomPort(ip string) (*net.TCPListener, error) 
+* ListenOnUDPRandomPort(ip string) (*net.UDPConn, error)
+
+## runtime
+
+* GoSafely 
+> Using `go` in a safe way.
+
+* GoUnterminated
+> Run a goroutine in a safe way whose task is long live as the whole process life time.
+
 ## runtime
 
 * GoSafely 

net/net.go

@@ -38,6 +38,7 @@ func init() {
 	}
 }
 
+// GetLocalIP get local ip
 func GetLocalIP() (string, error) {
 	faces, err := net.Interfaces()
 	if err != nil {
@@ -145,3 +146,32 @@ func IsSameAddr(addr1, addr2 net.Addr) bool {
 	addr2s = strings.TrimPrefix(addr2s, ipv4prefix)
 	return addr1s == addr2s
 }
+
+// ListenOnTCPRandomPort a tcp server listening on a random port by tcp protocol
+func ListenOnTCPRandomPort(ip string) (*net.TCPListener, error) {
+	localAddr := net.TCPAddr{
+		IP:   net.IPv4zero,
+		Port: 0,
+	}
+	if len(ip) > 0 {
+		localAddr.IP = net.ParseIP(ip)
+	}
+
+	// on some containers, u can not bind an random port by the following clause.
+	// listener, err := net.Listen("tcp", ":0")
+
+	return net.ListenTCP("tcp4", &localAddr)
+}
+
+// ListenOnUDPRandomPort a udp endpoint listening on a random port
+func ListenOnUDPRandomPort(ip string) (*net.UDPConn, error) {
+	localAddr := net.UDPAddr{
+		IP:   net.IPv4zero,
+		Port: 0,
+	}
+	if len(ip) > 0 {
+		localAddr.IP = net.ParseIP(ip)
+	}
+
+	return net.ListenUDP("udp4", &localAddr)
+}

net/net_test.go

@@ -19,6 +19,7 @@ package gxnet
 
 import (
 	"net"
+	"strings"
 	"testing"
 )
 
@@ -54,3 +55,35 @@ func TestIsSameAddr(t *testing.T) {
 	addr2.Zone = ""
 	assert.True(t, IsSameAddr(&addr1, &addr1))
 }
+
+func TestListenOnTCPRandomPort(t *testing.T) {
+	l, err := ListenOnTCPRandomPort("")
+	assert.Nil(t, err)
+	t.Logf("a tcp server listen on a random addr:%s", l.Addr())
+	l.Close()
+
+	localIP, err := GetLocalIP()
+	if err == nil {
+		l, err = ListenOnTCPRandomPort(localIP)
+		assert.Nil(t, err)
+		assert.True(t, strings.Contains(l.Addr().String(), localIP))
+		t.Logf("a tcp server listen on a random addr:%s", l.Addr())
+		l.Close()
+	}
+}
+
+func TestListenOnUDPRandomPort(t *testing.T) {
+	l, err := ListenOnUDPRandomPort("")
+	assert.Nil(t, err)
+	t.Logf("a udp peer listen on a random addr:%s", l.LocalAddr())
+	l.Close()
+
+	localIP, err := GetLocalIP()
+	if err == nil {
+		l, err = ListenOnUDPRandomPort(localIP)
+		assert.Nil(t, err)
+		assert.True(t, strings.Contains(l.LocalAddr().String(), localIP))
+		t.Logf("a udp server listen on a random addr:%s", l.LocalAddr())
+		l.Close()
+	}
+}