cmn: GetFreePort (#3255)

libs/common/net.go

@@ -24,3 +24,20 @@ func ProtocolAndAddress(listenAddr string) (string, string) {
 	}
 	return protocol, address
 }
+
+// GetFreePort gets a free port from the operating system.
+// Ripped from https://github.com/phayes/freeport.
+// BSD-licensed.
+func GetFreePort() (int, error) {
+	addr, err := net.ResolveTCPAddr("tcp", "localhost:0")
+	if err != nil {
+		return 0, err
+	}
+
+	l, err := net.ListenTCP("tcp", addr)
+	if err != nil {
+		return 0, err
+	}
+	defer l.Close()
+	return l.Addr().(*net.TCPAddr).Port, nil
+}

p2p/test_util.go

@@ -247,35 +247,25 @@ func testNodeInfo(id ID, name string) NodeInfo {
 }
 
 func testNodeInfoWithNetwork(id ID, name, network string) NodeInfo {
-	port, err := getFreePort()
-	if err != nil {
-		panic(err)
-	}
 	return DefaultNodeInfo{
 		ProtocolVersion: defaultProtocolVersion,
 		ID_:             id,
-		ListenAddr:      fmt.Sprintf("127.0.0.1:%d", port),
+		ListenAddr:      fmt.Sprintf("127.0.0.1:%d", getFreePort()),
 		Network:         network,
 		Version:         "1.2.3-rc0-deadbeef",
 		Channels:        []byte{testCh},
 		Moniker:         name,
 		Other: DefaultNodeInfoOther{
 			TxIndex:    "on",
-			RPCAddress: fmt.Sprintf("127.0.0.1:%d", port),
+			RPCAddress: fmt.Sprintf("127.0.0.1:%d", getFreePort()),
 		},
 	}
 }
 
-func getFreePort() (int, error) {
-	addr, err := net.ResolveTCPAddr("tcp", "localhost:0")
+func getFreePort() int {
+	port, err := cmn.GetFreePort()
 	if err != nil {
-		return 0, err
-	}
-
-	l, err := net.ListenTCP("tcp", addr)
-	if err != nil {
-		return 0, err
+		panic(err)
 	}
-	defer l.Close()
-	return l.Addr().(*net.TCPAddr).Port, nil
+	return port
 }

rpc/test/helpers.go

@@ -11,9 +11,9 @@ import (
 	"github.com/tendermint/tendermint/libs/log"
 
 	abci "github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
 
 	cfg "github.com/tendermint/tendermint/config"
+	cmn "github.com/tendermint/tendermint/libs/common"
 	nm "github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
@@ -64,14 +64,17 @@ func makePathname() string {
 }
 
 func randPort() int {
-	return int(cmn.RandUint16()/2 + 10000)
+	port, err := cmn.GetFreePort()
+	if err != nil {
+		panic(err)
+	}
+	return port
 }
 
 func makeAddrs() (string, string, string) {
-	start := randPort()
-	return fmt.Sprintf("tcp://0.0.0.0:%d", start),
-		fmt.Sprintf("tcp://0.0.0.0:%d", start+1),
-		fmt.Sprintf("tcp://0.0.0.0:%d", start+2)
+	return fmt.Sprintf("tcp://0.0.0.0:%d", randPort()),
+		fmt.Sprintf("tcp://0.0.0.0:%d", randPort()),
+		fmt.Sprintf("tcp://0.0.0.0:%d", randPort())
 }
 
 // GetConfig returns a config for the test cases as a singleton