Use random available ports for listening

cmd/ipfs-cluster-service/main.go

@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"net"
 	"os"
 	"os/user"
 	"path/filepath"
@@ -275,7 +274,7 @@ the peer IDs in the given multiaddresses.
 				},
 				cli.BoolFlag{
 					Name:  "randomports",
-					Usage: "listen on random available ports, instead of the default values",
+					Usage: "configure random ports to listen on instead of defaults",
 				},
 			},
 			Action: func(c *cli.Context) error {
@@ -326,7 +325,13 @@ the peer IDs in the given multiaddresses.
 				checkErr("generating default configuration", err)
 				if c.Bool("randomports") {
 					cfgs := cfgHelper.Configs()
-					assignRandomPorts([]*ma.Multiaddr{&cfgs.Cluster.ListenAddr, &cfgs.Restapi.HTTPListenAddr, &cfgs.Ipfsproxy.ListenAddr})
+
+					cfgs.Cluster.ListenAddr, err = cmdutils.RandomizePorts(cfgs.Cluster.ListenAddr)
+					checkErr("randomizing ports", err)
+					cfgs.Restapi.HTTPListenAddr, err = cmdutils.RandomizePorts(cfgs.Restapi.HTTPListenAddr)
+					checkErr("randomizing ports", err)
+					cfgs.Ipfsproxy.ListenAddr, err = cmdutils.RandomizePorts(cfgs.Ipfsproxy.ListenAddr)
+					checkErr("randomizing ports", err)
 				}
 				err = cfgHelper.Manager().ApplyEnvVars()
 				checkErr("applying environment variables to configuration", err)
@@ -641,36 +646,3 @@ func getStateManager() cmdutils.StateManager {
 	checkErr("creating state manager", err)
 	return mgr
 }
-
-func assignRandomPorts(multiAddrs []*ma.Multiaddr) {
-	var prev string
-	for _, m := range multiAddrs {
-		components := []ma.Multiaddr{}
-		ma.ForEach(*m,
-			func(c ma.Component) bool {
-				code := c.Protocol().Code
-				var port int
-				if code == ma.P_TCP || code == ma.P_UDP {
-					ln, err := net.Listen(c.Protocol().Name, prev+":")
-					checkErr("creating a listener", err)
-					defer ln.Close()
-					if code == ma.P_TCP {
-						port = ln.Addr().(*net.TCPAddr).Port
-					} else if code == ma.P_UDP {
-						port = ln.Addr().(*net.UDPAddr).Port
-					}
-					newM, err := ma.NewMultiaddr(fmt.Sprintf("/%s/%d", c.Protocol().Name, port))
-					checkErr("creating multiaddress", err)
-					components = append(components, newM)
-				} else {
-					components = append(components, &c)
-				}
-
-				prev = c.Value()
-
-				return true
-			},
-		)
-		*m = ma.Join(components...)
-	}
-}

cmd/ipfs-cluster-service/main_test.go

@@ -3,14 +3,19 @@ package main
 import (
 	"testing"
 
+	"github.com/ipfs/ipfs-cluster/cmdutils"
+
 	ma "github.com/multiformats/go-multiaddr"
 )
 
 func TestRandomPorts(t *testing.T) {
 	m1, _ := ma.NewMultiaddr("/ip4/0.0.0.0/tcp/9096")
 	m2, _ := ma.NewMultiaddr("/ip4/0.0.0.0/tcp/9096")
 
-	assignRandomPorts([]*ma.Multiaddr{&m1})
+	m1, err := cmdutils.RandomizePorts(m1)
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	v1, err := m1.ValueForProtocol(ma.P_TCP)
 	if err != nil {

cmdutils/cmdutils.go

@@ -1,3 +1,58 @@
 // Package cmdutils contains utilities to facilitate building of command line
 // applications launching cluster peers.
 package cmdutils
+
+import (
+	"fmt"
+	"net"
+
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+// RandomizePorts replaces TCP and UDP ports with random, but valid port
+// values.
+func RandomizePorts(m ma.Multiaddr) (ma.Multiaddr, error) {
+	var prev string
+
+	var err error
+	components := []ma.Multiaddr{}
+	ma.ForEach(m, func(c ma.Component) bool {
+		code := c.Protocol().Code
+
+		if code != ma.P_TCP && code != ma.P_UDP {
+			components = append(components, &c)
+			prev = c.Value()
+			return true
+		}
+
+		var ln net.Listener
+		ln, err = net.Listen(c.Protocol().Name, prev+":")
+		if err != nil {
+			return false
+		}
+		defer ln.Close()
+
+		var c1 *ma.Component
+		c1, err = ma.NewComponent(c.Protocol().Name, fmt.Sprintf("%d", getPort(ln, code)))
+		if err != nil {
+			return false
+		}
+
+		components = append(components, c1)
+		prev = c.Value()
+
+		return true
+	})
+
+	return ma.Join(components...), err
+}
+
+func getPort(ln net.Listener, code int) int {
+	if code == ma.P_TCP {
+		return ln.Addr().(*net.TCPAddr).Port
+	}
+	if code == ma.P_UDP {
+		return ln.Addr().(*net.UDPAddr).Port
+	}
+	return 0
+}