Use random available ports for listening

cmd/ipfs-cluster-service/main.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"os"
 	"os/user"
 	"path/filepath"
@@ -272,6 +273,10 @@ the peer IDs in the given multiaddresses.
 					Name:  "force, f",
 					Usage: "overwrite configuration without prompting",
 				},
+				cli.BoolFlag{
+					Name:  "randomports",
+					Usage: "listen on random available ports, instead of the default values",
+				},
 			},
 			Action: func(c *cli.Context) error {
 				consensus := c.String("consensus")
@@ -319,6 +324,10 @@ the peer IDs in the given multiaddresses.
 				// Generate defaults for all registered components
 				err := cfgHelper.Manager().Default()
 				checkErr("generating default configuration", err)
+				if c.Bool("randomports") {
+					cfgs := cfgHelper.Configs()
+					assignRandomPorts([]*ma.Multiaddr{&cfgs.Cluster.ListenAddr, &cfgs.Restapi.HTTPListenAddr, &cfgs.Ipfsproxy.ListenAddr})
+				}
 				err = cfgHelper.Manager().ApplyEnvVars()
 				checkErr("applying environment variables to configuration", err)
 
@@ -632,3 +641,36 @@ 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

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"testing"
+
+	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})
+
+	v1, err := m1.ValueForProtocol(ma.P_TCP)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	v2, err := m2.ValueForProtocol(ma.P_TCP)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if v1 == v2 {
+		t.Error("expected different ports")
+	}
+}