builder/vmware: Randomize HTTP port to avoid collisions

builder/vmware/builder.go

@@ -26,6 +26,8 @@ type config struct {
 	VMName          string   `mapstructure:"vm_name"`
 	OutputDir       string   `mapstructure:"output_directory"`
 	HTTPDir         string   `mapstructure:"http_directory"`
+	HTTPPortMin     uint     `mapstructure:"http_port_min"`
+	HTTPPortMax     uint     `mapstructure:"http_port_max"`
 	BootCommand     []string `mapstructure:"boot_command"`
 	BootWait        time.Duration
 	ShutdownCommand string `mapstructure:"shutdown_command"`
@@ -55,6 +57,14 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 		b.config.VMName = "packer"
 	}
 
+	if b.config.HTTPPortMin == 0 {
+		b.config.HTTPPortMin = 8000
+	}
+
+	if b.config.HTTPPortMax == 0 {
+		b.config.HTTPPortMax = 9000
+	}
+
 	if b.config.VNCPortMin == 0 {
 		b.config.VNCPortMin = 5900
 	}
@@ -70,6 +80,10 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 	// Accumulate any errors
 	errs := make([]error, 0)
 
+	if b.config.HTTPPortMin > b.config.HTTPPortMax {
+		errs = append(errs, errors.New("http_port_min must be less than http_port_max"))
+	}
+
 	if b.config.ISOUrl == "" {
 		errs = append(errs, errors.New("An iso_url must be specified."))
 	}

builder/vmware/builder_test.go

@@ -65,6 +65,34 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_HTTPPort(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Bad
+	config["http_port_min"] = 1000
+	config["http_port_max"] = 500
+	err := b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	// Bad
+	config["http_port_min"] = -500
+	err = b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	// Good
+	config["http_port_min"] = 500
+	config["http_port_max"] = 1000
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+}
+
 func TestBuilderPrepare_ISOUrl(t *testing.T) {
 	var b Builder
 	config := testConfig()

builder/vmware/step_http_server.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
+	"log"
+	"math/rand"
 	"net"
 	"net/http"
 )
@@ -25,27 +27,32 @@ func (s *stepHTTPServer) Run(state map[string]interface{}) multistep.StepAction
 	config := state["config"].(*config)
 	ui := state["ui"].(packer.Ui)
 
-	httpPort := 0
-	if config.HTTPDir != "" {
-		httpPort = 8080
-		httpAddr := fmt.Sprintf(":%d", httpPort)
-
-		ui.Say(fmt.Sprintf("Starting HTTP server on port %d", httpPort))
-
-		// Start the TCP listener
-		var err error
-		s.l, err = net.Listen("tcp", httpAddr)
-		if err != nil {
-			ui.Error(fmt.Sprintf("Error starting HTTP server: %s", err))
-			return multistep.ActionHalt
-		}
-
-		// Start the HTTP server and run it in the background
-		fileServer := http.FileServer(http.Dir(config.HTTPDir))
-		server := &http.Server{Addr: httpAddr, Handler: fileServer}
-		go server.Serve(s.l)
+	var httpPort uint = 0
+	if config.HTTPDir == "" {
+		state["http_port"] = httpPort
 	}
 
+	// Find an available TCP port for our HTTP server
+	var httpAddr string
+	portRange := int(config.HTTPPortMax - config.HTTPPortMin)
+	for {
+		var err error
+		httpPort = uint(rand.Intn(portRange)) + config.HTTPPortMin
+		httpAddr = fmt.Sprintf(":%d", httpPort)
+		log.Printf("Trying port: %d", httpPort)
+		s.l, err = net.Listen("tcp", httpAddr)
+		if err == nil {
+			break
+		}
+	}
+
+	ui.Say(fmt.Sprintf("Starting HTTP server on port %d", httpPort))
+
+	// Start the HTTP server and run it in the background
+	fileServer := http.FileServer(http.Dir(config.HTTPDir))
+	server := &http.Server{Addr: httpAddr, Handler: fileServer}
+	go server.Serve(s.l)
+
 	// Save the address into the state so it can be accessed in the future
 	state["http_port"] = httpPort
 

builder/vmware/step_type_boot_command.go

@@ -19,7 +19,7 @@ const KeyLeftShift uint32 = 0xFFE1
 
 type bootCommandTemplateData struct {
 	HTTPIP   string
-	HTTPPort int
+	HTTPPort uint
 	Name     string
 }
 
@@ -37,7 +37,7 @@ type stepTypeBootCommand struct{}
 
 func (s *stepTypeBootCommand) Run(state map[string]interface{}) multistep.StepAction {
 	config := state["config"].(*config)
-	httpPort := state["http_port"].(int)
+	httpPort := state["http_port"].(uint)
 	ui := state["ui"].(packer.Ui)
 	vncPort := state["vnc_port"].(uint)