feat(dsl): have dsl pass port for mock server instead of mock server

In order to be friendly with Docker and Jenkins pipelines by exposing
specified ports the Pact struct will have an optional field for mock
service ports.

The default action is to use the exact same function to find a free
port. But if the field `AllowedMockServicePorts` is passed then it will
limit the ports to those specified

Breaking Changes:
- Changed signature of `daemon.NewService()`. It no longer returns a port as it is
now determined before `daemon.NewService()` is called.
- Changed signature of `client.StartServer()` to accept port. Previously it got the
port from the return of `daemon.NewService()` but the DSL desides the port now

daemon/daemon.go

@@ -99,8 +99,7 @@ func (d Daemon) Shutdown() {
 func (d Daemon) StartServer(request types.MockServer, reply *types.MockServer) error {
 	log.Println("[DEBUG] daemon - starting mock server with args:", request.Args)
 	server := &types.MockServer{}
-	port, svc := d.pactMockSvcManager.NewService(request.Args)
-	server.Port = port
+	svc := d.pactMockSvcManager.NewService(request.Args)
 	server.Status = -1
 	cmd := svc.Start()
 	server.Pid = cmd.Process.Pid
@@ -124,7 +123,7 @@ func (d Daemon) VerifyProvider(request types.VerifyRequest, reply *types.Command
 	}
 
 	var out bytes.Buffer
-	_, svc := d.verificationSvcManager.NewService(request.Args)
+	svc := d.verificationSvcManager.NewService(request.Args)
 	cmd, err := svc.Run(&out)
 
 	if err == nil && cmd.ProcessState != nil && cmd.ProcessState.Success() {

daemon/mock_service.go

@@ -2,11 +2,9 @@ package daemon
 
 import (
 	"fmt"
-	"log"
 	"path/filepath"
 
 	"github.com/kardianos/osext"
-	"github.com/pact-foundation/pact-go/utils"
 )
 
 // MockService is a wrapper for the Pact Mock Service.
@@ -15,19 +13,14 @@ type MockService struct {
 }
 
 // NewService creates a new MockService with default settings.
-func (m *MockService) NewService(args []string) (int, Service) {
-	port, _ := utils.GetFreePort()
-	log.Println("[DEBUG] starting mock service on port:", port)
-
+func (m *MockService) NewService(args []string) Service {
 	m.Args = []string{
 		"service",
-		"--port",
-		fmt.Sprintf("%d", port),
 	}
 	m.Args = append(m.Args, args...)
 
 	m.Command = getMockServiceCommandPath()
-	return port, m
+	return m
 }
 
 func getMockServiceCommandPath() string {

daemon/mock_service_test.go

@@ -4,17 +4,13 @@ import "testing"
 
 func TestMockService_NewService(t *testing.T) {
 	s := &MockService{}
-	port, svc := s.NewService([]string{"--foo"})
-
-	if port <= 0 {
-		t.Fatalf("Expected non-zero port but got: %d", port)
-	}
+	svc := s.NewService([]string{"--foo"})
 
 	if svc == nil {
 		t.Fatalf("Expected a non-nil object but got nil")
 	}
 
-	if s.Args[3] != "--foo" {
+	if s.Args[1] != "--foo" {
 		t.Fatalf("Expected '--foo' argument to be passed")
 	}
 }

daemon/service.go

@@ -13,5 +13,5 @@ type Service interface {
 	List() map[int]*exec.Cmd
 	Start() *exec.Cmd
 	Run(io.Writer) (*exec.Cmd, error)
-	NewService(args []string) (int, Service)
+	NewService(args []string) Service
 }

daemon/service_mock.go

@@ -66,6 +66,6 @@ func (s *ServiceMock) Start() *exec.Cmd {
 }
 
 // NewService creates a new MockService with default settings.
-func (s *ServiceMock) NewService(args []string) (int, Service) {
-	return s.ServicePort, s
+func (s *ServiceMock) NewService(args []string) Service {
+	return s
 }

daemon/verification_service.go

@@ -24,12 +24,12 @@ type VerificationService struct {
 // 		--broker-password
 //    --publish_verification_results
 //    --provider_app_version
-func (m *VerificationService) NewService(args []string) (int, Service) {
+func (m *VerificationService) NewService(args []string) Service {
 	log.Printf("[DEBUG] starting verification service with args: %v\n", args)
 
 	m.Args = args
 	m.Command = getVerifierCommandPath()
-	return -1, m
+	return m
 }
 
 func getVerifierCommandPath() string {

daemon/verification_service_test.go

@@ -4,11 +4,7 @@ import "testing"
 
 func TestVerificationService_NewService(t *testing.T) {
 	s := &VerificationService{}
-	port, svc := s.NewService([]string{"--foo bar"})
-
-	if port != -1 {
-		t.Fatalf("Expected port to be -1 but got: %d", port)
-	}
+	svc := s.NewService([]string{"--foo bar"})
 
 	if svc == nil {
 		t.Fatalf("Expected a non-nil object but got nil")

dsl/client.go

@@ -90,20 +90,22 @@ var waitForPort = func(port int, network string, address string, message string)
 }
 
 // StartServer starts a remote Pact Mock Server.
-func (p *PactClient) StartServer(args []string) *types.MockServer {
+func (p *PactClient) StartServer(args []string, port int) *types.MockServer {
 	log.Println("[DEBUG] client: starting a server")
 	var res types.MockServer
 	client, err := getHTTPClient(p.Port, p.getNetworkInterface(), p.Address)
 	if err == nil {
+		args = append(args, []string{"--port", strconv.Itoa(port)}...)
 		err = client.Call(commandStartServer, types.MockServer{Args: args}, &res)
+		res.Port = port
 		if err != nil {
 			log.Println("[ERROR] rpc:", err.Error())
 		}
 	}
 
 	if err == nil {
-		waitForPort(res.Port, p.getNetworkInterface(), p.Address, fmt.Sprintf(`Timed out waiting for Mock Server to
-			start on port %d - are you sure it's running?`, res.Port))
+		waitForPort(port, p.getNetworkInterface(), p.Address, fmt.Sprintf(`Timed out waiting for Mock Server to
+			start on port %d - are you sure it's running?`, port))
 	}
 
 	return &res

dsl/client_test.go

@@ -130,7 +130,7 @@ func TestClient_List(t *testing.T) {
 func TestClient_ListFail(t *testing.T) {
 	timeoutDuration = 50 * time.Millisecond
 	client := &PactClient{ /* don't supply port */ }
-	client.StartServer([]string{})
+	client.StartServer([]string{}, 0)
 	list := client.ListServers()
 
 	if len(list.Servers) != 0 {
@@ -146,7 +146,8 @@ func TestClient_StartServer(t *testing.T) {
 	defer waitForDaemonToShutdown(port, t)
 	client := &PactClient{Port: port}
 
-	client.StartServer([]string{})
+	mport, _ := utils.GetFreePort()
+	client.StartServer([]string{}, mport)
 	if svc.ServiceStartCount != 1 {
 		t.Fatalf("Expected 1 server to have been started, got %d", svc.ServiceStartCount)
 	}
@@ -189,7 +190,7 @@ func TestClient_RPCErrors(t *testing.T) {
 			return client.StopServer(&types.MockServer{})
 		},
 		&types.MockServer{}: func() interface{} {
-			return client.StartServer([]string{})
+			return client.StartServer([]string{}, 0)
 		},
 		&types.PactListResponse{}: func() interface{} {
 			return client.ListServers()
@@ -297,7 +298,7 @@ func TestClient_StartServerFail(t *testing.T) {
 	timeoutDuration = 50 * time.Millisecond
 
 	client := &PactClient{ /* don't supply port */ }
-	server := client.StartServer([]string{})
+	server := client.StartServer([]string{}, 0)
 	if server.Port != 0 {
 		t.Fatalf("Expected server to be empty %v", server)
 	}

dsl/pact.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/hashicorp/logutils"
 	"github.com/pact-foundation/pact-go/types"
+	"github.com/pact-foundation/pact-go/utils"
 )
 
 // Pact is the container structure to run the Consumer Pact test cases.
@@ -69,6 +70,10 @@ type Pact struct {
 	// Examples include 'tcp', 'tcp4', 'tcp6'
 	// Defaults to 'tcp'
 	Network string
+
+	// Ports MockServer can be deployed to, can be CSV or Range with a dash
+	// Example "1234", "12324,5667", "1234-5667"
+	AllowedMockServerPorts string
 }
 
 // AddInteraction creates a new Pact interaction, initialising all
@@ -114,6 +119,19 @@ func (p *Pact) Setup(startMockServer bool) *Pact {
 		p.pactClient = client
 	}
 
+	// Need to predefine due to scoping
+	var port int
+	var perr error
+	if p.AllowedMockServerPorts != "" {
+		port, perr = utils.FindPortInRange(p.AllowedMockServerPorts)
+	} else {
+		port, perr = utils.GetFreePort()
+	}
+	if perr != nil {
+		log.Println("[ERROR] unable to find free port, mockserver will fail to start")
+	}
+	log.Println("[DEBUG] starting mock service on port:", port)
+
 	if p.Server == nil && startMockServer {
 		args := []string{
 			"--pact-specification-version",
@@ -128,7 +146,7 @@ func (p *Pact) Setup(startMockServer bool) *Pact {
 			p.Provider,
 		}
 
-		p.Server = p.pactClient.StartServer(args)
+		p.Server = p.pactClient.StartServer(args, port)
 	}
 
 	return p

dsl/pact_test.go

@@ -168,6 +168,7 @@ func TestPact_VerifyFail(t *testing.T) {
 }
 
 func TestPact_Setup(t *testing.T) {
+	t.Log("testing pact setup")
 	port, _ := utils.GetFreePort()
 	createDaemon(port, true)
 
@@ -176,17 +177,72 @@ func TestPact_Setup(t *testing.T) {
 	if pact.Server == nil {
 		t.Fatalf("Expected server to be created")
 	}
-
-	pact = &Pact{Port: port, LogLevel: "DEBUG"}
-	pact.Setup(false)
-	if pact.Server != nil {
+	pact2 := &Pact{Port: port, LogLevel: "DEBUG"}
+	pact2.Setup(false)
+	if pact2.Server != nil {
 		t.Fatalf("Expected server to be nil")
 	}
-	if pact.pactClient == nil {
+	if pact2.pactClient == nil {
 		t.Fatalf("Needed to still have a client")
 	}
 }
 
+func TestPact_SetupWithMockServerPort(t *testing.T) {
+	port, _ := utils.GetFreePort()
+	createDaemon(port, true)
+
+	pact := &Pact{Port: port, LogLevel: "DEBUG", AllowedMockServerPorts: "32768"}
+	pact.Setup(true)
+	if pact.Server == nil {
+		t.Fatalf("Expected server to be created")
+	}
+	if pact.Server.Port != 32768 {
+		t.Fatalf("Expected mock daemon to be started on specific port")
+	}
+}
+
+func TestPact_SetupWithMockServerPortCSV(t *testing.T) {
+	port, _ := utils.GetFreePort()
+	createDaemon(port, true)
+
+	pact := &Pact{Port: port, LogLevel: "DEBUG", AllowedMockServerPorts: "32768,32769"}
+	pact.Setup(true)
+	if pact.Server == nil {
+		t.Fatalf("Expected server to be created")
+	}
+	if pact.Server.Port != 32768 {
+		t.Fatalf("Expected mock daemon to be started on specific port")
+	}
+}
+
+func TestPact_SetupWithMockServerPortRange(t *testing.T) {
+	port, _ := utils.GetFreePort()
+	createDaemon(port, true)
+
+	pact := &Pact{Port: port, LogLevel: "DEBUG", AllowedMockServerPorts: "32768-32770"}
+	pact.Setup(true)
+	if pact.Server == nil {
+		t.Fatalf("Expected server to be created")
+	}
+	if pact.Server.Port != 32768 {
+		t.Fatalf("Expected mock daemon to be started on specific port")
+	}
+}
+
+func TestPact_Invalidrange(t *testing.T) {
+	port, _ := utils.GetFreePort()
+	createDaemon(port, true)
+
+	pact := &Pact{Port: port, LogLevel: "DEBUG", AllowedMockServerPorts: "abc-32770"}
+	pact.Setup(true)
+	if pact.Server == nil {
+		t.Fatalf("Expected server to be created")
+	}
+	if pact.Server.Port != 0 {
+		t.Fatalf("Expected mock daemon to be started on specific port")
+	}
+}
+
 func TestPact_Teardown(t *testing.T) {
 	old := waitForPort
 	defer func() { waitForPort = old }()

utils/port.go

@@ -1,7 +1,13 @@
 // Package utils contains a number of helper / utility functions.
 package utils
 
-import "net"
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+)
 
 // GetFreePort Gets an available port by asking the kernal for a random port
 // ready and available for use.
@@ -18,3 +24,64 @@ func GetFreePort() (int, error) {
 	defer l.Close()
 	return l.Addr().(*net.TCPAddr).Port, nil
 }
+
+// FindPortInRange Iterate through CSV or Range of ports to find open port
+// Valid inputs are "8081", "8081,8085", "8081-8085". Do not combine
+// list and range
+func FindPortInRange(s string) (int, error) {
+	// Take care of csv and single value
+	if !strings.Contains(s, "-") {
+		ports := strings.Split(strings.TrimSpace(s), ",")
+		for _, p := range ports {
+			i, err := strconv.Atoi(p)
+			if err != nil {
+				return 0, err
+			}
+			err = checkPort(i)
+			if err != nil {
+				continue
+			}
+			return i, nil
+		}
+		return 0, errors.New("all passed ports are unusable")
+	}
+	// Now take care of ranges
+	ports := strings.Split(strings.TrimSpace(s), "-")
+	if len(ports) != 2 {
+		return 0, errors.New("invalid range passed")
+	}
+	lower, err := strconv.Atoi(ports[0])
+	if err != nil {
+		return 0, err
+	}
+	upper, err := strconv.Atoi(ports[1])
+	if err != nil {
+		return 0, err
+	}
+	if upper < lower {
+		return 0, errors.New("invalid range passed")
+	}
+	for i := lower; i <= upper; i++ {
+		err = checkPort(i)
+		if err != nil {
+			continue
+		}
+		return i, nil
+	}
+	return 0, errors.New("all passed ports are unusable")
+}
+
+func checkPort(p int) error {
+	s := fmt.Sprintf("localhost:%d", p)
+	addr, err := net.ResolveTCPAddr("tcp", s)
+	if err != nil {
+		return err
+	}
+
+	l, err := net.ListenTCP("tcp", addr)
+	if err != nil {
+		return err
+	}
+	defer l.Close()
+	return nil
+}