refactor(stacks): use docker-compose-wrapper library (#4979)

api/cmd/portainer/main.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"strings"
 
+	wrapper "github.com/portainer/docker-compose-wrapper"
 	portainer "github.com/portainer/portainer/api"
 	"github.com/portainer/portainer/api/bolt"
 	"github.com/portainer/portainer/api/chisel"
@@ -77,12 +78,17 @@ func initDataStore(dataStorePath string, fileService portainer.FileService) port
 }
 
 func initComposeStackManager(assetsPath string, dataStorePath string, reverseTunnelService portainer.ReverseTunnelService, proxyManager *proxy.Manager) portainer.ComposeStackManager {
-	composeWrapper := exec.NewComposeWrapper(assetsPath, dataStorePath, proxyManager)
+	composeWrapper, err := exec.NewComposeStackManager(assetsPath, dataStorePath, proxyManager)
-	if composeWrapper != nil {
+	if err != nil {
-		return composeWrapper
+		if err == wrapper.ErrBinaryNotFound {
+			log.Printf("[INFO] [message: docker-compose binary not found, falling back to libcompose]")
+			return libcompose.NewComposeStackManager(dataStorePath, reverseTunnelService)
+		}
+
+		log.Fatalf("failed initalizing compose stack manager; err=%s", err)
 	}
 
-	return libcompose.NewComposeStackManager(dataStorePath, reverseTunnelService)
+	return composeWrapper
 }
 
 func initSwarmStackManager(assetsPath string, dataStorePath string, signatureService portainer.DigitalSignatureService, fileService portainer.FileService, reverseTunnelService portainer.ReverseTunnelService) (portainer.SwarmStackManager, error) {

api/exec/compose_stack.go

@@ -0,0 +1,120 @@
+package exec
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"strings"
+
+	wrapper "github.com/portainer/docker-compose-wrapper"
+
+	portainer "github.com/portainer/portainer/api"
+	"github.com/portainer/portainer/api/http/proxy"
+	"github.com/portainer/portainer/api/http/proxy/factory"
+)
+
+// ComposeStackManager is a wrapper for docker-compose binary
+type ComposeStackManager struct {
+	wrapper      *wrapper.ComposeWrapper
+	configPath   string
+	proxyManager *proxy.Manager
+}
+
+// NewComposeStackManager returns a docker-compose wrapper if corresponding binary present, otherwise nil
+func NewComposeStackManager(binaryPath string, configPath string, proxyManager *proxy.Manager) (*ComposeStackManager, error) {
+	wrap, err := wrapper.NewComposeWrapper(binaryPath)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ComposeStackManager{
+		wrapper:      wrap,
+		proxyManager: proxyManager,
+		configPath:   configPath,
+	}, nil
+}
+
+// NormalizeStackName returns a new stack name with unsupported characters replaced
+func (w *ComposeStackManager) NormalizeStackName(name string) string {
+	return name
+}
+
+// ComposeSyntaxMaxVersion returns the maximum supported version of the docker compose syntax
+func (w *ComposeStackManager) ComposeSyntaxMaxVersion() string {
+	return portainer.ComposeSyntaxMaxVersion
+}
+
+// Up builds, (re)creates and starts containers in the background. Wraps `docker-compose up -d` command
+func (w *ComposeStackManager) Up(stack *portainer.Stack, endpoint *portainer.Endpoint) error {
+	url, proxy, err := w.fetchEndpointProxy(endpoint)
+	if err != nil {
+		return err
+	}
+
+	if proxy != nil {
+		defer proxy.Close()
+	}
+
+	envFilePath, err := createEnvFile(stack)
+	if err != nil {
+		return err
+	}
+
+	filePath := stackFilePath(stack)
+
+	_, err = w.wrapper.Up([]string{filePath}, url, stack.Name, envFilePath, w.configPath)
+	return err
+}
+
+// Down stops and removes containers, networks, images, and volumes. Wraps `docker-compose down --remove-orphans` command
+func (w *ComposeStackManager) Down(stack *portainer.Stack, endpoint *portainer.Endpoint) error {
+	url, proxy, err := w.fetchEndpointProxy(endpoint)
+	if err != nil {
+		return err
+	}
+	if proxy != nil {
+		defer proxy.Close()
+	}
+
+	filePath := stackFilePath(stack)
+
+	_, err = w.wrapper.Down([]string{filePath}, url, stack.Name)
+	return err
+}
+
+func stackFilePath(stack *portainer.Stack) string {
+	return path.Join(stack.ProjectPath, stack.EntryPoint)
+}
+
+func (w *ComposeStackManager) fetchEndpointProxy(endpoint *portainer.Endpoint) (string, *factory.ProxyServer, error) {
+	if strings.HasPrefix(endpoint.URL, "unix://") || strings.HasPrefix(endpoint.URL, "npipe://") {
+		return "", nil, nil
+	}
+
+	proxy, err := w.proxyManager.CreateComposeProxyServer(endpoint)
+	if err != nil {
+		return "", nil, err
+	}
+
+	return fmt.Sprintf("http://127.0.0.1:%d", proxy.Port), proxy, nil
+}
+
+func createEnvFile(stack *portainer.Stack) (string, error) {
+	if stack.Env == nil || len(stack.Env) == 0 {
+		return "", nil
+	}
+
+	envFilePath := path.Join(stack.ProjectPath, "stack.env")
+
+	envfile, err := os.OpenFile(envFilePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return "", err
+	}
+
+	for _, v := range stack.Env {
+		envfile.WriteString(fmt.Sprintf("%s=%s\n", v.Name, v.Value))
+	}
+	envfile.Close()
+
+	return envFilePath, nil
+}

api/exec/compose_stack_integration_test.go

@@ -33,7 +33,9 @@ func setup(t *testing.T) (*portainer.Stack, *portainer.Endpoint) {
 		Name:        "project-name",
 	}
 
-	endpoint := &portainer.Endpoint{}
+	endpoint := &portainer.Endpoint{
+		URL: "unix://",
+	}
 
 	return stack, endpoint
 }
@@ -42,14 +44,17 @@ func Test_UpAndDown(t *testing.T) {
 
 	stack, endpoint := setup(t)
 
-	w := NewComposeWrapper("", "", nil)
+	w, err := NewComposeStackManager("", "", nil)
+	if err != nil {
+		t.Fatalf("Failed creating manager: %s", err)
+	}
 
-	err := w.Up(stack, endpoint)
+	err = w.Up(stack, endpoint)
 	if err != nil {
 		t.Fatalf("Error calling docker-compose up: %s", err)
 	}
 
-	if containerExists(composedContainerName) == false {
+	if !containerExists(composedContainerName) {
 		t.Fatal("container should exist")
 	}
 
@@ -63,13 +68,13 @@ func Test_UpAndDown(t *testing.T) {
 	}
 }
 
-func containerExists(contaierName string) bool {
+func containerExists(containerName string) bool {
-	cmd := exec.Command(osProgram("docker"), "ps", "-a", "-f", fmt.Sprintf("name=%s", contaierName))
+	cmd := exec.Command("docker", "ps", "-a", "-f", fmt.Sprintf("name=%s", containerName))
 
 	out, err := cmd.Output()
 	if err != nil {
 		log.Fatalf("failed to list containers: %s", err)
 	}
 
-	return strings.Contains(string(out), contaierName)
+	return strings.Contains(string(out), containerName)
 }

api/exec/compose_stack_test.go

@@ -0,0 +1,112 @@
+package exec
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+
+	portainer "github.com/portainer/portainer/api"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_stackFilePath(t *testing.T) {
+	tests := []struct {
+		name     string
+		stack    *portainer.Stack
+		expected string
+	}{
+		// {
+		// 	name:     "should return empty result if stack is missing",
+		// 	stack:    nil,
+		// 	expected: "",
+		// },
+		// {
+		// 	name:     "should return empty result if stack don't have entrypoint",
+		// 	stack:    &portainer.Stack{},
+		// 	expected: "",
+		// },
+		{
+			name: "should allow file name and dir",
+			stack: &portainer.Stack{
+				ProjectPath: "dir",
+				EntryPoint:  "file",
+			},
+			expected: path.Join("dir", "file"),
+		},
+		{
+			name: "should allow file name only",
+			stack: &portainer.Stack{
+				EntryPoint: "file",
+			},
+			expected: "file",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := stackFilePath(tt.stack)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func Test_createEnvFile(t *testing.T) {
+	dir := t.TempDir()
+
+	tests := []struct {
+		name         string
+		stack        *portainer.Stack
+		expected     string
+		expectedFile bool
+	}{
+		// {
+		// 	name:     "should not add env file option if stack is missing",
+		// 	stack:    nil,
+		// 	expected: "",
+		// },
+		{
+			name: "should not add env file option if stack doesn't have env variables",
+			stack: &portainer.Stack{
+				ProjectPath: dir,
+			},
+			expected: "",
+		},
+		{
+			name: "should not add env file option if stack's env variables are empty",
+			stack: &portainer.Stack{
+				ProjectPath: dir,
+				Env:         []portainer.Pair{},
+			},
+			expected: "",
+		},
+		{
+			name: "should add env file option if stack has env variables",
+			stack: &portainer.Stack{
+				ProjectPath: dir,
+				Env: []portainer.Pair{
+					{Name: "var1", Value: "value1"},
+					{Name: "var2", Value: "value2"},
+				},
+			},
+			expected: "var1=value1\nvar2=value2\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, _ := createEnvFile(tt.stack)
+
+			if tt.expected != "" {
+				assert.Equal(t, path.Join(tt.stack.ProjectPath, "stack.env"), result)
+
+				f, _ := os.Open(path.Join(dir, "stack.env"))
+				content, _ := ioutil.ReadAll(f)
+
+				assert.Equal(t, tt.expected, string(content))
+			} else {
+				assert.Equal(t, "", result)
+			}
+		})
+	}
+}

api/exec/compose_wrapper.go

@@ -1,141 +0,0 @@
-package exec
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"os"
-	"os/exec"
-	"path"
-	"strings"
-
-	portainer "github.com/portainer/portainer/api"
-	"github.com/portainer/portainer/api/http/proxy"
-)
-
-// ComposeWrapper is a wrapper for docker-compose binary
-type ComposeWrapper struct {
-	binaryPath   string
-	dataPath     string
-	proxyManager *proxy.Manager
-}
-
-// NewComposeWrapper returns a docker-compose wrapper if corresponding binary present, otherwise nil
-func NewComposeWrapper(binaryPath, dataPath string, proxyManager *proxy.Manager) *ComposeWrapper {
-	if !IsBinaryPresent(programPath(binaryPath, "docker-compose")) {
-		return nil
-	}
-
-	return &ComposeWrapper{
-		binaryPath:   binaryPath,
-		dataPath:     dataPath,
-		proxyManager: proxyManager,
-	}
-}
-
-// ComposeSyntaxMaxVersion returns the maximum supported version of the docker compose syntax
-func (w *ComposeWrapper) ComposeSyntaxMaxVersion() string {
-	return portainer.ComposeSyntaxMaxVersion
-}
-
-// NormalizeStackName returns a new stack name with unsupported characters replaced
-func (w *ComposeWrapper) NormalizeStackName(name string) string {
-	return name
-}
-
-// Up builds, (re)creates and starts containers in the background. Wraps `docker-compose up -d` command
-func (w *ComposeWrapper) Up(stack *portainer.Stack, endpoint *portainer.Endpoint) error {
-	_, err := w.command([]string{"up", "-d"}, stack, endpoint)
-	return err
-}
-
-// Down stops and removes containers, networks, images, and volumes. Wraps `docker-compose down --remove-orphans` command
-func (w *ComposeWrapper) Down(stack *portainer.Stack, endpoint *portainer.Endpoint) error {
-	_, err := w.command([]string{"down", "--remove-orphans"}, stack, endpoint)
-	return err
-}
-
-func (w *ComposeWrapper) command(command []string, stack *portainer.Stack, endpoint *portainer.Endpoint) ([]byte, error) {
-	if endpoint == nil {
-		return nil, errors.New("cannot call a compose command on an empty endpoint")
-	}
-
-	program := programPath(w.binaryPath, "docker-compose")
-
-	options := setComposeFile(stack)
-
-	options = addProjectNameOption(options, stack)
-	options, err := addEnvFileOption(options, stack)
-	if err != nil {
-		return nil, err
-	}
-
-	if !(endpoint.URL == "" || strings.HasPrefix(endpoint.URL, "unix://") || strings.HasPrefix(endpoint.URL, "npipe://")) {
-
-		proxy, err := w.proxyManager.CreateComposeProxyServer(endpoint)
-		if err != nil {
-			return nil, err
-		}
-
-		defer proxy.Close()
-
-		options = append(options, "-H", fmt.Sprintf("http://127.0.0.1:%d", proxy.Port))
-	}
-
-	args := append(options, command...)
-
-	var stderr bytes.Buffer
-	cmd := exec.Command(program, args...)
-	cmd.Env = os.Environ()
-	cmd.Env = append(cmd.Env, fmt.Sprintf("DOCKER_CONFIG=%s", w.dataPath))
-	cmd.Stderr = &stderr
-
-	out, err := cmd.Output()
-	if err != nil {
-		return out, errors.New(stderr.String())
-	}
-
-	return out, nil
-}
-
-func setComposeFile(stack *portainer.Stack) []string {
-	options := make([]string, 0)
-
-	if stack == nil || stack.EntryPoint == "" {
-		return options
-	}
-
-	composeFilePath := path.Join(stack.ProjectPath, stack.EntryPoint)
-	options = append(options, "-f", composeFilePath)
-	return options
-}
-
-func addProjectNameOption(options []string, stack *portainer.Stack) []string {
-	if stack == nil || stack.Name == "" {
-		return options
-	}
-
-	options = append(options, "-p", stack.Name)
-	return options
-}
-
-func addEnvFileOption(options []string, stack *portainer.Stack) ([]string, error) {
-	if stack == nil || stack.Env == nil || len(stack.Env) == 0 {
-		return options, nil
-	}
-
-	envFilePath := path.Join(stack.ProjectPath, "stack.env")
-
-	envfile, err := os.OpenFile(envFilePath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	if err != nil {
-		return options, err
-	}
-
-	for _, v := range stack.Env {
-		envfile.WriteString(fmt.Sprintf("%s=%s\n", v.Name, v.Value))
-	}
-	envfile.Close()
-
-	options = append(options, "--env-file", envFilePath)
-	return options, nil
-}

api/exec/compose_wrapper_test.go

@@ -1,143 +0,0 @@
-package exec
-
-import (
-	"io/ioutil"
-	"os"
-	"path"
-	"testing"
-
-	portainer "github.com/portainer/portainer/api"
-	"github.com/stretchr/testify/assert"
-)
-
-func Test_setComposeFile(t *testing.T) {
-	tests := []struct {
-		name     string
-		stack    *portainer.Stack
-		expected []string
-	}{
-		{
-			name:     "should return empty result if stack is missing",
-			stack:    nil,
-			expected: []string{},
-		},
-		{
-			name:     "should return empty result if stack don't have entrypoint",
-			stack:    &portainer.Stack{},
-			expected: []string{},
-		},
-		{
-			name: "should allow file name and dir",
-			stack: &portainer.Stack{
-				ProjectPath: "dir",
-				EntryPoint:  "file",
-			},
-			expected: []string{"-f", path.Join("dir", "file")},
-		},
-		{
-			name: "should allow file name only",
-			stack: &portainer.Stack{
-				EntryPoint: "file",
-			},
-			expected: []string{"-f", "file"},
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := setComposeFile(tt.stack)
-			assert.ElementsMatch(t, tt.expected, result)
-		})
-	}
-}
-
-func Test_addProjectNameOption(t *testing.T) {
-	tests := []struct {
-		name     string
-		stack    *portainer.Stack
-		expected []string
-	}{
-		{
-			name:     "should not add project option if stack is missing",
-			stack:    nil,
-			expected: []string{},
-		},
-		{
-			name:     "should not add project option if stack doesn't have name",
-			stack:    &portainer.Stack{},
-			expected: []string{},
-		},
-		{
-			name: "should add project name option if stack has a name",
-			stack: &portainer.Stack{
-				Name: "project-name",
-			},
-			expected: []string{"-p", "project-name"},
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			options := []string{"-a", "b"}
-			result := addProjectNameOption(options, tt.stack)
-			assert.ElementsMatch(t, append(options, tt.expected...), result)
-		})
-	}
-}
-
-func Test_addEnvFileOption(t *testing.T) {
-	dir := t.TempDir()
-
-	tests := []struct {
-		name            string
-		stack           *portainer.Stack
-		expected        []string
-		expectedContent string
-	}{
-		{
-			name:     "should not add env file option if stack is missing",
-			stack:    nil,
-			expected: []string{},
-		},
-		{
-			name:     "should not add env file option if stack doesn't have env variables",
-			stack:    &portainer.Stack{},
-			expected: []string{},
-		},
-		{
-			name: "should not add env file option if stack's env variables are empty",
-			stack: &portainer.Stack{
-				ProjectPath: dir,
-				Env:         []portainer.Pair{},
-			},
-			expected: []string{},
-		},
-		{
-			name: "should add env file option if stack has env variables",
-			stack: &portainer.Stack{
-				ProjectPath: dir,
-				Env: []portainer.Pair{
-					{Name: "var1", Value: "value1"},
-					{Name: "var2", Value: "value2"},
-				},
-			},
-			expected:        []string{"--env-file", path.Join(dir, "stack.env")},
-			expectedContent: "var1=value1\nvar2=value2\n",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			options := []string{"-a", "b"}
-			result, _ := addEnvFileOption(options, tt.stack)
-			assert.ElementsMatch(t, append(options, tt.expected...), result)
-
-			if tt.expectedContent != "" {
-				f, _ := os.Open(path.Join(dir, "stack.env"))
-				content, _ := ioutil.ReadAll(f)
-
-				assert.Equal(t, tt.expectedContent, string(content))
-			}
-		})
-	}
-}

api/exec/utils.go

@@ -1,24 +0,0 @@
-package exec
-
-import (
-	"os/exec"
-	"path/filepath"
-	"runtime"
-)
-
-func osProgram(program string) string {
-	if runtime.GOOS == "windows" {
-		program += ".exe"
-	}
-	return program
-}
-
-func programPath(rootPath, program string) string {
-	return filepath.Join(rootPath, osProgram(program))
-}
-
-// IsBinaryPresent returns true if corresponding program exists on PATH
-func IsBinaryPresent(program string) bool {
-	_, err := exec.LookPath(program)
-	return err == nil
-}

api/exec/utils_test.go

@@ -1,16 +0,0 @@
-package exec
-
-import (
-	"testing"
-)
-
-func Test_isBinaryPresent(t *testing.T) {
-
-	if !IsBinaryPresent("docker") {
-		t.Error("expect docker binary to exist on the path")
-	}
-
-	if IsBinaryPresent("executable-with-this-name-should-not-exist") {
-		t.Error("expect binary with a random name to be missing on the path")
-	}
-}

api/go.mod

@@ -27,10 +27,11 @@ require (
 	github.com/mitchellh/mapstructure v1.1.2 // indirect
 	github.com/orcaman/concurrent-map v0.0.0-20190826125027-8c72a8bb44f6
 	github.com/pkg/errors v0.9.1
+	github.com/portainer/docker-compose-wrapper v0.0.0-20210527221011-0a1418224b92
 	github.com/portainer/libcompose v0.5.3
 	github.com/portainer/libcrypto v0.0.0-20190723020515-23ebe86ab2c2
 	github.com/portainer/libhttp v0.0.0-20190806161843-ba068f58be33
-	github.com/stretchr/testify v1.6.1
+	github.com/stretchr/testify v1.7.0
 	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2
 	golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6

api/go.sum

@@ -242,6 +242,8 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/portainer/docker-compose-wrapper v0.0.0-20210527221011-0a1418224b92 h1:Hh7SHCf3SJblVywU0TTn5lpTKsH5W23LAKH5sqWggig=
+github.com/portainer/docker-compose-wrapper v0.0.0-20210527221011-0a1418224b92/go.mod h1:PF2O2O4UNYWdtPcp6n/mIKpKk+f1jhFTezS8txbf+XM=
 github.com/portainer/libcompose v0.5.3 h1:tE4WcPuGvo+NKeDkDWpwNavNLZ5GHIJ4RvuZXsI9uI8=
 github.com/portainer/libcompose v0.5.3/go.mod h1:7SKd/ho69rRKHDFSDUwkbMcol2TMKU5OslDsajr8Ro8=
 github.com/portainer/libcrypto v0.0.0-20190723020515-23ebe86ab2c2 h1:0PfgGLys9yHr4rtnirg0W0Cjvv6/DzxBIZk5sV59208=
@@ -277,8 +279,8 @@ github.com/stretchr/testify v0.0.0-20151208002404-e3a8ff8ce365/go.mod h1:a8OnRci
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce h1:fb190+cK2Xz/dvi9Hv8eCYJYvIGUTN2/KLq1pT6CjEc=
 github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce/go.mod h1:o8v6yHRoik09Xen7gje4m9ERNah1d1PPsVq1VEx9vE4=
 github.com/urfave/cli v1.21.0/go.mod h1:lxDj6qX9Q6lWQxIrbrT0nwecwUtRnhVZAJjJZrVUZZQ=

api/http/proxy/factory/docker_compose.go

@@ -49,13 +49,18 @@ func (factory *ProxyFactory) NewDockerComposeAgentProxy(endpoint *portainer.Endp
 	proxy.Transport = dockercompose.NewAgentTransport(factory.signatureService, httpTransport)
 
 	proxyServer := &ProxyServer{
-		&http.Server{
+		server: &http.Server{
 			Handler: proxy,
 		},
-		0,
+		Port: 0,
 	}
 
-	return proxyServer, proxyServer.start()
+	err = proxyServer.start()
+	if err != nil {
+		return nil, err
+	}
+
+	return proxyServer, err
 }
 
 func (proxy *ProxyServer) start() error {
@@ -72,7 +77,7 @@ func (proxy *ProxyServer) start() error {
 		err := proxy.server.Serve(listener)
 		log.Printf("Exiting Proxy server %s\n", proxyHost)
 
-		if err != http.ErrServerClosed {
+		if err != nil && err != http.ErrServerClosed {
 			log.Printf("Proxy server %s exited with an error: %s\n", proxyHost, err)
 		}
 	}()