break: do not return the Docker Host when retrieving a Docker client

It comes in the TC config

config.go

@@ -44,9 +44,15 @@ More on this: https://golang.testcontainers.org/features/garbage_collector/
 // readConfig reads from testcontainers properties file, if it exists
 // it is possible that certain values get overridden when set as environment variables
 func readConfig() TestcontainersConfig {
-	config := TestcontainersConfig{}
+	config := TestcontainersConfig{
+		Host: "unix:///var/run/docker.sock",
+	}
 
 	applyEnvironmentConfiguration := func(config TestcontainersConfig) TestcontainersConfig {
+		if dockerHostEnv := os.Getenv("DOCKER_HOST"); dockerHostEnv != "" {
+			config.Host = dockerHostEnv
+		}
+
 		ryukDisabledEnv := os.Getenv("TESTCONTAINERS_RYUK_DISABLED")
 		if parseBool(ryukDisabledEnv) {
 			config.RyukDisabled = ryukDisabledEnv == "true"

config_test.go

@@ -18,6 +18,7 @@ func TestReadConfig(t *testing.T) {
 
 		expected := TestcontainersConfig{
 			RyukDisabled: true,
+			Host:         "unix:///var/run/docker.sock",
 		}
 
 		assert.Equal(t, expected, config)
@@ -60,6 +61,18 @@ func TestReadTCConfig(t *testing.T) {
 		assert.Empty(t, config, "TC props file should not exist")
 	})
 
+	t.Run("HOME does not contain TC props file - DOCKER_HOST env is set", func(t *testing.T) {
+		tmpDir := t.TempDir()
+		t.Setenv("HOME", tmpDir)
+		t.Setenv("DOCKER_HOST", "tcp://127.0.0.1:33293")
+
+		config := readConfig()
+		expected := TestcontainersConfig{}
+		expected.Host = "tcp://127.0.0.1:33293"
+
+		assert.Equal(t, expected, config)
+	})
+
 	t.Run("HOME does not contain TC props file - TESTCONTAINERS_ env is set", func(t *testing.T) {
 		tmpDir := t.TempDir()
 		t.Setenv("HOME", tmpDir)

docker.go

@@ -744,10 +744,10 @@ func (p *DockerProvider) SetClient(c client.APIClient) {
 
 var _ ContainerProvider = (*DockerProvider)(nil)
 
-func NewDockerClient() (cli *client.Client, host string, err error) {
+func NewDockerClient() (cli *client.Client, err error) {
 	tcConfig = ReadConfig()
 
-	host = tcConfig.Host
+	host := tcConfig.Host
 
 	opts := []client.Opt{client.FromEnv, client.WithAPIVersionNegotiation()}
 	if host != "" {
@@ -761,10 +761,6 @@ func NewDockerClient() (cli *client.Client, host string, err error) {
 
 			opts = append(opts, client.WithTLSClientConfig(cacertPath, certPath, keyPath))
 		}
-	} else if dockerHostEnv := os.Getenv("DOCKER_HOST"); dockerHostEnv != "" {
-		host = dockerHostEnv
-	} else {
-		host = "unix:///var/run/docker.sock"
 	}
 
 	opts = append(opts, client.WithHTTPHeaders(
@@ -775,20 +771,20 @@ func NewDockerClient() (cli *client.Client, host string, err error) {
 
 	cli, err = client.NewClientWithOpts(opts...)
 	if err != nil {
-		return nil, "", err
+		return nil, err
 	}
 
 	_, err = cli.Ping(context.TODO())
 	if err != nil {
 		// fallback to environment
 		cli, err = testcontainersdocker.NewClient(context.Background())
 		if err != nil {
-			return nil, "", err
+			return nil, err
 		}
 	}
 	defer cli.Close()
 
-	return cli, host, nil
+	return cli, nil
 }
 
 // BuildImage will build and image from context and Dockerfile, then return the tag

docker_test.go

@@ -1393,7 +1393,7 @@ func TestContainerCreationWithBindAndVolume(t *testing.T) {
 	ctx, cnl := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cnl()
 	// Create a Docker client.
-	dockerCli, _, err := NewDockerClient()
+	dockerCli, err := NewDockerClient()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1547,7 +1547,7 @@ func TestContainerCustomPlatformImage(t *testing.T) {
 		require.NoError(t, err)
 		terminateContainerOnEnd(t, ctx, c)
 
-		dockerCli, _, err := NewDockerClient()
+		dockerCli, err := NewDockerClient()
 		require.NoError(t, err)
 
 		ctr, err := dockerCli.ContainerInspect(ctx, c.GetContainerID())
@@ -1584,7 +1584,7 @@ func TestContainerWithCustomHostname(t *testing.T) {
 }
 
 func readHostname(tb testing.TB, containerId string) string {
-	containerClient, _, err := NewDockerClient()
+	containerClient, err := NewDockerClient()
 	if err != nil {
 		tb.Fatalf("Failed to create Docker client: %v", err)
 	}

modules/compose/compose_api.go

@@ -371,7 +371,7 @@ func withEnv(env map[string]string) func(*cli.ProjectOptions) error {
 }
 
 func makeClient(*command.DockerCli) (client.APIClient, error) {
-	dockerClient, _, err := testcontainers.NewDockerClient()
+	dockerClient, err := testcontainers.NewDockerClient()
 	if err != nil {
 		return nil, err
 	}

modules/compose/compose_test.go

@@ -445,7 +445,7 @@ func TestLocalDockerComposeWithVolume(t *testing.T) {
 }
 
 func assertVolumeDoesNotExist(tb testing.TB, volumeName string) {
-	containerClient, _, err := testcontainers.NewDockerClient()
+	containerClient, err := testcontainers.NewDockerClient()
 	if err != nil {
 		tb.Fatalf("Failed to get provider: %v", err)
 	}
@@ -470,7 +470,7 @@ func assertContainerEnvironmentVariables(
 	present map[string]string,
 	absent map[string]string,
 ) {
-	containerClient, _, err := testcontainers.NewDockerClient()
+	containerClient, err := testcontainers.NewDockerClient()
 	if err != nil {
 		tb.Fatalf("Failed to get provider: %v", err)
 	}

provider.go

@@ -128,7 +128,7 @@ func NewDockerProvider(provOpts ...DockerProviderOption) (*DockerProvider, error
 		provOpts[idx].ApplyDockerTo(o)
 	}
 
-	c, host, err := NewDockerClient()
+	c, err := NewDockerClient()
 	if err != nil {
 		return nil, err
 	}
@@ -137,7 +137,7 @@ func NewDockerProvider(provOpts ...DockerProviderOption) (*DockerProvider, error
 
 	p := &DockerProvider{
 		DockerProviderOptions: o,
-		host:                  host,
+		host:                  tcConfig.Host,
 		client:                c,
 		config:                tcConfig,
 	}