feat: support customizing the Docker build command (testcontainers#1931)

* break: add BuildOptions method in order to support advanced customisations at build time

* chore: add a test for not finding the given target in the Dockerfile

* chore: make sure the auth configs are always added

* docs: document the advanced usage

* chore: make sure the first tag is not overriden by the user

* chore: make sure the build context and dockerfile is not overriden

* fix: lint

container.go

@@ -65,14 +65,15 @@ type Container interface {
 
 // ImageBuildInfo defines what is needed to build an image
 type ImageBuildInfo interface {
+	BuildOptions() (types.ImageBuildOptions, error) // converts the ImageBuildInfo to a types.ImageBuildOptions
 	GetContext() (io.Reader, error)                 // the path to the build context
 	GetDockerfile() string                          // the relative path to the Dockerfile, including the fileitself
 	GetRepo() string                                // get repo label for image
 	GetTag() string                                 // get tag label for image
 	ShouldPrintBuildLog() bool                      // allow build log to be printed to stdout
 	ShouldBuildImage() bool                         // return true if the image needs to be built
 	GetBuildArgs() map[string]*string               // return the environment args used to build the from Dockerfile
-	GetAuthConfigs() map[string]registry.AuthConfig // return the auth configs to be able to pull from an authenticated docker registry
+	GetAuthConfigs() map[string]registry.AuthConfig // Deprecated. Testcontainers will detect registry credentials automatically. Return the auth configs to be able to pull from an authenticated docker registry
 }
 
 // FromDockerfile represents the parameters needed to build an image from a Dockerfile
@@ -90,6 +91,10 @@ type FromDockerfile struct {
 	// container image. Useful for images that are built from a Dockerfile and take a
 	// long time to build. Keeping the image also Docker to reuse it.
 	KeepImage bool
+	// BuildOptionsModifier Modifier for the build options before image build. Use it for
+	// advanced configurations while building the image. Please consider that the modifier
+	// is called after the default build options are set.
+	BuildOptionsModifier func(*types.ImageBuildOptions)
 }
 
 type ContainerFile struct {
@@ -259,8 +264,14 @@ func (c *ContainerRequest) GetTag() string {
 	return strings.ToLower(t)
 }
 
+// Deprecated: Testcontainers will detect registry credentials automatically, and it will be removed in the next major release
 // GetAuthConfigs returns the auth configs to be able to pull from an authenticated docker registry
 func (c *ContainerRequest) GetAuthConfigs() map[string]registry.AuthConfig {
+	return getAuthConfigsFromDockerfile(c)
+}
+
+// getAuthConfigsFromDockerfile returns the auth configs to be able to pull from an authenticated docker registry
+func getAuthConfigsFromDockerfile(c *ContainerRequest) map[string]registry.AuthConfig {
 	images, err := testcontainersdocker.ExtractImagesFromDockerfile(filepath.Join(c.Context, c.GetDockerfile()), c.GetBuildArgs())
 	if err != nil {
 		return map[string]registry.AuthConfig{}
@@ -291,6 +302,52 @@ func (c *ContainerRequest) ShouldPrintBuildLog() bool {
 	return c.FromDockerfile.PrintBuildLog
 }
 
+// BuildOptions returns the image build options when building a Docker image from a Dockerfile.
+// It will apply some defaults and finally call the BuildOptionsModifier from the FromDockerfile struct,
+// if set.
+func (c *ContainerRequest) BuildOptions() (types.ImageBuildOptions, error) {
+	buildOptions := types.ImageBuildOptions{
+		Remove:      true,
+		ForceRemove: true,
+	}
+
+	if c.FromDockerfile.BuildOptionsModifier != nil {
+		c.FromDockerfile.BuildOptionsModifier(&buildOptions)
+	}
+
+	// apply mandatory values after the modifier
+	buildOptions.BuildArgs = c.GetBuildArgs()
+	buildOptions.Dockerfile = c.GetDockerfile()
+
+	buildContext, err := c.GetContext()
+	if err != nil {
+		return buildOptions, err
+	}
+	buildOptions.Context = buildContext
+
+	// Make sure the auth configs from the Dockerfile are set right after the user-defined build options.
+	authsFromDockerfile := getAuthConfigsFromDockerfile(c)
+
+	if buildOptions.AuthConfigs == nil {
+		buildOptions.AuthConfigs = map[string]registry.AuthConfig{}
+	}
+
+	for registry, authConfig := range authsFromDockerfile {
+		buildOptions.AuthConfigs[registry] = authConfig
+	}
+
+	// make sure the first tag is the one defined in the ContainerRequest
+	tag := fmt.Sprintf("%s:%s", c.GetRepo(), c.GetTag())
+	if len(buildOptions.Tags) > 0 {
+		// prepend the tag
+		buildOptions.Tags = append([]string{tag}, buildOptions.Tags...)
+	} else {
+		buildOptions.Tags = []string{tag}
+	}
+
+	return buildOptions, nil
+}
+
 func (c *ContainerRequest) validateContextAndImage() error {
 	if c.FromDockerfile.Context != "" && c.Image != "" {
 		return errors.New("you cannot specify both an Image and Context in a ContainerRequest")

docker.go

@@ -782,27 +782,14 @@ var _ ContainerProvider = (*DockerProvider)(nil)
 
 // BuildImage will build and image from context and Dockerfile, then return the tag
 func (p *DockerProvider) BuildImage(ctx context.Context, img ImageBuildInfo) (string, error) {
-	repoTag := fmt.Sprintf("%s:%s", img.GetRepo(), img.GetTag())
-
-	buildContext, err := img.GetContext()
-	if err != nil {
-		return "", err
-	}
-
-	buildOptions := types.ImageBuildOptions{
-		BuildArgs:   img.GetBuildArgs(),
-		Dockerfile:  img.GetDockerfile(),
-		AuthConfigs: img.GetAuthConfigs(),
-		Context:     buildContext,
-		Tags:        []string{repoTag},
-		Remove:      true,
-		ForceRemove: true,
-	}
+	buildOptions, err := img.BuildOptions()
 
+	var buildError error
 	var resp types.ImageBuildResponse
 	err = backoff.Retry(func() error {
-		resp, err = p.client.ImageBuild(ctx, buildContext, buildOptions)
+		resp, err = p.client.ImageBuild(ctx, buildOptions.Context, buildOptions)
 		if err != nil {
+			buildError = errors.Join(buildError, err)
 			var enf errdefs.ErrNotFound
 			if errors.As(err, &enf) {
 				return backoff.Permanent(err)
@@ -815,7 +802,7 @@ func (p *DockerProvider) BuildImage(ctx context.Context, img ImageBuildInfo) (st
 		return nil
 	}, backoff.WithContext(backoff.NewExponentialBackOff(), ctx))
 	if err != nil {
-		return "", err
+		return "", errors.Join(buildError, err)
 	}
 
 	if img.ShouldPrintBuildLog() {
@@ -836,7 +823,8 @@ func (p *DockerProvider) BuildImage(ctx context.Context, img ImageBuildInfo) (st
 
 	_ = resp.Body.Close()
 
-	return repoTag, nil
+	// the first tag is the one we want
+	return buildOptions.Tags[0], nil
 }
 
 // CreateContainer fulfills a request for a container without starting it

docs/features/build_from_dockerfile.md

@@ -83,3 +83,14 @@ req := ContainerRequest{
 	},
 }
 ```
+
+## Advanced usage
+
+In the case you need to pass additional arguments to the `docker build` command, you can use the `BuildOptionsModifier` attribute in the `FromDockerfile` struct.
+
+This field holds a function that has access to Docker's ImageBuildOptions type, which is used to build the image. You can use this modifier **on your own risk** to modify the build options with as many options as you need.
+
+<!--codeinclude-->
+[Building From a Dockerfile including build options modifier](../../from_dockerfile_test.go) inside_block:buildFromDockerfileWithModifier
+[Dockerfile including target](../../testdata/target.Dockerfile)
+<!--/codeinclude-->

from_dockerfile_test.go

@@ -2,11 +2,15 @@ package testcontainers
 
 import (
 	"context"
+	"fmt"
+	"io"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/docker/docker/api/types"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestBuildImageFromDockerfile(t *testing.T) {
@@ -116,3 +120,99 @@ func TestBuildImageFromDockerfile_NoTag(t *testing.T) {
 		}
 	})
 }
+
+func TestBuildImageFromDockerfile_Target(t *testing.T) {
+	// there are thre targets: target0, target1 and target2.
+	for i := 0; i < 3; i++ {
+		ctx := context.Background()
+		c, err := GenericContainer(ctx, GenericContainerRequest{
+			ContainerRequest: ContainerRequest{
+				FromDockerfile: FromDockerfile{
+					Context:       "testdata",
+					Dockerfile:    "target.Dockerfile",
+					PrintBuildLog: true,
+					KeepImage:     false,
+					BuildOptionsModifier: func(buildOptions *types.ImageBuildOptions) {
+						buildOptions.Target = fmt.Sprintf("target%d", i)
+					},
+				},
+			},
+			Started: true,
+		})
+		require.NoError(t, err)
+
+		r, err := c.Logs(ctx)
+		require.NoError(t, err)
+
+		logs, err := io.ReadAll(r)
+		require.NoError(t, err)
+
+		assert.Equal(t, fmt.Sprintf("target%d\n\n", i), string(logs))
+
+		t.Cleanup(func() {
+			require.NoError(t, c.Terminate(ctx))
+		})
+	}
+}
+
+func ExampleGenericContainer_buildFromDockerfile() {
+	ctx := context.Background()
+
+	// buildFromDockerfileWithModifier {
+	c, err := GenericContainer(ctx, GenericContainerRequest{
+		ContainerRequest: ContainerRequest{
+			FromDockerfile: FromDockerfile{
+				Context:       "testdata",
+				Dockerfile:    "target.Dockerfile",
+				PrintBuildLog: true,
+				KeepImage:     false,
+				BuildOptionsModifier: func(buildOptions *types.ImageBuildOptions) {
+					buildOptions.Target = "target2"
+				},
+			},
+		},
+		Started: true,
+	})
+	// }
+	if err != nil {
+		panic(err)
+	}
+
+	r, err := c.Logs(ctx)
+	if err != nil {
+		panic(err)
+	}
+
+	logs, err := io.ReadAll(r)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(string(logs))
+
+	// Output: target2
+}
+
+func TestBuildImageFromDockerfile_TargetDoesNotExist(t *testing.T) {
+	// the context cancellation will happen with enough time for the build to fail.
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	_, err := GenericContainer(ctx, GenericContainerRequest{
+		ContainerRequest: ContainerRequest{
+			FromDockerfile: FromDockerfile{
+				Context:       "testdata",
+				Dockerfile:    "target.Dockerfile",
+				PrintBuildLog: true,
+				KeepImage:     false,
+				BuildOptionsModifier: func(buildOptions *types.ImageBuildOptions) {
+					buildOptions.Target = "target-foo"
+				},
+			},
+		},
+		Started: true,
+	})
+	require.Error(t, err)
+
+	assert.Contains(t, err.Error(), "failed to reach build target target-foo in Dockerfile")
+}

testdata/target.Dockerfile

@@ -0,0 +1,8 @@
+FROM docker.io/alpine AS target0
+CMD ["echo", "target0"]
+
+FROM target0 AS target1
+CMD ["echo", "target1"]
+
+FROM target1 AS target2
+CMD ["echo", "target2"]