feat: Implement basic build & push capabilities for services (#68)

* wip: Build experiments

* wip: overall structure for build/push

* ref: Split method, add test fixture

* feat: Basic push functionality

* ref: Better structure and output

* feat: Handle registry auth

* feat: Integrate with deploy

* ref: Split into files

* fix: Modernize push options

internal/cli/build.go

@@ -0,0 +1,197 @@
+package cli
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+
+	composetypes "github.com/compose-spec/compose-go/v2/types"
+	"github.com/distribution/reference"
+	"github.com/docker/cli/cli/config"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/image"
+	dockerclient "github.com/docker/docker/client"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/registry"
+)
+
+type BuildOptions struct {
+	Files    []string
+	Profiles []string
+	Services []string
+	Push     bool
+	NoCache  bool
+}
+
+// GetServicesThatNeedBuild returns a map of services that require building
+func GetServicesThatNeedBuild(project *composetypes.Project) map[string]composetypes.ServiceConfig {
+	servicesToBuild := make(map[string]composetypes.ServiceConfig, len(project.Services))
+	for serviceName, service := range project.Services {
+		if service.Build == nil {
+			continue
+		}
+		servicesToBuild[serviceName] = service
+	}
+	return servicesToBuild
+}
+
+// BuildServices builds the services defined in the provided map.
+func BuildServices(ctx context.Context, servicesToBuild map[string]composetypes.ServiceConfig, opts BuildOptions) error {
+	fmt.Println("Building services...")
+
+	// Init docker client (can be local or remote, depending on DOCKER_HOST environment variable)
+	dockerCli, err := dockerclient.NewClientWithOpts(dockerclient.FromEnv, dockerclient.WithAPIVersionNegotiation())
+	if err != nil {
+		return err
+	}
+	defer dockerCli.Close()
+
+	serviceImages := make(map[string]string, len(servicesToBuild))
+
+	// Build the services using the local docker client and compose libraries
+	for _, service := range servicesToBuild {
+		fmt.Printf("Building service: %s\n", service.Name)
+		imageName, err := buildSingleService(ctx, dockerCli, service, opts)
+		if err != nil {
+			return fmt.Errorf("build service %s: %w", service.Name, err)
+		}
+		serviceImages[service.Name] = imageName
+	}
+	fmt.Printf("Service images are built.\n")
+
+	if opts.Push {
+		err = pushServiceImages(ctx, dockerCli, serviceImages)
+	}
+
+	return err
+}
+
+// buildSingleService builds a single service using the Docker client and Compose libraries.
+func buildSingleService(ctx context.Context, dockerCli *dockerclient.Client, service composetypes.ServiceConfig, opts BuildOptions) (string, error) {
+	if service.Build == nil {
+		return "", fmt.Errorf("service %s has no build configuration", service.Name)
+	}
+	if service.Image == "" {
+		return "", fmt.Errorf("service %s has no image specified; building services without image is not supported yet", service.Name)
+	}
+
+	buildContextPath := service.Build.Context
+	imageName := service.Image
+
+	// Create a tar archive of the build context
+	buildContext, err := archive.TarWithOptions(buildContextPath, &archive.TarOptions{})
+	if err != nil {
+		return "", fmt.Errorf("failed to create build context for service %s: %w", service.Name, err)
+	}
+
+	buildOptions := types.ImageBuildOptions{
+		// TODO: Support Dockerfiles outside the build context
+		// See https://github.com/docker/compose/blob/cf89fd1aa1328d5af77658ccc5a1e1b29981ae80/pkg/compose/build_classic.go#L92
+		Dockerfile: service.Build.Dockerfile,
+		Tags:       []string{imageName},
+		Remove:     true, // Remove intermediate containers
+		NoCache:    opts.NoCache,
+	}
+
+	buildResponse, err := dockerCli.ImageBuild(ctx, buildContext, buildOptions)
+	if err != nil {
+		return "", fmt.Errorf("failed to build image for service %s: %w", service.Name, err)
+	}
+	defer buildResponse.Body.Close()
+
+	// Print the build output
+	decoder := json.NewDecoder(buildResponse.Body)
+	for {
+		var message map[string]interface{}
+		if err := decoder.Decode(&message); err == io.EOF {
+			break
+		} else if err != nil {
+			return "", fmt.Errorf("failed to decode build output for service %s: %w", service.Name, err)
+		}
+
+		if stream, ok := message["stream"]; ok {
+			fmt.Print(stream)
+		}
+	}
+
+	return imageName, nil
+}
+
+// pushSingleServiceImage pushes a single service image.
+func pushSingleServiceImage(ctx context.Context, dockerCli *dockerclient.Client, serviceName string, imageName string) error {
+	ref, err := reference.ParseNormalizedNamed(imageName)
+	if err != nil {
+		return err
+	}
+
+	repoInfo, err := registry.ParseRepositoryInfo(ref)
+	if err != nil {
+		return err
+	}
+
+	registryKey := repoInfo.Index.Name
+	if repoInfo.Index.Official {
+		registryKey = registry.IndexServer
+	}
+
+	// Load the Docker config file with auth details, if available
+	configFile := config.LoadDefaultConfigFile(os.Stderr)
+
+	authConfig, err := configFile.GetAuthConfig(registryKey)
+	if err != nil {
+		return err
+	}
+
+	authJSON, err := json.Marshal(authConfig)
+	if err != nil {
+		return fmt.Errorf("failed to marshal auth config for registry %s: %w", registryKey, err)
+	}
+
+	authStr := base64.URLEncoding.EncodeToString(authJSON)
+
+	pushOptions := image.PushOptions{
+		RegistryAuth: authStr,
+	}
+	pushResponse, err := dockerCli.ImagePush(ctx, imageName, pushOptions)
+	if err != nil {
+		return fmt.Errorf("failed to push image %s: %w", imageName, err)
+	}
+	defer pushResponse.Close()
+
+	fmt.Printf("Pushing image %s for service %s\n", imageName, serviceName)
+
+	// Handle output and errors
+	decoder := json.NewDecoder(pushResponse)
+	for {
+		var message map[string]interface{}
+		if err := decoder.Decode(&message); err == io.EOF {
+			break
+		} else if err != nil {
+			return fmt.Errorf("failed to decode push output for image %s: %w", imageName, err)
+		}
+		if stream, ok := message["stream"]; ok {
+			fmt.Print(stream)
+		} else if errorMessage, ok := message["error"]; ok {
+			return fmt.Errorf("error pushing image %s: %s", imageName, errorMessage)
+		} else if status, ok := message["status"]; ok {
+			fmt.Printf("   %s\n", status)
+		}
+	}
+
+	fmt.Printf("Image %s pushed successfully.\n", imageName)
+	return nil
+}
+
+// pushServiceImages pushes all built service images to the registry.
+func pushServiceImages(ctx context.Context, dockerCli *dockerclient.Client, serviceImages map[string]string) error {
+	fmt.Printf("Pushing images...\n")
+	for serviceName, imageName := range serviceImages {
+		if err := pushSingleServiceImage(ctx, dockerCli, serviceName, imageName); err != nil {
+			return fmt.Errorf("push image for service %s: %w", serviceName, err)
+		}
+	}
+	return nil
+}