Add local build API for direct filesystem builds on MacOS and Windows

Adds /libpod/local/build endpoint, client bindings, and path translation
utilities to enable container builds from mounted directories to podman machine without tar uploads.

This optimization significantly speeds up build operations when working with remote Podman machines by eliminating redundant file transfers for already-accessible files.

Fixes: https://issues.redhat.com/browse/RUN-3249

Signed-off-by: Jan Rodák <[email protected]>

Author: Honny1

internal/localapi/types.go

@@ -5,3 +5,5 @@ type LocalAPIMap struct {
 	ClientPath string `json:"ClientPath,omitempty"`
 	RemotePath string `json:"RemotePath,omitempty"`
 }
+
+type TranslationLocalAPIMap map[string]string

internal/localapi/utils.go

@@ -154,3 +154,40 @@ func CheckPathOnRunningMachine(ctx context.Context, path string) (*LocalAPIMap,
 
 	return isPathAvailableOnMachine(mounts, vmType, path)
 }
+
+// CheckMultiplePathsOnRunningMachine checks if multiple paths are available on a running machine.
+// Returns a translation map of local-to-remote paths if all paths are accessible, false otherwise.
+func CheckMultiplePathsOnRunningMachine(ctx context.Context, paths []string) (TranslationLocalAPIMap, bool) {
+	result := TranslationLocalAPIMap{}
+
+	if machineMode := bindings.GetMachineMode(ctx); !machineMode {
+		logrus.Debug("Machine mode is not enabled, skipping machine check")
+		return nil, false
+	}
+
+	conn, err := bindings.GetClient(ctx)
+	if err != nil {
+		logrus.Debugf("Failed to get client connection: %v", err)
+		return nil, false
+	}
+
+	mounts, vmType, err := getMachineMountsAndVMType(conn.URI.String(), conn.URI)
+	if err != nil {
+		logrus.Debugf("Failed to get machine mounts: %v", err)
+		return nil, false
+	}
+
+	for _, path := range paths {
+		if err := fileutils.Exists(path); errors.Is(err, fs.ErrNotExist) {
+			logrus.Debugf("Path %s does not exist locally, skipping machine check", path)
+			return nil, false
+		}
+		mapping, found := isPathAvailableOnMachine(mounts, vmType, path)
+		if !found {
+			logrus.Debugf("Path %s is not available on the running machine", path)
+			return nil, false
+		}
+		result[path] = mapping.RemotePath
+	}
+	return result, true
+}

internal/localapi/utils_unsupported.go

@@ -12,3 +12,8 @@ func CheckPathOnRunningMachine(ctx context.Context, path string) (*LocalAPIMap,
 	logrus.Debug("CheckPathOnRunningMachine is not supported")
 	return nil, false
 }
+
+func CheckMultiplePathsOnRunningMachine(ctx context.Context, paths []string) (TranslationLocalAPIMap, bool) {
+	logrus.Debug("CheckMultiplePathsOnRunningMachine is not supported")
+	return nil, false
+}

pkg/api/handlers/compat/images_build.go

@@ -135,6 +135,40 @@ type BuildContext struct {
 	IgnoreFile              string
 }
 
+func (b *BuildContext) validatePaths() error {
+	if err := validateLocalPath(b.ContextDirectory); err != nil {
+		return err
+	}
+
+	for _, containerfile := range b.ContainerFiles {
+		if err := validateLocalPath(containerfile); err != nil {
+			return err
+		}
+	}
+
+	for _, ctx := range b.AdditionalBuildContexts {
+		if ctx.IsURL || ctx.IsImage {
+			continue
+		}
+		if err := validateLocalPath(ctx.Value); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func validateLocalPath(path string) error {
+	if !filepath.IsAbs(path) {
+		return fmt.Errorf("path %q is not absolute", path)
+	}
+
+	if err := fileutils.Exists(path); err != nil {
+		return err
+	}
+	return nil
+}
+
 // genSpaceErr wraps filesystem errors to provide more context for disk space issues.
 func genSpaceErr(err error) error {
 	if errors.Is(err, syscall.ENOSPC) {
@@ -257,10 +291,17 @@ func processBuildContext(query url.Values, r *http.Request, buildContext *BuildC
 
 			for _, containerfile := range m {
 				// Add path to containerfile iff it is not URL
-				if !strings.HasPrefix(containerfile, "http://") && !strings.HasPrefix(containerfile, "https://") {
+				if strings.HasPrefix(containerfile, "http://") || strings.HasPrefix(containerfile, "https://") {
+					continue
+				}
+
+				if filepath.IsAbs(containerfile) {
+					containerfile = filepath.Clean(filepath.FromSlash(containerfile))
+				} else {
 					containerfile = filepath.Join(buildContext.ContextDirectory,
 						filepath.Clean(filepath.FromSlash(containerfile)))
 				}
+
 				buildContext.ContainerFiles = append(buildContext.ContainerFiles, containerfile)
 			}
 			dockerFileSet = true
@@ -819,7 +860,104 @@ func executeBuild(runtime *libpod.Runtime, w http.ResponseWriter, r *http.Reques
 	}
 }
 
+// handleLocalBuildContexts processes build contexts for local builds using filesystem paths.
+// It extracts the local context directory and processes additional build contexts.
+func handleLocalBuildContexts(query url.Values, anchorDir string) (*BuildContext, error) {
+	localContextDir := query.Get("localcontextdir")
+	if localContextDir == "" {
+		return nil, fmt.Errorf("localcontextdir cannot be empty")
+	}
+
+	out := &BuildContext{
+		ContextDirectory:        filepath.Clean(localContextDir),
+		AdditionalBuildContexts: make(map[string]*buildahDefine.AdditionalBuildContext),
+	}
+
+	for _, url := range query["additionalbuildcontexts"] {
+		name, value, found := strings.Cut(url, "=")
+		if !found {
+			return nil, fmt.Errorf("invalid additional build context format: %q", url)
+		}
+
+		logrus.Debugf("name: %q, context: %q", name, value)
+
+		switch {
+		case strings.HasPrefix(value, "url:"):
+			value = strings.TrimPrefix(value, "url:")
+			tempDir, subdir, err := buildahDefine.TempDirForURL(anchorDir, "buildah", value)
+			if err != nil {
+				return nil, fmt.Errorf("downloading URL %q: %w", name, err)
+			}
+
+			contextPath := filepath.Join(tempDir, subdir)
+			out.AdditionalBuildContexts[name] = &buildahDefine.AdditionalBuildContext{
+				IsURL:           true,
+				IsImage:         false,
+				Value:           contextPath,
+				DownloadedCache: contextPath,
+			}
+		case strings.HasPrefix(value, "image:"):
+			value = strings.TrimPrefix(value, "image:")
+			out.AdditionalBuildContexts[name] = &buildahDefine.AdditionalBuildContext{
+				IsURL:   false,
+				IsImage: true,
+				Value:   value,
+			}
+		case strings.HasPrefix(value, "localpath:"):
+			value = strings.TrimPrefix(value, "localpath:")
+			fmt.Printf("Using local path %q for additional build context %q\n", value, name)
+			out.AdditionalBuildContexts[name] = &buildahDefine.AdditionalBuildContext{
+				IsURL:   false,
+				IsImage: false,
+				Value:   filepath.Clean(value),
+			}
+		}
+	}
+	return out, nil
+}
+
+// getLocalBuildContext processes build contexts from HTTP request to a BuildContext struct.
+func getLocalBuildContext(r *http.Request, query url.Values, anchorDir string, multipart bool) (*BuildContext, error) {
+	// Handle build contexts (extract from tar/multipart)
+	buildContext, err := handleLocalBuildContexts(query, anchorDir)
+	if err != nil {
+		return nil, utils.GetInternalServerError(genSpaceErr(err))
+	}
+
+	// Process build context and container files
+	buildContext, err = processBuildContext(query, r, buildContext, anchorDir)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := buildContext.validatePaths(); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil, utils.GetFileNotFoundError(err)
+		}
+		return nil, utils.GetGenericBadRequestError(err)
+	}
+
+	// Process dockerignore
+	_, ignoreFile, err := util.ParseDockerignore(buildContext.ContainerFiles, buildContext.ContextDirectory)
+	if err != nil {
+		return nil, utils.GetInternalServerError(fmt.Errorf("processing ignore file: %w", err))
+	}
+	buildContext.IgnoreFile = ignoreFile
+
+	return buildContext, nil
+}
+
+func LocalBuildImage(w http.ResponseWriter, r *http.Request) {
+	buildImage(w, r, getLocalBuildContext)
+}
+
 func BuildImage(w http.ResponseWriter, r *http.Request) {
+	buildImage(w, r, getBuildContext)
+}
+
+type getBuildContextFunc func(r *http.Request, query url.Values, anchorDir string, multipart bool) (*BuildContext, error)
+
+func buildImage(w http.ResponseWriter, r *http.Request, getBuildContextFunc getBuildContextFunc) {
 	// Create temporary directory for build context
 	anchorDir, err := os.MkdirTemp(parse.GetTempDir(), "libpod_builder")
 	if err != nil {
@@ -850,7 +988,7 @@ func BuildImage(w http.ResponseWriter, r *http.Request) {
 	}
 	queryValues := r.URL.Query()
 
-	buildContext, err := getBuildContext(r, queryValues, anchorDir, multipart)
+	buildContext, err := getBuildContextFunc(r, queryValues, anchorDir, multipart)
 	if err != nil {
 		utils.ProcessBuildError(w, err)
 		return

pkg/api/handlers/swagger/errors.go

@@ -16,6 +16,13 @@ type imageNotFound struct {
 	Body errorhandling.ErrorModel
 }
 
+// No such file
+// swagger:response
+type fileNotFound struct {
+	// in:body
+	Body errorhandling.ErrorModel
+}
+
 // No such container
 // swagger:response
 type containerNotFound struct {

pkg/api/handlers/utils/errors.go

@@ -118,6 +118,10 @@ func (e *BuildError) Error() string {
 	return e.err.Error()
 }
 
+func GetFileNotFoundError(err error) *BuildError {
+	return &BuildError{code: http.StatusNotFound, err: err}
+}
+
 func GetBadRequestError(key, value string, err error) *BuildError {
 	return &BuildError{code: http.StatusBadRequest, err: fmt.Errorf("failed to parse query parameter '%s': %q: %w", key, value, err)}
 }