add CTRL+e for extracting current focused file

cmd/root.go

@@ -93,6 +93,7 @@ func initConfig() {
 	viper.SetDefault("keybinding.toggle-modified-files", "ctrl+m")
 	viper.SetDefault("keybinding.toggle-unmodified-files", "ctrl+u")
 	viper.SetDefault("keybinding.toggle-wrap-tree", "ctrl+p")
+	viper.SetDefault("keybinding.extract-file", "ctrl+e")
 	viper.SetDefault("keybinding.page-up", "pgup")
 	viper.SetDefault("keybinding.page-down", "pgdn")
 

dive/image/docker/archive_resolver.go

@@ -30,3 +30,7 @@ func (r *archiveResolver) Fetch(path string) (*image.Image, error) {
 func (r *archiveResolver) Build(args []string) (*image.Image, error) {
 	return nil, fmt.Errorf("build option not supported for docker archive resolver")
 }
+
+func (r *archiveResolver) Extract(id string, l string, p string) error {
+	return fmt.Errorf("not implemented")
+}

dive/image/docker/engine_resolver.go

@@ -42,6 +42,19 @@ func (r *engineResolver) Build(args []string) (*image.Image, error) {
 	return r.Fetch(id)
 }
 
+func (r *engineResolver) Extract(id string, l string, p string) error {
+	reader, err := r.fetchArchive(id)
+	if err != nil {
+		return err
+	}
+
+	if err := ExtractFromImage(io.NopCloser(reader), l, p); err == nil {
+		return nil
+	}
+
+	return fmt.Errorf("unable to extract from image '%s': %+v", id, err)
+}
+
 func (r *engineResolver) fetchArchive(id string) (io.ReadCloser, error) {
 	var err error
 	var dockerClient *client.Client

dive/image/docker/image_archive.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"os"
 	"path"
+	"path/filepath"
 	"strings"
 
 	"github.com/wagoodman/dive/dive/filetree"
@@ -204,3 +205,80 @@ func (img *ImageArchive) ToImage() (*image.Image, error) {
 		Layers: layers,
 	}, nil
 }
+
+func ExtractFromImage(tarFile io.ReadCloser, l string, p string) error {
+	tarReader := tar.NewReader(tarFile)
+
+	for {
+		header, err := tarReader.Next()
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+
+		name := header.Name
+
+		switch header.Typeflag {
+		case tar.TypeReg:
+			if name == l {
+				err = extractInner(tar.NewReader(tarReader), p)
+				if err != nil {
+					return err
+				}
+				return nil
+			}
+		default:
+			continue
+		}
+	}
+
+	return nil
+}
+
+func extractInner(reader *tar.Reader, p string) error {
+	target := strings.TrimPrefix(p, "/")
+
+	for {
+		header, err := reader.Next()
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+
+		name := header.Name
+
+		switch header.Typeflag {
+		case tar.TypeReg:
+			if strings.HasPrefix(name, target) {
+				err := os.MkdirAll(filepath.Dir(name), 0755)
+				if err != nil {
+					return err
+				}
+
+				out, err := os.Create(name)
+				if err != nil {
+					return err
+				}
+
+				_, err = io.Copy(out, reader)
+				if err != nil {
+					return err
+				}
+			}
+		default:
+			continue
+		}
+	}
+
+	return nil
+}

dive/image/podman/resolver.go

@@ -36,6 +36,21 @@ func (r *resolver) Fetch(id string) (*image.Image, error) {
 	return nil, fmt.Errorf("unable to resolve image '%s': %+v", id, err)
 }
 
+func (r *resolver) Extract(id string, l string, p string) error {
+	// todo: add podman fetch attempt via varlink first...
+
+	err, reader := streamPodmanCmd("image", "save", id)
+	if err != nil {
+		return err
+	}
+
+	if err := docker.ExtractFromImage(io.NopCloser(reader), l, p); err == nil {
+		return nil
+	}
+
+	return fmt.Errorf("unable to extract from image '%s': %+v", id, err)
+}
+
 func (r *resolver) resolveFromDockerArchive(id string) (*image.Image, error) {
 	err, reader := streamPodmanCmd("image", "save", id)
 	if err != nil {

dive/image/podman/resolver_unsupported.go

@@ -22,3 +22,7 @@ func (r *resolver) Build(args []string) (*image.Image, error) {
 func (r *resolver) Fetch(id string) (*image.Image, error) {
 	return nil, fmt.Errorf("unsupported platform")
 }
+
+func (r *resolver) Extract(id string, l string, p string) error {
+	return fmt.Errorf("unsupported platform")
+}

dive/image/resolver.go

@@ -3,4 +3,5 @@ package image
 type Resolver interface {
 	Fetch(id string) (*Image, error)
 	Build(options []string) (*Image, error)
+	Extract(id string, layer string, path string) error
 }

go.mod

@@ -55,6 +55,7 @@ require (
 	golang.org/x/sys v0.9.0 // indirect
 	golang.org/x/term v0.9.0 // indirect
 	golang.org/x/text v0.10.0 // indirect
+	golang.org/x/time v0.0.0-20191024005414-555d28b269f0 // indirect
 	gopkg.in/yaml.v2 v2.2.8 // indirect
 	gotest.tools v2.2.0+incompatible // indirect
 	gotest.tools/v3 v3.5.0 // indirect

go.sum

@@ -240,8 +240,9 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.10.0 h1:UpjohKhiEgNc0CSauXmwYftY1+LlaC75SJwh0SgCX58=
 golang.org/x/text v0.10.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
-golang.org/x/time v0.0.0-20190308202827-9d24e82272b4 h1:SvFZT6jyqRaOeXpc5h/JSfZenJ2O330aBsf7JfSUXmQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
+golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
+golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

runtime/run.go

@@ -108,7 +108,7 @@ func run(enableUi bool, options Options, imageResolver image.Resolver, events ev
 			// enough sleep will prevent this behavior (todo: remove this hack)
 			time.Sleep(100 * time.Millisecond)
 
-			err = ui.Run(options.Image, analysis, treeStack)
+			err = ui.Run(options.Image, imageResolver, analysis, treeStack)
 			if err != nil {
 				events.exitWithError(err)
 				return

runtime/run_test.go

@@ -16,6 +16,10 @@ import (
 
 type defaultResolver struct{}
 
+func (r *defaultResolver) Extract(id string, l string, p string) error {
+	return nil
+}
+
 func (r *defaultResolver) Fetch(id string) (*image.Image, error) {
 	archive, err := docker.TestLoadArchive("../.data/test-docker-image.tar")
 	if err != nil {
@@ -30,6 +34,10 @@ func (r *defaultResolver) Build(args []string) (*image.Image, error) {
 
 type failedBuildResolver struct{}
 
+func (r *failedBuildResolver) Extract(id string, l string, p string) error {
+	return fmt.Errorf("some extract failure")
+}
+
 func (r *failedBuildResolver) Fetch(id string) (*image.Image, error) {
 	archive, err := docker.TestLoadArchive("../.data/test-docker-image.tar")
 	if err != nil {
@@ -44,6 +52,10 @@ func (r *failedBuildResolver) Build(args []string) (*image.Image, error) {
 
 type failedFetchResolver struct{}
 
+func (r *failedFetchResolver) Extract(id string, l string, p string) error {
+	return fmt.Errorf("some extract failure")
+}
+
 func (r *failedFetchResolver) Fetch(id string) (*image.Image, error) {
 	return nil, fmt.Errorf("some fetch failure")
 }

runtime/ui/app.go

@@ -27,13 +27,13 @@ var (
 	appSingleton *app
 )
 
-func newApp(gui *gocui.Gui, imageName string, analysis *image.AnalysisResult, cache filetree.Comparer) (*app, error) {
+func newApp(gui *gocui.Gui, imageName string, resolver image.Resolver, analysis *image.AnalysisResult, cache filetree.Comparer) (*app, error) {
 	var err error
 	once.Do(func() {
 		var controller *Controller
 		var globalHelpKeys []*key.Binding
 
-		controller, err = NewCollection(gui, imageName, analysis, cache)
+		controller, err = NewCollection(gui, imageName, resolver, analysis, cache)
 		if err != nil {
 			return
 		}
@@ -134,7 +134,7 @@ func (a *app) quit() error {
 }
 
 // Run is the UI entrypoint.
-func Run(imageName string, analysis *image.AnalysisResult, treeStack filetree.Comparer) error {
+func Run(imageName string, resolver image.Resolver, analysis *image.AnalysisResult, treeStack filetree.Comparer) error {
 	var err error
 
 	g, err := gocui.NewGui(gocui.OutputNormal, true)
@@ -143,7 +143,7 @@ func Run(imageName string, analysis *image.AnalysisResult, treeStack filetree.Co
 	}
 	defer g.Close()
 
-	_, err = newApp(g, imageName, analysis, treeStack)
+	_, err = newApp(g, imageName, resolver, analysis, treeStack)
 	if err != nil {
 		return err
 	}

runtime/ui/controller.go

@@ -13,19 +13,23 @@ import (
 )
 
 type Controller struct {
-	gui   *gocui.Gui
-	views *view.Views
+	gui       *gocui.Gui
+	views     *view.Views
+	resolver  image.Resolver
+	imageName string
 }
 
-func NewCollection(g *gocui.Gui, imageName string, analysis *image.AnalysisResult, cache filetree.Comparer) (*Controller, error) {
+func NewCollection(g *gocui.Gui, imageName string, resolver image.Resolver, analysis *image.AnalysisResult, cache filetree.Comparer) (*Controller, error) {
 	views, err := view.NewViews(g, imageName, analysis, cache)
 	if err != nil {
 		return nil, err
 	}
 
 	controller := &Controller{
-		gui:   g,
-		views: views,
+		gui:       g,
+		views:     views,
+		resolver:  resolver,
+		imageName: imageName,
 	}
 
 	// layer view cursor down event should trigger an update in the file tree
@@ -34,6 +38,9 @@ func NewCollection(g *gocui.Gui, imageName string, analysis *image.AnalysisResul
 	// update the status pane when a filetree option is changed by the user
 	controller.views.Tree.AddViewOptionChangeListener(controller.onFileTreeViewOptionChange)
 
+	// update the status pane when a filetree option is changed by the user
+	controller.views.Tree.AddViewExtractListener(controller.onFileTreeViewExtract)
+
 	// update the tree view while the user types into the filter view
 	controller.views.Filter.AddFilterEditListener(controller.onFilterEdit)
 
@@ -53,6 +60,10 @@ func NewCollection(g *gocui.Gui, imageName string, analysis *image.AnalysisResul
 	return controller, nil
 }
 
+func (c *Controller) onFileTreeViewExtract(p string) error {
+	return c.resolver.Extract(c.imageName, c.views.LayerDetails.CurrentLayer.Id, p)
+}
+
 func (c *Controller) onFileTreeViewOptionChange() error {
 	err := c.views.Status.Update()
 	if err != nil {

runtime/ui/view/filetree.go

@@ -17,6 +17,8 @@ import (
 
 type ViewOptionChangeListener func() error
 
+type ViewExtractListener func(string) error
+
 // FileTree holds the UI objects and data models for populating the right pane. Specifically the pane that
 // shows selected layer or aggregate file ASCII tree.
 type FileTree struct {
@@ -29,6 +31,7 @@ type FileTree struct {
 
 	filterRegex         *regexp.Regexp
 	listeners           []ViewOptionChangeListener
+	extractListeners    []ViewExtractListener
 	helpKeys            []*key.Binding
 	requestedWidthRatio float64
 }
@@ -60,6 +63,10 @@ func (v *FileTree) AddViewOptionChangeListener(listener ...ViewOptionChangeListe
 	v.listeners = append(v.listeners, listener...)
 }
 
+func (v *FileTree) AddViewExtractListener(listener ...ViewExtractListener) {
+	v.extractListeners = append(v.extractListeners, listener...)
+}
+
 func (v *FileTree) SetTitle(title string) {
 	v.title = title
 }
@@ -103,6 +110,11 @@ func (v *FileTree) Setup(view, header *gocui.View) error {
 			OnAction:   v.toggleSortOrder,
 			Display:    "Toggle sort order",
 		},
+		{
+			ConfigKeys: []string{"keybinding.extract-file"},
+			OnAction:   v.extractFile,
+			Display:    "Extract File",
+		},
 		{
 			ConfigKeys: []string{"keybinding.toggle-added-files"},
 			OnAction:   func() error { return v.toggleShowDiffType(filetree.Added) },
@@ -303,6 +315,18 @@ func (v *FileTree) toggleSortOrder() error {
 	return v.Render()
 }
 
+func (v *FileTree) extractFile() error {
+	node := v.vm.CurrentNode(v.filterRegex)
+	for _, listener := range v.extractListeners {
+		err := listener(node.Path())
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func (v *FileTree) toggleWrapTree() error {
 	v.view.Wrap = !v.view.Wrap
 	return nil

runtime/ui/viewmodel/filetree.go

@@ -161,6 +161,11 @@ func (vm *FileTreeViewModel) CursorDown() bool {
 	return true
 }
 
+// CursorLeft moves the cursor up until we reach the Parent Node or top of the tree
+func (vm *FileTreeViewModel) CurrentNode(filterRegex *regexp.Regexp) *filetree.FileNode {
+	return vm.getAbsPositionNode(filterRegex)
+}
+
 // CursorLeft moves the cursor up until we reach the Parent Node or top of the tree
 func (vm *FileTreeViewModel) CursorLeft(filterRegex *regexp.Regexp) error {
 	var visitor func(*filetree.FileNode) error