package dockerfile // import "github.com/docker/docker/builder/dockerfile" import ( "context" "runtime" "github.com/docker/docker/api/types/backend" "github.com/docker/docker/builder" dockerimage "github.com/docker/docker/image" specs "github.com/opencontainers/image-spec/specs-go/v1" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) type getAndMountFunc func(string, bool, *specs.Platform) (builder.Image, builder.ROLayer, error) // imageSources mounts images and provides a cache for mounted images. It tracks // all images so they can be unmounted at the end of the build. type imageSources struct { byImageID map[string]*imageMount mounts []*imageMount getImage getAndMountFunc } func newImageSources(ctx context.Context, options builderOptions) *imageSources { getAndMount := func(idOrRef string, localOnly bool, platform *specs.Platform) (builder.Image, builder.ROLayer, error) { pullOption := backend.PullOptionNoPull if !localOnly { if options.Options.PullParent { pullOption = backend.PullOptionForcePull } else { pullOption = backend.PullOptionPreferLocal } } return options.Backend.GetImageAndReleasableLayer(ctx, idOrRef, backend.GetImageAndLayerOptions{ PullOption: pullOption, AuthConfig: options.Options.AuthConfigs, Output: options.ProgressWriter.Output, Platform: platform, }) } return &imageSources{ byImageID: make(map[string]*imageMount), getImage: getAndMount, } } func (m *imageSources) Get(idOrRef string, localOnly bool, platform *specs.Platform) (*imageMount, error) { if im, ok := m.byImageID[idOrRef]; ok { return im, nil } image, layer, err := m.getImage(idOrRef, localOnly, platform) if err != nil { return nil, err } im := newImageMount(image, layer) m.Add(im) return im, nil } func (m *imageSources) Unmount() (retErr error) { for _, im := range m.mounts { if err := im.unmount(); err != nil { logrus.Error(err) retErr = err } } return } func (m *imageSources) Add(im *imageMount) { switch im.image { case nil: // set the OS for scratch images os := runtime.GOOS // Windows does not support scratch except for LCOW if runtime.GOOS == "windows" { os = "linux" } im.image = &dockerimage.Image{V1Image: dockerimage.V1Image{OS: os}} default: m.byImageID[im.image.ImageID()] = im } m.mounts = append(m.mounts, im) } // imageMount is a reference to an image that can be used as a builder.Source type imageMount struct { image builder.Image source builder.Source layer builder.ROLayer } func newImageMount(image builder.Image, layer builder.ROLayer) *imageMount { im := &imageMount{image: image, layer: layer} return im } func (im *imageMount) unmount() error { if im.layer == nil { return nil } if err := im.layer.Release(); err != nil { return errors.Wrapf(err, "failed to unmount previous build image %s", im.image.ImageID()) } im.layer = nil return nil } func (im *imageMount) Image() builder.Image { return im.image } func (im *imageMount) NewRWLayer() (builder.RWLayer, error) { return im.layer.NewRWLayer() } func (im *imageMount) ImageID() string { return im.image.ImageID() }