moby/builder/dockerfile/imagecontext.go
Chris Price c21a3cf432 Add variant to image.Image and legacy builder
This commit adds the image variant to the image.(Image) type and
updates related functionality. Images built from another will
inherit the OS, architecture and variant.

Note that if a base image does not specify an architecture, the
local machine's architecture is used for inherited images. On the
other hand, the variant is set equal to the parent image's variant,
even when the parent image's variant is unset.

The legacy builder is also updated to allow the user to specify
a '--platform' argument on the command line when creating an image
FROM scratch. A complete platform specification, including variant,
is supported. The built image will include the variant, as will any
derived images.

Signed-off-by: Chris Price <chris.price@docker.com>
2019-09-24 22:18:16 +00:00

132 lines
3.3 KiB
Go

package dockerfile // import "github.com/docker/docker/builder/dockerfile"
import (
"context"
"runtime"
"github.com/containerd/containerd/platforms"
"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, platform)
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, platform *specs.Platform) {
switch im.image {
case nil:
// Set the platform for scratch images
if platform == nil {
p := platforms.DefaultSpec()
platform = &p
}
// Windows does not support scratch except for LCOW
os := platform.OS
if runtime.GOOS == "windows" {
os = "linux"
}
im.image = &dockerimage.Image{V1Image: dockerimage.V1Image{
OS: os,
Architecture: platform.Architecture,
Variant: platform.Variant,
}}
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
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()
}