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images, services/images: implement image service

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Server and Client images of the image store are now provided. We have
created an image metadata interface and converted the bolt functions to
implement that interface over an transaction. A remote client
implementation is provided that implements the same interface.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
This commit is contained in:
Stephen J Day 2017-04-03 18:33:24 -07:00
parent a5c9d6d41b
commit 1ea809dc2a
No known key found for this signature in database
GPG key ID: 67B3DED84EDC823F
5 changed files with 280 additions and 45 deletions
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16
images/image.go
View file

@ -14,8 +14,8 @@ import (
// Image provides the model for how containerd views container images.
type Image struct {
Name string
Descriptor ocispec.Descriptor
Name string
Target ocispec.Descriptor
}
// TODO(stevvooe): Many of these functions make strong platform assumptions,
@ -29,9 +29,9 @@ type Image struct {
func (image *Image) Config(ctx context.Context, provider content.Provider) (ocispec.Descriptor, error) {
var configDesc ocispec.Descriptor
return configDesc, Walk(ctx, HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
switch image.Descriptor.MediaType {
switch image.Target.MediaType {
case MediaTypeDockerSchema2Manifest, ocispec.MediaTypeImageManifest:
rc, err := provider.Reader(ctx, image.Descriptor.Digest)
rc, err := provider.Reader(ctx, image.Target.Digest)
if err != nil {
return nil, err
}
@ -54,7 +54,7 @@ func (image *Image) Config(ctx context.Context, provider content.Provider) (ocis
return nil, errors.New("could not resolve config")
}
}), image.Descriptor)
}), image.Target)
}
// RootFS returns the unpacked diffids that make up and images rootfs.
@ -91,10 +91,10 @@ func (image *Image) RootFS(ctx context.Context, provider content.Provider) ([]di
func (image *Image) Size(ctx context.Context, provider content.Provider) (int64, error) {
var size int64
return size, Walk(ctx, HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
switch image.Descriptor.MediaType {
switch image.Target.MediaType {
case MediaTypeDockerSchema2Manifest, ocispec.MediaTypeImageManifest:
size += desc.Size
rc, err := provider.Reader(ctx, image.Descriptor.Digest)
rc, err := provider.Reader(ctx, image.Target.Digest)
if err != nil {
return nil, err
}
@ -121,5 +121,5 @@ func (image *Image) Size(ctx context.Context, provider content.Provider) (int64,
return nil, errors.New("unsupported type")
}
}), image.Descriptor)
}), image.Target)
}

77
images/storage.go
View file

@ -1,6 +1,7 @@
package images
import (
"context"
"encoding/binary"
"fmt"
@ -8,12 +9,30 @@ import (
"github.com/containerd/containerd/log"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
var (
errImageUnknown = fmt.Errorf("image: unknown")
ErrExists = errors.New("images: exists")
ErrNotFound = errors.New("images: not found")
)
type Store interface {
Put(ctx context.Context, name string, desc ocispec.Descriptor) error
Get(ctx context.Context, name string) (Image, error)
List(ctx context.Context) ([]Image, error)
Delete(ctx context.Context, name string) error
}
// IsNotFound returns true if the error is due to a missing image.
func IsNotFound(err error) bool {
return errors.Cause(err) == ErrNotFound
}
func IsExists(err error) bool {
return errors.Cause(err) == ErrExists
}
var (
bucketKeyStorageVersion = []byte("v1")
bucketKeyImages = []byte("images")
@ -26,6 +45,8 @@ var (
// "metadata" store. For now, it is bound tightly to the local machine and bolt
// but we can take this and use it to define a service interface.
// InitDB will initialize the database for use. The database must be opened for
// write and the caller must not be holding an open transaction.
func InitDB(db *bolt.DB) error {
log.L.Debug("init db")
return db.Update(func(tx *bolt.Tx) error {
@ -34,8 +55,28 @@ func InitDB(db *bolt.DB) error {
})
}
func Register(tx *bolt.Tx, name string, desc ocispec.Descriptor) error {
return withImagesBucket(tx, func(bkt *bolt.Bucket) error {
func NewImageStore(tx *bolt.Tx) Store {
return &storage{tx: tx}
}
type storage struct {
tx *bolt.Tx
}
func (s *storage) Get(ctx context.Context, name string) (Image, error) {
var image Image
if err := withImageBucket(s.tx, name, func(bkt *bolt.Bucket) error {
image.Name = name
return readImage(&image, bkt)
}); err != nil {
return Image{}, err
}
return image, nil
}
func (s *storage) Put(ctx context.Context, name string, desc ocispec.Descriptor) error {
return withImagesBucket(s.tx, func(bkt *bolt.Bucket) error {
ibkt, err := bkt.CreateBucketIfNotExists([]byte(name))
if err != nil {
return err
@ -65,22 +106,10 @@ func Register(tx *bolt.Tx, name string, desc ocispec.Descriptor) error {
})
}
func Get(tx *bolt.Tx, name string) (Image, error) {
var image Image
if err := withImageBucket(tx, name, func(bkt *bolt.Bucket) error {
image.Name = name
return readImage(&image, bkt)
}); err != nil {
return Image{}, err
}
return image, nil
}
func List(tx *bolt.Tx) ([]Image, error) {
func (s *storage) List(ctx context.Context) ([]Image, error) {
var images []Image
if err := withImagesBucket(tx, func(bkt *bolt.Bucket) error {
if err := withImagesBucket(s.tx, func(bkt *bolt.Bucket) error {
return bkt.ForEach(func(k, v []byte) error {
var (
image = Image{
@ -103,8 +132,8 @@ func List(tx *bolt.Tx) ([]Image, error) {
return images, nil
}
func Delete(tx *bolt.Tx, name string) error {
return withImagesBucket(tx, func(bkt *bolt.Bucket) error {
func (s *storage) Delete(ctx context.Context, name string) error {
return withImagesBucket(s.tx, func(bkt *bolt.Bucket) error {
return bkt.DeleteBucket([]byte(name))
})
}
@ -119,11 +148,11 @@ func readImage(image *Image, bkt *bolt.Bucket) error {
// keys, rather than full arrays.
switch string(k) {
case string(bucketKeyDigest):
image.Descriptor.Digest = digest.Digest(v)
image.Target.Digest = digest.Digest(v)
case string(bucketKeyMediaType):
image.Descriptor.MediaType = string(v)
image.Target.MediaType = string(v)
case string(bucketKeySize):
image.Descriptor.Size, _ = binary.Varint(v)
image.Target.Size, _ = binary.Varint(v)
}
return nil
@ -149,7 +178,7 @@ func createBucketIfNotExists(tx *bolt.Tx, keys ...[]byte) (*bolt.Bucket, error)
func withImagesBucket(tx *bolt.Tx, fn func(bkt *bolt.Bucket) error) error {
bkt := getImagesBucket(tx)
if bkt == nil {
return errImageUnknown
return ErrNotFound
}
return fn(bkt)
@ -158,7 +187,7 @@ func withImagesBucket(tx *bolt.Tx, fn func(bkt *bolt.Bucket) error) error {
func withImageBucket(tx *bolt.Tx, name string, fn func(bkt *bolt.Bucket) error) error {
bkt := getImageBucket(tx, name)
if bkt == nil {
return errImageUnknown
return ErrNotFound
}
return fn(bkt)