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Make Diff/Apply plugable

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Signed-off-by: Volodymyr Burenin <vburenin@gmail.com>
This commit is contained in:
Volodymyr Burenin 2017-06-01 18:38:33 -05:00
parent 35d74aa9d8
commit 3c76a667b6
11 changed files with 249 additions and 143 deletions
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1
cmd/containerd/builtins.go
View File

@ -2,6 +2,7 @@ package main
// register containerd builtins here
import (
_ "github.com/containerd/containerd/differ"
_ "github.com/containerd/containerd/services/containers"
_ "github.com/containerd/containerd/services/content"
_ "github.com/containerd/containerd/services/diff"

3
cmd/containerd/config.go
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@ -49,6 +49,9 @@ type config struct {
Metrics metricsConfig `toml:"metrics"`
// Snapshotter specifies which snapshot driver to use
Snapshotter string `toml:"snapshotter"`
// Differ specifies which differ to use. Differ is tightly coupled with the snapshotter
// so not all combinations may work.
Differ string `toml:"differ"`
// Plugins provides plugin specific configuration for the initialization of a plugin
Plugins map[string]toml.Primitive `toml:"plugins"`
// Enable containerd as a subreaper

1
cmd/containerd/config_linux.go
View File

@ -12,5 +12,6 @@ func defaultConfig() *config {
Address: "/run/containerd/debug.sock",
},
Snapshotter: "overlay",
Differ: "base",
}
}

1
cmd/containerd/config_unix.go
View File

@ -14,5 +14,6 @@ func defaultConfig() *config {
Address: "/run/containerd/debug.sock",
},
Snapshotter: "naive",
Differ: "base",
}
}

1
cmd/containerd/config_windows.go
View File

@ -17,5 +17,6 @@ func defaultConfig() *config {
Address: `\\.\pipe\containerd-debug`,
},
Snapshotter: "windows",
Differ: "base",
}
}

47
cmd/containerd/main.go
View File

@ -130,7 +130,13 @@ func main() {
if err != nil {
return err
}
services, err := loadServices(runtimes, store, snapshotter, meta)
differ, err := loadDiffer(snapshotter, store)
if err != nil {
return err
}
services, err := loadServices(runtimes, store, snapshotter, meta, differ)
if err != nil {
return err
}
@ -351,6 +357,40 @@ func loadSnapshotter(store content.Store) (snapshot.Snapshotter, error) {
return nil, fmt.Errorf("snapshotter not loaded: %v", conf.Snapshotter)
}
func loadDiffer(snapshotter snapshot.Snapshotter, store content.Store) (plugin.Differ, error) {
for name, sr := range plugin.Registrations() {
if sr.Type != plugin.DiffPlugin {
continue
}
moduleName := fmt.Sprintf("diff-%s", conf.Differ)
if name != moduleName {
continue
}
log.G(global).Infof("loading differ plugin %q...", name)
ic := &plugin.InitContext{
Root: conf.Root,
State: conf.State,
Content: store,
Snapshotter: snapshotter,
Context: log.WithModule(global, moduleName),
}
if sr.Config != nil {
if err := conf.decodePlugin(name, sr.Config); err != nil {
return nil, err
}
ic.Config = sr.Config
}
sn, err := sr.Init(ic)
if err != nil {
return nil, err
}
return sn.(plugin.Differ), nil
}
return nil, fmt.Errorf("differ not loaded: %v", conf.Differ)
}
func newGRPCServer() *grpc.Server {
s := grpc.NewServer(
grpc.UnaryInterceptor(interceptor),
@ -359,7 +399,9 @@ func newGRPCServer() *grpc.Server {
return s
}
func loadServices(runtimes map[string]plugin.Runtime, store content.Store, sn snapshot.Snapshotter, meta *bolt.DB) ([]plugin.Service, error) {
func loadServices(runtimes map[string]plugin.Runtime,
store content.Store, sn snapshot.Snapshotter,
meta *bolt.DB, differ plugin.Differ) ([]plugin.Service, error) {
var o []plugin.Service
for name, sr := range plugin.Registrations() {
if sr.Type != plugin.GRPCPlugin {
@ -374,6 +416,7 @@ func loadServices(runtimes map[string]plugin.Runtime, store content.Store, sn sn
Content: store,
Meta: meta,
Snapshotter: sn,
Differ: differ,
}
if sr.Config != nil {
if err := conf.decodePlugin(name, sr.Config); err != nil {

164
differ/differ.go Normal file
View File

@ -0,0 +1,164 @@
package differ
import (
"io"
"io/ioutil"
"os"
"github.com/containerd/containerd/archive"
"github.com/containerd/containerd/archive/compression"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/mount"
"github.com/containerd/containerd/plugin"
"github.com/containerd/containerd/snapshot"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
"golang.org/x/net/context"
)
func init() {
plugin.Register("diff-base", &plugin.Registration{
Type: plugin.DiffPlugin,
Init: func(ic *plugin.InitContext) (interface{}, error) {
return newBaseDiff(ic.Content, ic.Snapshotter)
},
})
}
type BaseDiff struct {
store content.Store
snapshotter snapshot.Snapshotter
}
var _ plugin.Differ = &BaseDiff{}
var emptyDesc = ocispec.Descriptor{}
func newBaseDiff(store content.Store, snapshotter snapshot.Snapshotter) (*BaseDiff, error) {
return &BaseDiff{
store: store,
snapshotter: snapshotter,
}, nil
}
func (s *BaseDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount) (ocispec.Descriptor, error) {
// TODO: Check for supported media types
dir, err := ioutil.TempDir("", "extract-")
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(dir)
if err := mount.MountAll(mounts, dir); err != nil {
return emptyDesc, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(dir, 0)
r, err := s.store.Reader(ctx, desc.Digest)
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to get reader from content store")
}
defer r.Close()
// TODO: only decompress stream if media type is compressed
ds, err := compression.DecompressStream(r)
if err != nil {
return emptyDesc, err
}
defer ds.Close()
digester := digest.Canonical.Digester()
rc := &readCounter{
r: io.TeeReader(ds, digester.Hash()),
}
if _, err := archive.Apply(ctx, dir, rc); err != nil {
return emptyDesc, err
}
// Read any trailing data
if _, err := io.Copy(ioutil.Discard, rc); err != nil {
return emptyDesc, err
}
return ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Size: rc.c,
Digest: digester.Digest(),
}, nil
}
func (s *BaseDiff) DiffMounts(ctx context.Context, lower, upper []mount.Mount, media, ref string) (ocispec.Descriptor, error) {
aDir, err := ioutil.TempDir("", "left-")
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(aDir)
bDir, err := ioutil.TempDir("", "right-")
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(bDir)
if err := mount.MountAll(lower, aDir); err != nil {
return emptyDesc, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(aDir, 0)
if err := mount.MountAll(upper, bDir); err != nil {
return emptyDesc, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(bDir, 0)
cw, err := s.store.Writer(ctx, ref, 0, "")
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to open writer")
}
// TODO: Validate media type
// TODO: Support compressed media types (link compressed to uncompressed)
//dgstr := digest.SHA256.Digester()
//wc := &writeCounter{}
//compressed, err := compression.CompressStream(cw, compression.Gzip)
//if err != nil {
// return nil, errors.Wrap(err, "failed to get compressed stream")
//}
//err = archive.WriteDiff(ctx, io.MultiWriter(compressed, dgstr.Hash(), wc), lowerDir, upperDir)
//compressed.Close()
err = archive.WriteDiff(ctx, cw, aDir, bDir)
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to write diff")
}
dgst := cw.Digest()
if err := cw.Commit(0, dgst); err != nil {
return emptyDesc, errors.Wrap(err, "failed to commit")
}
info, err := s.store.Info(ctx, dgst)
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to get info from content store")
}
return ocispec.Descriptor{
MediaType: media,
Size: info.Size,
Digest: info.Digest,
}, nil
}
type readCounter struct {
r io.Reader
c int64
}
func (rc *readCounter) Read(p []byte) (n int, err error) {
n, err = rc.r.Read(p)
rc.c += int64(n)
return
}

12
plugin/differ.go Normal file
View File

@ -0,0 +1,12 @@
package plugin
import (
"github.com/containerd/containerd/mount"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"golang.org/x/net/context"
)
type Differ interface {
Apply(ctx context.Context, desc ocispec.Descriptor, mount []mount.Mount) (ocispec.Descriptor, error)
DiffMounts(ctx context.Context, lower, upper []mount.Mount, media, ref string) (ocispec.Descriptor, error)
}

2
plugin/plugin.go
View File

@ -19,6 +19,7 @@ const (
GRPCPlugin
SnapshotPlugin
TaskMonitorPlugin
DiffPlugin
)
type Registration struct {
@ -35,6 +36,7 @@ type InitContext struct {
Content content.Store
Meta *bolt.DB
Snapshotter snapshot.Snapshotter
Differ Differ
Config interface{}
Context context.Context
Monitor TaskMonitor

8
services/diff/client.go
View File

@ -54,6 +54,14 @@ func (r *remote) DiffMounts(ctx context.Context, a, b []mount.Mount, media, ref
return toDescriptor(resp.Diff), nil
}
func toDescriptor(d *descriptor.Descriptor) ocispec.Descriptor {
return ocispec.Descriptor{
MediaType: d.MediaType,
Digest: d.Digest,
Size: d.Size_,
}
}
func fromDescriptor(d ocispec.Descriptor) *descriptor.Descriptor {
return &descriptor.Descriptor{
MediaType: d.MediaType,

152
services/diff/service.go
View File

@ -1,22 +1,10 @@
package diff
import (
"io"
"io/ioutil"
"os"
diffapi "github.com/containerd/containerd/api/services/diff"
"github.com/containerd/containerd/api/types/descriptor"
mounttypes "github.com/containerd/containerd/api/types/mount"
"github.com/containerd/containerd/archive"
"github.com/containerd/containerd/archive/compression"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/mount"
"github.com/containerd/containerd/plugin"
"github.com/containerd/containerd/snapshot"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
"golang.org/x/net/context"
"google.golang.org/grpc"
)
@ -25,21 +13,15 @@ func init() {
plugin.Register("diff-grpc", &plugin.Registration{
Type: plugin.GRPCPlugin,
Init: func(ic *plugin.InitContext) (interface{}, error) {
return newService(ic.Content, ic.Snapshotter)
return &service{
diff: ic.Differ,
}, nil
},
})
}
type service struct {
store content.Store
snapshotter snapshot.Snapshotter
}
func newService(store content.Store, snapshotter snapshot.Snapshotter) (*service, error) {
return &service{
store: store,
snapshotter: snapshotter,
}, nil
diff plugin.Differ
}
func (s *service) Register(gs *grpc.Server) error {
@ -53,143 +35,31 @@ func (s *service) Apply(ctx context.Context, er *diffapi.ApplyRequest) (*diffapi
mounts := toMounts(er.Mounts)
dir, err := ioutil.TempDir("", "extract-")
if err != nil {
return nil, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(dir)
if err := mount.MountAll(mounts, dir); err != nil {
return nil, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(dir, 0)
r, err := s.store.Reader(ctx, desc.Digest)
if err != nil {
return nil, errors.Wrap(err, "failed to get reader from content store")
}
defer r.Close()
// TODO: only decompress stream if media type is compressed
ds, err := compression.DecompressStream(r)
ocidesc, err := s.diff.Apply(ctx, desc, mounts)
if err != nil {
return nil, err
}
defer ds.Close()
digester := digest.Canonical.Digester()
rc := &readCounter{
r: io.TeeReader(ds, digester.Hash()),
}
return &diffapi.ApplyResponse{
Applied: fromDescriptor(ocidesc),
}, nil
if _, err := archive.Apply(ctx, dir, rc); err != nil {
return nil, err
}
// Read any trailing data
if _, err := io.Copy(ioutil.Discard, rc); err != nil {
return nil, err
}
resp := &diffapi.ApplyResponse{
Applied: &descriptor.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Digest: digester.Digest(),
Size_: rc.c,
},
}
return resp, nil
}
func (s *service) Diff(ctx context.Context, dr *diffapi.DiffRequest) (*diffapi.DiffResponse, error) {
aMounts := toMounts(dr.Left)
bMounts := toMounts(dr.Right)
aDir, err := ioutil.TempDir("", "left-")
ocidesc, err := s.diff.DiffMounts(ctx, aMounts, bMounts, dr.MediaType, dr.Ref)
if err != nil {
return nil, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(aDir)
bDir, err := ioutil.TempDir("", "right-")
if err != nil {
return nil, errors.Wrap(err, "failed to create temporary directory")
}
defer os.RemoveAll(bDir)
if err := mount.MountAll(aMounts, aDir); err != nil {
return nil, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(aDir, 0)
if err := mount.MountAll(bMounts, bDir); err != nil {
return nil, errors.Wrap(err, "failed to mount")
}
defer mount.Unmount(bDir, 0)
cw, err := s.store.Writer(ctx, dr.Ref, 0, "")
if err != nil {
return nil, errors.Wrap(err, "failed to open writer")
}
// TODO: Validate media type
// TODO: Support compressed media types (link compressed to uncompressed)
//dgstr := digest.SHA256.Digester()
//wc := &writeCounter{}
//compressed, err := compression.CompressStream(cw, compression.Gzip)
//if err != nil {
// return nil, errors.Wrap(err, "failed to get compressed stream")
//}
//err = archive.WriteDiff(ctx, io.MultiWriter(compressed, dgstr.Hash(), wc), lowerDir, upperDir)
//compressed.Close()
err = archive.WriteDiff(ctx, cw, aDir, bDir)
if err != nil {
return nil, errors.Wrap(err, "failed to write diff")
}
dgst := cw.Digest()
if err := cw.Commit(0, dgst); err != nil {
return nil, errors.Wrap(err, "failed to commit")
}
info, err := s.store.Info(ctx, dgst)
if err != nil {
return nil, errors.Wrap(err, "failed to get info from content store")
}
desc := ocispec.Descriptor{
MediaType: dr.MediaType,
Digest: info.Digest,
Size: info.Size,
return nil, err
}
return &diffapi.DiffResponse{
Diff: fromDescriptor(desc),
Diff: fromDescriptor(ocidesc),
}, nil
}
type readCounter struct {
r io.Reader
c int64
}
func (rc *readCounter) Read(p []byte) (n int, err error) {
n, err = rc.r.Read(p)
rc.c += int64(n)
return
}
func toDescriptor(d *descriptor.Descriptor) ocispec.Descriptor {
return ocispec.Descriptor{
MediaType: d.MediaType,
Digest: d.Digest,
Size: d.Size_,
}
}
func toMounts(apim []*mounttypes.Mount) []mount.Mount {
mounts := make([]mount.Mount, len(apim))
for i, m := range apim {