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diff: rename differ to comparer

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Remove combined interface and split implementations.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
This commit is contained in:
Derek McGowan 2017-12-19 15:47:48 -08:00
parent b580441f91
commit b763777288
No known key found for this signature in database
GPG Key ID: F58C5D0A4405ACDB
12 changed files with 217 additions and 151 deletions
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3
client.go
View File

@ -24,7 +24,6 @@ import (
"github.com/containerd/containerd/containers"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/dialer"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/namespaces"
@ -458,7 +457,7 @@ func (c *Client) ImageService() images.Store {
}
// DiffService returns the underlying Differ
func (c *Client) DiffService() diff.DiffApplier {
func (c *Client) DiffService() DiffService {
return NewDiffServiceFromClient(diffapi.NewDiffClient(c.conn))
}

2
cmd/containerd/builtins.go
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@ -2,7 +2,7 @@ package main
// register containerd builtins here
import (
_ "github.com/containerd/containerd/diff/walking"
_ "github.com/containerd/containerd/diff/walking/plugin"
_ "github.com/containerd/containerd/gc/scheduler"
_ "github.com/containerd/containerd/services/containers"
_ "github.com/containerd/containerd/services/content"

4
cmd/ctr/commands/snapshots/snapshots.go
View File

@ -129,7 +129,7 @@ var diffCommand = cli.Command{
}
if idB == "" {
desc, err = rootfs.Diff(ctx, idA, snapshotter, client.DiffService(), opts...)
desc, err = rootfs.CreateDiff(ctx, idA, snapshotter, client.DiffService(), opts...)
if err != nil {
return err
}
@ -145,7 +145,7 @@ var diffCommand = cli.Command{
if err != nil {
return err
}
desc, err = ds.DiffMounts(ctx, a, b, opts...)
desc, err = ds.Compare(ctx, a, b, opts...)
if err != nil {
return err
}

13
diff.go
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@ -1,17 +1,24 @@
package containerd
import (
"context"
diffapi "github.com/containerd/containerd/api/services/diff/v1"
"github.com/containerd/containerd/api/types"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/mount"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"golang.org/x/net/context"
)
// DiffService handles the computation and application of diffs
type DiffService interface {
diff.Comparer
diff.Applier
}
// NewDiffServiceFromClient returns a new diff service which communicates
// over a GRPC connection.
func NewDiffServiceFromClient(client diffapi.DiffClient) diff.DiffApplier {
func NewDiffServiceFromClient(client diffapi.DiffClient) DiffService {
return &diffRemote{
client: client,
}
@ -33,7 +40,7 @@ func (r *diffRemote) Apply(ctx context.Context, diff ocispec.Descriptor, mounts
return toDescriptor(resp.Applied), nil
}
func (r *diffRemote) Diff(ctx context.Context, a, b []mount.Mount, opts ...diff.Opt) (ocispec.Descriptor, error) {
func (r *diffRemote) Compare(ctx context.Context, a, b []mount.Mount, opts ...diff.Opt) (ocispec.Descriptor, error) {
var config diff.Config
for _, opt := range opts {
if err := opt(&config); err != nil {

112
diff/apply/apply.go Normal file
View File

@ -0,0 +1,112 @@
package apply
import (
"context"
"io"
"io/ioutil"
"time"
"github.com/containerd/containerd/archive"
"github.com/containerd/containerd/archive/compression"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/mount"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// NewFileSystemApplier returns an applier which simply mounts
// and applies diff onto the mounted filesystem.
func NewFileSystemApplier(cs content.Store) diff.Applier {
return &fsApplier{
store: cs,
}
}
type fsApplier struct {
store content.Store
}
var emptyDesc = ocispec.Descriptor{}
// Apply applies the content associated with the provided digests onto the
// provided mounts. Archive content will be extracted and decompressed if
// necessary.
func (s *fsApplier) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount) (d ocispec.Descriptor, err error) {
t1 := time.Now()
defer func() {
if err == nil {
log.G(ctx).WithFields(logrus.Fields{
"d": time.Now().Sub(t1),
"dgst": desc.Digest,
"size": desc.Size,
"media": desc.MediaType,
}).Debugf("diff applied")
}
}()
isCompressed, err := images.IsCompressedDiff(ctx, desc.MediaType)
if err != nil {
return emptyDesc, errors.Wrapf(errdefs.ErrNotImplemented, "unsupported diff media type: %v", desc.MediaType)
}
var ocidesc ocispec.Descriptor
if err := mount.WithTempMount(ctx, mounts, func(root string) error {
ra, err := s.store.ReaderAt(ctx, desc.Digest)
if err != nil {
return errors.Wrap(err, "failed to get reader from content store")
}
defer ra.Close()
r := content.NewReader(ra)
if isCompressed {
ds, err := compression.DecompressStream(r)
if err != nil {
return err
}
defer ds.Close()
r = ds
}
digester := digest.Canonical.Digester()
rc := &readCounter{
r: io.TeeReader(r, digester.Hash()),
}
if _, err := archive.Apply(ctx, root, rc); err != nil {
return err
}
// Read any trailing data
if _, err := io.Copy(ioutil.Discard, rc); err != nil {
return err
}
ocidesc = ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Size: rc.c,
Digest: digester.Digest(),
}
return nil
}); err != nil {
return emptyDesc, err
}
return 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
}

20
diff/diff.go
View File

@ -1,9 +1,10 @@
package diff
import (
"context"
"github.com/containerd/containerd/mount"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"golang.org/x/net/context"
)
// Config is used to hold parameters needed for a diff operation
@ -24,14 +25,14 @@ type Config struct {
// Opt is used to configure a diff operation
type Opt func(*Config) error
// Differ allows creation of filesystem diffs between mounts
type Differ interface {
// Diff computes the difference between two mounts and returns a
// Comparer allows creation of filesystem diffs between mounts
type Comparer interface {
// Compare computes the difference between two mounts and returns a
// descriptor for the computed diff. The options can provide
// a ref which can be used to track the content creation of the diff.
// The media type which is used to determine the format of the created
// content can also be provided as an option.
Diff(ctx context.Context, lower, upper []mount.Mount, opts ...Opt) (ocispec.Descriptor, error)
Compare(ctx context.Context, lower, upper []mount.Mount, opts ...Opt) (ocispec.Descriptor, error)
}
// Applier allows applying diffs between mounts
@ -44,15 +45,6 @@ type Applier interface {
Apply(ctx context.Context, desc ocispec.Descriptor, mount []mount.Mount) (ocispec.Descriptor, error)
}
// DiffApplier is the interface that groups the basic Apply and Diff methods.
//
// golint says `type name will be used as diff.DiffApplier by other packages, and that stutters`,
// but that can be ignored now.
type DiffApplier interface { // nolint: golint
Applier
Differ
}
// WithMediaType sets the media type to use for creating the diff, without
// specifying the differ will choose a default.
func WithMediaType(m string) Opt {

120
diff/walking/differ.go
View File

@ -1,11 +1,11 @@
package walking
import (
"context"
"crypto/rand"
"encoding/base64"
"fmt"
"io"
"io/ioutil"
"time"
"github.com/containerd/containerd/archive"
@ -13,121 +13,34 @@ import (
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/metadata"
"github.com/containerd/containerd/mount"
"github.com/containerd/containerd/platforms"
"github.com/containerd/containerd/plugin"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
func init() {
plugin.Register(&plugin.Registration{
Type: plugin.DiffPlugin,
ID: "walking",
Requires: []plugin.Type{
plugin.MetadataPlugin,
},
InitFn: func(ic *plugin.InitContext) (interface{}, error) {
md, err := ic.Get(plugin.MetadataPlugin)
if err != nil {
return nil, err
}
ic.Meta.Platforms = append(ic.Meta.Platforms, platforms.DefaultSpec())
return NewWalkingDiff(md.(*metadata.DB).ContentStore())
},
})
}
type walkingDiff struct {
store content.Store
}
var emptyDesc = ocispec.Descriptor{}
// NewWalkingDiff is a generic implementation of diff.DiffApplier.
// NewWalkingDiff is expected to work with any filesystem.
func NewWalkingDiff(store content.Store) (diff.DiffApplier, error) {
// NewWalkingDiff is a generic implementation of diff.Comparer. The diff is
// calculated by mounting both the upper and lower mount sets and walking the
// mounted directories concurrently. Changes are calculated by comparing files
// against each other or by comparing file existence between directories.
// NewWalkingDiff uses no special characteristics of the mount sets and is
// expected to work with any filesystem.
func NewWalkingDiff(store content.Store) diff.Comparer {
return &walkingDiff{
store: store,
}, nil
}
}
// Apply applies the content associated with the provided digests onto the
// provided mounts. Archive content will be extracted and decompressed if
// necessary.
func (s *walkingDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount) (d ocispec.Descriptor, err error) {
t1 := time.Now()
defer func() {
if err == nil {
log.G(ctx).WithFields(logrus.Fields{
"d": time.Now().Sub(t1),
"dgst": desc.Digest,
"size": desc.Size,
"media": desc.MediaType,
}).Debugf("diff applied")
}
}()
isCompressed, err := images.IsCompressedDiff(ctx, desc.MediaType)
if err != nil {
return emptyDesc, errors.Wrapf(errdefs.ErrNotImplemented, "unsupported diff media type: %v", desc.MediaType)
}
var ocidesc ocispec.Descriptor
if err := mount.WithTempMount(ctx, mounts, func(root string) error {
ra, err := s.store.ReaderAt(ctx, desc.Digest)
if err != nil {
return errors.Wrap(err, "failed to get reader from content store")
}
defer ra.Close()
r := content.NewReader(ra)
if isCompressed {
ds, err := compression.DecompressStream(r)
if err != nil {
return err
}
defer ds.Close()
r = ds
}
digester := digest.Canonical.Digester()
rc := &readCounter{
r: io.TeeReader(r, digester.Hash()),
}
if _, err := archive.Apply(ctx, root, rc); err != nil {
return err
}
// Read any trailing data
if _, err := io.Copy(ioutil.Discard, rc); err != nil {
return err
}
ocidesc = ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Size: rc.c,
Digest: digester.Digest(),
}
return nil
}); err != nil {
return emptyDesc, err
}
return ocidesc, nil
}
// Diff creates a diff between the given mounts and uploads the result
// Compare creates a diff between the given mounts and uploads the result
// to the content store.
func (s *walkingDiff) Diff(ctx context.Context, lower, upper []mount.Mount, opts ...diff.Opt) (d ocispec.Descriptor, err error) {
func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, opts ...diff.Opt) (d ocispec.Descriptor, err error) {
var config diff.Config
for _, opt := range opts {
if err := opt(&config); err != nil {
@ -228,17 +141,6 @@ func (s *walkingDiff) Diff(ctx context.Context, lower, upper []mount.Mount, opts
return 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 uniqueRef() string {
t := time.Now()
var b [3]byte

39
diff/walking/plugin/plugin.go Normal file
View File

@ -0,0 +1,39 @@
package plugin
import (
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/diff/apply"
"github.com/containerd/containerd/diff/walking"
"github.com/containerd/containerd/metadata"
"github.com/containerd/containerd/platforms"
"github.com/containerd/containerd/plugin"
)
func init() {
plugin.Register(&plugin.Registration{
Type: plugin.DiffPlugin,
ID: "walking",
Requires: []plugin.Type{
plugin.MetadataPlugin,
},
InitFn: func(ic *plugin.InitContext) (interface{}, error) {
md, err := ic.Get(plugin.MetadataPlugin)
if err != nil {
return nil, err
}
ic.Meta.Platforms = append(ic.Meta.Platforms, platforms.DefaultSpec())
cs := md.(*metadata.DB).ContentStore()
return diffPlugin{
Comparer: walking.NewWalkingDiff(cs),
Applier: apply.NewFileSystemApplier(cs),
}, nil
},
})
}
type diffPlugin struct {
diff.Comparer
diff.Applier
}

24
diff/windows/windows.go
View File

@ -3,6 +3,7 @@
package windows
import (
"context"
"io"
"io/ioutil"
"time"
@ -23,7 +24,6 @@ import (
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
func init() {
@ -45,15 +45,25 @@ func init() {
})
}
// CompareApplier handles both comparision and
// application of layer diffs.
type CompareApplier interface {
diff.Applier
diff.Comparer
}
// windowsDiff does filesystem comparison and application
// for Windows specific layer diffs.
type windowsDiff struct {
store content.Store
}
var emptyDesc = ocispec.Descriptor{}
// NewWindowsDiff is the Windows container layer implementation of diff.Differ.
func NewWindowsDiff(store content.Store) (diff.Differ, error) {
return &windowsDiff{
// NewWindowsDiff is the Windows container layer implementation
// for comparing and applying filesystem layers
func NewWindowsDiff(store content.Store) (CompareApplier, error) {
return windowsDiff{
store: store,
}, nil
}
@ -61,7 +71,7 @@ func NewWindowsDiff(store content.Store) (diff.Differ, error) {
// Apply applies the content associated with the provided digests onto the
// provided mounts. Archive content will be extracted and decompressed if
// necessary.
func (s *windowsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount) (d ocispec.Descriptor, err error) {
func (s windowsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts []mount.Mount) (d ocispec.Descriptor, err error) {
t1 := time.Now()
defer func() {
if err == nil {
@ -128,9 +138,9 @@ func (s *windowsDiff) Apply(ctx context.Context, desc ocispec.Descriptor, mounts
}, nil
}
// DiffMounts creates a diff between the given mounts and uploads the result
// Compare creates a diff between the given mounts and uploads the result
// to the content store.
func (s *windowsDiff) DiffMounts(ctx context.Context, lower, upper []mount.Mount, opts ...diff.Opt) (d ocispec.Descriptor, err error) {
func (s windowsDiff) Compare(ctx context.Context, lower, upper []mount.Mount, opts ...diff.Opt) (d ocispec.Descriptor, err error) {
return emptyDesc, errdefs.ErrNotImplemented
}

10
rootfs/diff.go
View File

@ -10,11 +10,11 @@ import (
"golang.org/x/net/context"
)
// Diff creates a layer diff for the given snapshot identifier from the parent
// of the snapshot. A content ref is provided to track the progress of the
// content creation and the provided snapshotter and mount differ are used
// CreateDiff creates a layer diff for the given snapshot identifier from the
// parent of the snapshot. A content ref is provided to track the progress of
// the content creation and the provided snapshotter and mount differ are used
// for calculating the diff. The descriptor for the layer diff is returned.
func Diff(ctx context.Context, snapshotID string, sn snapshots.Snapshotter, d diff.Differ, opts ...diff.Opt) (ocispec.Descriptor, error) {
func CreateDiff(ctx context.Context, snapshotID string, sn snapshots.Snapshotter, d diff.Comparer, opts ...diff.Opt) (ocispec.Descriptor, error) {
info, err := sn.Stat(ctx, snapshotID)
if err != nil {
return ocispec.Descriptor{}, err
@ -42,5 +42,5 @@ func Diff(ctx context.Context, snapshotID string, sn snapshots.Snapshotter, d di
defer sn.Remove(ctx, upperKey)
}
return d.Diff(ctx, lower, upper, opts...)
return d.Compare(ctx, lower, upper, opts...)
}

19
services/diff/service.go
View File

@ -23,6 +23,11 @@ type config struct {
Order []string `toml:"default"`
}
type differ interface {
diff.Comparer
diff.Applier
}
func init() {
plugin.Register(&plugin.Registration{
Type: plugin.GRPCPlugin,
@ -38,20 +43,20 @@ func init() {
}
orderedNames := ic.Config.(*config).Order
ordered := make([]diff.DiffApplier, len(orderedNames))
ordered := make([]differ, len(orderedNames))
for i, n := range orderedNames {
differp, ok := differs[n]
if !ok {
return nil, errors.Errorf("needed differ not loaded: %s", n)
}
differ, err := differp.Instance()
d, err := differp.Instance()
if err != nil {
return nil, errors.Wrapf(err, "could not load required differ due plugin init error: %s", n)
}
ordered[i], ok = differ.(diff.DiffApplier)
ordered[i], ok = d.(differ)
if !ok {
return nil, errors.Errorf("differ does not implement diff.DiffApplier interface: %s", n)
return nil, errors.Errorf("differ does not implement Comparer and Applier interface: %s", n)
}
}
@ -63,7 +68,7 @@ func init() {
}
type service struct {
differs []diff.DiffApplier
differs []differ
}
func (s *service) Register(gs *grpc.Server) error {
@ -115,8 +120,8 @@ func (s *service) Diff(ctx context.Context, dr *diffapi.DiffRequest) (*diffapi.D
opts = append(opts, diff.WithLabels(dr.Labels))
}
for _, differ := range s.differs {
ocidesc, err = differ.Diff(ctx, aMounts, bMounts, opts...)
for _, d := range s.differs {
ocidesc, err = d.Compare(ctx, aMounts, bMounts, opts...)
if !errdefs.IsNotImplemented(err) {
break
}

2
task.go
View File

@ -536,7 +536,7 @@ func (t *task) checkpointRWSnapshot(ctx context.Context, index *v1.Index, snapsh
opts := []diff.Opt{
diff.WithReference(fmt.Sprintf("checkpoint-rw-%s", id)),
}
rw, err := rootfs.Diff(ctx, id, t.client.SnapshotService(snapshotterName), t.client.DiffService(), opts...)
rw, err := rootfs.CreateDiff(ctx, id, t.client.SnapshotService(snapshotterName), t.client.DiffService(), opts...)
if err != nil {
return err
}