098ff94b24
Remove rootfs service in place of snapshot service. Adds diff service for extracting and creating diffs. Diff creation is not yet implemented. This service allows pulling or creating images without needing root access to mount. Additionally in the future this will allow containerd to ensure extractions happen safely in a chroot if needed. Signed-off-by: Derek McGowan <derek@mcgstyle.net>
139 lines
3.2 KiB
Go
139 lines
3.2 KiB
Go
package diff
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import (
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"io"
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"io/ioutil"
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"os"
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"github.com/containerd/containerd"
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diffapi "github.com/containerd/containerd/api/services/diff"
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"github.com/containerd/containerd/api/types/descriptor"
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mounttypes "github.com/containerd/containerd/api/types/mount"
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"github.com/containerd/containerd/archive"
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"github.com/containerd/containerd/archive/compression"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/plugin"
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"github.com/containerd/containerd/snapshot"
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digest "github.com/opencontainers/go-digest"
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ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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"github.com/pkg/errors"
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"golang.org/x/net/context"
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"google.golang.org/grpc"
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)
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func init() {
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plugin.Register("diff-grpc", &plugin.Registration{
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Type: plugin.GRPCPlugin,
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Init: func(ic *plugin.InitContext) (interface{}, error) {
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return newService(ic.Content, ic.Snapshotter)
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},
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})
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}
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type service struct {
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store content.Store
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snapshotter snapshot.Snapshotter
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}
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func newService(store content.Store, snapshotter snapshot.Snapshotter) (*service, error) {
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return &service{
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store: store,
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snapshotter: snapshotter,
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}, nil
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}
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func (s *service) Register(gs *grpc.Server) error {
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diffapi.RegisterDiffServer(gs, s)
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return nil
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}
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func (s *service) Apply(ctx context.Context, er *diffapi.ApplyRequest) (*diffapi.ApplyResponse, error) {
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desc := toDescriptor(er.Diff)
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// TODO: Check for supported media types
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mounts := toMounts(er.Mounts)
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dir, err := ioutil.TempDir("", "extract-")
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if err != nil {
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return nil, errors.Wrap(err, "failed to create temporary directory")
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}
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defer os.RemoveAll(dir)
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if err := containerd.MountAll(mounts, dir); err != nil {
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return nil, errors.Wrap(err, "failed to mount")
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}
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defer containerd.Unmount(dir, 0)
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r, err := s.store.Reader(ctx, desc.Digest)
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if err != nil {
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return nil, errors.Wrap(err, "failed to get reader from content store")
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}
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defer r.Close()
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// TODO: only decompress stream if media type is compressed
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ds, err := compression.DecompressStream(r)
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if err != nil {
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return nil, err
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}
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defer ds.Close()
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digester := digest.Canonical.Digester()
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rc := &readCounter{
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r: io.TeeReader(ds, digester.Hash()),
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}
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if _, err := archive.Apply(ctx, dir, rc); err != nil {
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return nil, err
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}
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// Read any trailing data
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if _, err := io.Copy(ioutil.Discard, rc); err != nil {
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return nil, err
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}
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resp := &diffapi.ApplyResponse{
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Applied: &descriptor.Descriptor{
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MediaType: ocispec.MediaTypeImageLayer,
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Digest: digester.Digest(),
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Size_: rc.c,
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},
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}
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return resp, nil
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}
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func (s *service) Diff(context.Context, *diffapi.DiffRequest) (*diffapi.DiffResponse, error) {
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return nil, errors.New("not implemented")
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}
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type readCounter struct {
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r io.Reader
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c int64
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}
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func (rc *readCounter) Read(p []byte) (n int, err error) {
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n, err = rc.r.Read(p)
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rc.c += int64(n)
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return
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}
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func toDescriptor(d *descriptor.Descriptor) ocispec.Descriptor {
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return ocispec.Descriptor{
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MediaType: d.MediaType,
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Digest: d.Digest,
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Size: d.Size_,
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}
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}
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func toMounts(apim []*mounttypes.Mount) []containerd.Mount {
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mounts := make([]containerd.Mount, len(apim))
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for i, m := range apim {
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mounts[i] = containerd.Mount{
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Type: m.Type,
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Source: m.Source,
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Options: m.Options,
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}
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}
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return mounts
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}
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