containerd/diff/apply/apply.go
Michael Crosby 97a98773cf Add StreamProcessor for apply
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2019-08-07 18:35:55 +00:00

122 lines
3.2 KiB
Go

/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package apply
import (
"context"
"io"
"io/ioutil"
"time"
"github.com/containerd/containerd/archive"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/diff"
"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.Provider) diff.Applier {
return &fsApplier{
store: cs,
}
}
type fsApplier struct {
store content.Provider
}
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, opts ...diff.ApplyOpt) (d ocispec.Descriptor, err error) {
t1 := time.Now()
defer func() {
if err == nil {
log.G(ctx).WithFields(logrus.Fields{
"d": time.Since(t1),
"dgst": desc.Digest,
"size": desc.Size,
"media": desc.MediaType,
}).Debugf("diff applied")
}
}()
var config diff.ApplyConfig
for _, o := range opts {
if err := o(&config); err != nil {
return emptyDesc, errors.Wrap(err, "failed to apply config opt")
}
}
ra, err := s.store.ReaderAt(ctx, desc)
if err != nil {
return emptyDesc, errors.Wrap(err, "failed to get reader from content store")
}
defer ra.Close()
processor := diff.NewProcessorChain(desc.MediaType, content.NewReader(ra))
for {
if processor, err = diff.GetProcessor(ctx, desc.MediaType, processor, config.ProcessorPayloads); err != nil {
return emptyDesc, errors.Wrapf(err, "failed to get stream processor for %s", desc.MediaType)
}
if processor.MediaType() == ocispec.MediaTypeImageLayer {
break
}
}
defer processor.Close()
digester := digest.Canonical.Digester()
rc := &readCounter{
r: io.TeeReader(processor, digester.Hash()),
}
if err := mount.WithTempMount(ctx, mounts, func(root string) error {
if _, err := archive.Apply(ctx, root, rc); err != nil {
return err
}
// Read any trailing data
_, err := io.Copy(ioutil.Discard, rc)
return err
}); err != nil {
return emptyDesc, err
}
return ocispec.Descriptor{
MediaType: ocispec.MediaTypeImageLayer,
Size: rc.c,
Digest: digester.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
}