services/content: move service client into package

Signed-off-by: Stephen J Day <stephen.day@docker.com>

cmd/dist/get.go

@@ -5,7 +5,7 @@ import (
 	"os"
 
 	contentapi "github.com/docker/containerd/api/services/content"
-	"github.com/docker/containerd/content"
+	contentservice "github.com/docker/containerd/services/content"
 	digest "github.com/opencontainers/go-digest"
 	"github.com/urfave/cli"
 )
@@ -33,7 +33,7 @@ Output paths can be used to directly access blobs on disk.`,
 			return err
 		}
 
-		cs := content.NewProviderFromClient(contentapi.NewContentClient(conn))
+		cs := contentservice.NewProviderFromClient(contentapi.NewContentClient(conn))
 
 		rc, err := cs.Reader(ctx, dgst)
 		if err != nil {

cmd/dist/ingest.go

@@ -6,9 +6,10 @@ import (
 
 	contentapi "github.com/docker/containerd/api/services/content"
 	"github.com/docker/containerd/content"
+	contentservice "github.com/docker/containerd/services/content"
 	"github.com/opencontainers/go-digest"
-	"github.com/urfave/cli"
 	"github.com/pkg/errors"
+	"github.com/urfave/cli"
 )
 
 var ingestCommand = cli.Command{
@@ -51,7 +52,7 @@ var ingestCommand = cli.Command{
 			return errors.New("must specify a transaction reference")
 		}
 
-		ingester := content.NewIngesterFromClient(contentapi.NewContentClient(conn))
+		ingester := contentservice.NewIngesterFromClient(contentapi.NewContentClient(conn))
 
 		// TODO(stevvooe): Allow ingest to be reentrant. Currently, we expect
 		// all data to be written in a single invocation. Allow multiple writes

content/content.go

@@ -11,10 +11,17 @@ import (
 )
 
 var (
-	errNotFound = errors.New("content: not found")
+	// ErrNotFound is returned when an item is not found.
-	errExists   = errors.New("content: exists")
+	//
+	// Use IsNotFound(err) to detect this condition.
+	ErrNotFound = errors.New("content: not found")
 
-	BufPool = sync.Pool{
+	// ErrExists is returned when something exists when it may not be expected.
+	//
+	// Use IsExists(err) to detect this condition.
+	ErrExists = errors.New("content: exists")
+
+	bufPool = sync.Pool{
 		New: func() interface{} {
 			return make([]byte, 1<<20)
 		},
@@ -52,9 +59,9 @@ type Ingester interface {
 }
 
 func IsNotFound(err error) bool {
-	return errors.Cause(err) == errNotFound
+	return errors.Cause(err) == ErrNotFound
 }
 
 func IsExists(err error) bool {
-	return errors.Cause(err) == errExists
+	return errors.Cause(err) == ErrExists
 }

content/helpers.go

@@ -47,8 +47,8 @@ func WriteBlob(ctx context.Context, cs Ingester, ref string, r io.Reader, size i
 		}
 	}
 
-	buf := BufPool.Get().([]byte)
+	buf := bufPool.Get().([]byte)
-	defer BufPool.Put(buf)
+	defer bufPool.Put(buf)
 
 	if _, err := io.CopyBuffer(cw, r, buf); err != nil {
 		return err

content/store.go

@@ -41,7 +41,7 @@ func (s *Store) Info(dgst digest.Digest) (Info, error) {
 	fi, err := os.Stat(p)
 	if err != nil {
 		if os.IsNotExist(err) {
-			err = errNotFound
+			err = ErrNotFound
 		}
 
 		return Info{}, err
@@ -63,7 +63,7 @@ func (s *Store) Reader(ctx context.Context, dgst digest.Digest) (io.ReadCloser,
 	fp, err := os.Open(s.blobPath(dgst))
 	if err != nil {
 		if os.IsNotExist(err) {
-			err = errNotFound
+			err = ErrNotFound
 		}
 		return nil, err
 	}
@@ -81,7 +81,7 @@ func (cs *Store) Delete(dgst digest.Digest) error {
 			return err
 		}
 
-		return errNotFound
+		return ErrNotFound
 	}
 
 	return nil
@@ -243,8 +243,8 @@ func (s *Store) Writer(ctx context.Context, ref string, total int64, expected di
 		}
 		defer fp.Close()
 
-		p := BufPool.Get().([]byte)
+		p := bufPool.Get().([]byte)
-		defer BufPool.Put(p)
+		defer bufPool.Put(p)
 
 		offset, err = io.CopyBuffer(digester.Hash(), fp, p)
 		if err != nil {

content/writer.go

@@ -102,7 +102,7 @@ func (w *writer) Commit(size int64, expected digest.Digest) error {
 	if err := os.Rename(ingest, target); err != nil {
 		if os.IsExist(err) {
 			// collision with the target file!
-			return errExists
+			return ErrExists
 		}
 		return err
 	}

services/content/helpers.go

@@ -0,0 +1,19 @@
+package content
+
+import (
+	"github.com/docker/containerd/content"
+	"github.com/pkg/errors"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+)
+
+func rewriteGRPCError(err error) error {
+	switch grpc.Code(errors.Cause(err)) {
+	case codes.AlreadyExists:
+		return content.ErrExists
+	case codes.NotFound:
+		return content.ErrNotFound
+	}
+
+	return err
+}

services/content/ingester.go

@@ -4,79 +4,14 @@ import (
 	"context"
 	"io"
 
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/codes"
-
 	contentapi "github.com/docker/containerd/api/services/content"
+	"github.com/docker/containerd/content"
+
 	digest "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 )
 
-func NewProviderFromClient(client contentapi.ContentClient) Provider {
+func NewIngesterFromClient(client contentapi.ContentClient) content.Ingester {
-	return &remoteProvider{
-		client: client,
-	}
-}
-
-type remoteProvider struct {
-	client contentapi.ContentClient
-}
-
-func (rp *remoteProvider) Reader(ctx context.Context, dgst digest.Digest) (io.ReadCloser, error) {
-	client, err := rp.client.Read(ctx, &contentapi.ReadRequest{Digest: dgst})
-	if err != nil {
-		return nil, err
-	}
-
-	return &remoteReader{
-		client: client,
-	}, nil
-}
-
-type remoteReader struct {
-	client contentapi.Content_ReadClient
-	extra  []byte
-}
-
-func (rr *remoteReader) Read(p []byte) (n int, err error) {
-	n += copy(p, rr.extra)
-	if n >= len(p) {
-		if n <= len(rr.extra) {
-			rr.extra = rr.extra[n:]
-		} else {
-			rr.extra = rr.extra[:0]
-		}
-		return
-	}
-
-	p = p[n:]
-	for len(p) > 0 {
-		var resp *contentapi.ReadResponse
-		// fill our buffer up until we can fill p.
-		resp, err = rr.client.Recv()
-		if err != nil {
-			return
-		}
-
-		copied := copy(p, resp.Data)
-		n += copied
-		p = p[copied:]
-
-		if copied < len(p) {
-			continue
-		}
-
-		rr.extra = append(rr.extra, resp.Data[copied:]...)
-	}
-
-	return
-}
-
-func (rr *remoteReader) Close() error {
-	return rr.client.CloseSend()
-}
-
-func NewIngesterFromClient(client contentapi.ContentClient) Ingester {
 	return &remoteIngester{
 		client: client,
 	}
@@ -86,7 +21,7 @@ type remoteIngester struct {
 	client contentapi.ContentClient
 }
 
-func (ri *remoteIngester) Writer(ctx context.Context, ref string, size int64, expected digest.Digest) (Writer, error) {
+func (ri *remoteIngester) Writer(ctx context.Context, ref string, size int64, expected digest.Digest) (content.Writer, error) {
 	wrclient, offset, err := ri.negotiate(ctx, ref, size, expected)
 	if err != nil {
 		return nil, rewriteGRPCError(err)
@@ -154,15 +89,15 @@ func (rw *remoteWriter) send(req *contentapi.WriteRequest) (*contentapi.WriteRes
 	return resp, err
 }
 
-func (rw *remoteWriter) Status() (Status, error) {
+func (rw *remoteWriter) Status() (content.Status, error) {
 	resp, err := rw.send(&contentapi.WriteRequest{
 		Action: contentapi.WriteActionStat,
 	})
 	if err != nil {
-		return Status{}, err
+		return content.Status{}, err
 	}
 
-	return Status{
+	return content.Status{
 		Ref:       rw.ref,
 		Offset:    resp.Offset,
 		StartedAt: resp.StartedAt,
@@ -226,14 +161,3 @@ func (rw *remoteWriter) Truncate(size int64) error {
 func (rw *remoteWriter) Close() error {
 	return rw.client.CloseSend()
 }
-
-func rewriteGRPCError(err error) error {
-	switch grpc.Code(errors.Cause(err)) {
-	case codes.AlreadyExists:
-		return errExists
-	case codes.NotFound:
-		return errNotFound
-	}
-
-	return err
-}

services/content/provider.go

@@ -0,0 +1,76 @@
+package content
+
+import (
+	"context"
+	"io"
+
+	contentapi "github.com/docker/containerd/api/services/content"
+	"github.com/docker/containerd/content"
+	digest "github.com/opencontainers/go-digest"
+)
+
+func NewProviderFromClient(client contentapi.ContentClient) content.Provider {
+	return &remoteProvider{
+		client: client,
+	}
+}
+
+type remoteProvider struct {
+	client contentapi.ContentClient
+}
+
+func (rp *remoteProvider) Reader(ctx context.Context, dgst digest.Digest) (io.ReadCloser, error) {
+	client, err := rp.client.Read(ctx, &contentapi.ReadRequest{Digest: dgst})
+	if err != nil {
+		return nil, err
+	}
+
+	return &remoteReader{
+		client: client,
+	}, nil
+}
+
+type remoteReader struct {
+	client contentapi.Content_ReadClient
+	extra  []byte
+}
+
+func (rr *remoteReader) Read(p []byte) (n int, err error) {
+	n += copy(p, rr.extra)
+	if n >= len(p) {
+		if n <= len(rr.extra) {
+			rr.extra = rr.extra[n:]
+		} else {
+			rr.extra = rr.extra[:0]
+		}
+		return
+	}
+
+	p = p[n:]
+	for len(p) > 0 {
+		var resp *contentapi.ReadResponse
+		// fill our buffer up until we can fill p.
+		resp, err = rr.client.Recv()
+		if err != nil {
+			return
+		}
+
+		copied := copy(p, resp.Data)
+		n += copied
+		p = p[copied:]
+
+		if copied < len(p) {
+			continue
+		}
+
+		rr.extra = append(rr.extra, resp.Data[copied:]...)
+	}
+
+	return
+}
+
+// TODO(stevvooe): Implemente io.ReaderAt.
+
+func (rr *remoteReader) Close() error {
+	return rr.client.CloseSend()
+}

services/content/service.go

@@ -2,6 +2,7 @@ package content
 
 import (
 	"io"
+	"sync"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/docker/containerd"
@@ -20,6 +21,12 @@ type Service struct {
 	store *content.Store
 }
 
+var bufPool = sync.Pool{
+	New: func() interface{} {
+		return make([]byte, 1<<20)
+	},
+}
+
 var _ api.ContentServer = &Service{}
 
 func init() {
@@ -100,9 +107,9 @@ func (s *Service) Read(req *api.ReadRequest, session api.Content_ReadServer) err
 
 		// TODO(stevvooe): Using the global buffer pool. At 32KB, it is probably
 		// little inefficient for work over a fast network. We can tune this later.
-		p = content.BufPool.Get().([]byte)
+		p = bufPool.Get().([]byte)
 	)
-	defer content.BufPool.Put(p)
+	defer bufPool.Put(p)
 
 	if offset < 0 {
 		offset = 0