Integrate context with storage package

This changeset integrates context with the storage package. Debug messages have
been added to exported methods. Existing log messages will now include
contextual details through logger fields to aid in debugging. This integration
focuses on logging and may be followed up with a metric-oriented change in the
future.

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

storage/blobstore.go

@@ -3,10 +3,10 @@ package storage
 import (
 	"fmt"
 
-	"github.com/Sirupsen/logrus"
-
+	ctxu "github.com/docker/distribution/context"
 	"github.com/docker/distribution/digest"
 	"github.com/docker/distribution/storagedriver"
+	"golang.org/x/net/context"
 )
 
 // TODO(stevvooe): Currently, the blobStore implementation used by the
@@ -19,6 +19,7 @@ import (
 // backend links.
 type blobStore struct {
 	*registry
+	ctx context.Context
 }
 
 // exists reports whether or not the path exists. If the driver returns error
@@ -110,7 +111,7 @@ func (bs *blobStore) resolve(path string) (string, error) {
 func (bs *blobStore) put(p []byte) (digest.Digest, error) {
 	dgst, err := digest.FromBytes(p)
 	if err != nil {
-		logrus.Errorf("error digesting content: %v, %s", err, string(p))
+		ctxu.GetLogger(bs.ctx).Errorf("error digesting content: %v, %s", err, string(p))
 		return "", err
 	}