Merge pull request #992 from estesp/errrbody-likes-errrrors

Use error interfaces for content/metadata

content/content.go

@@ -7,26 +7,9 @@ import (
 	"time"
 
 	"github.com/opencontainers/go-digest"
-	"github.com/pkg/errors"
 )
 
 var (
-	// ErrNotFound is returned when an item is not found.
-	//
-	// Use IsNotFound(err) to detect this condition.
-	ErrNotFound = errors.New("content: not found")
-
-	// ErrExists is returned when something exists when it may not be expected.
-	//
-	// Use IsExists(err) to detect this condition.
-	ErrExists = errors.New("content: exists")
-
-	// ErrLocked is returned when content is actively being uploaded, this
-	// indicates that another process is attempting to upload the same content.
-	//
-	// Use IsLocked(err) to detect this condition.
-	ErrLocked = errors.New("content: locked")
-
 	bufPool = sync.Pool{
 		New: func() interface{} {
 			return make([]byte, 1<<20)
@@ -106,15 +89,3 @@ type Store interface {
 	Ingester
 	Provider
 }
-
-func IsNotFound(err error) bool {
-	return errors.Cause(err) == ErrNotFound
-}
-
-func IsExists(err error) bool {
-	return errors.Cause(err) == ErrExists
-}
-
-func IsLocked(err error) bool {
-	return errors.Cause(err) == ErrLocked
-}

content/errors.go

@@ -0,0 +1,120 @@
+package content
+
+type contentExistsErr struct {
+	desc string
+}
+
+type contentNotFoundErr struct {
+	desc string
+}
+
+type contentLockedErr struct {
+	desc string
+}
+
+// ErrExists is returned when something exists when it may not be expected.
+func ErrExists(msg string) error {
+	if msg == "" {
+		msg = "content: exists"
+	}
+	return contentExistsErr{
+		desc: msg,
+	}
+}
+
+// ErrNotFound is returned when an item is not found.
+func ErrNotFound(msg string) error {
+	if msg == "" {
+		msg = "content: not found"
+	}
+	return contentNotFoundErr{
+		desc: msg,
+	}
+}
+
+// ErrLocked is returned when content is actively being uploaded, this
+// indicates that another process is attempting to upload the same content.
+func ErrLocked(msg string) error {
+	if msg == "" {
+		msg = "content: locked"
+	}
+	return contentLockedErr{
+		desc: msg,
+	}
+}
+
+func (c contentExistsErr) Error() string {
+	return c.desc
+}
+func (c contentNotFoundErr) Error() string {
+	return c.desc
+}
+func (c contentLockedErr) Error() string {
+	return c.desc
+}
+
+func (c contentExistsErr) Exists() bool {
+	return true
+}
+
+func (c contentNotFoundErr) NotFound() bool {
+	return true
+}
+
+func (c contentLockedErr) Locked() bool {
+	return true
+}
+
+// IsNotFound returns true if the error is due to a not found content item
+func IsNotFound(err error) bool {
+	if err, ok := err.(interface {
+		NotFound() bool
+	}); ok {
+		return err.NotFound()
+	}
+
+	causal, ok := err.(interface {
+		Cause() error
+	})
+	if !ok {
+		return false
+	}
+
+	return IsNotFound(causal.Cause())
+}
+
+// IsExists returns true if the error is due to an already existing content item
+func IsExists(err error) bool {
+	if err, ok := err.(interface {
+		Exists() bool
+	}); ok {
+		return err.Exists()
+	}
+
+	causal, ok := err.(interface {
+		Cause() error
+	})
+	if !ok {
+		return false
+	}
+
+	return IsExists(causal.Cause())
+}
+
+// IsLocked returns true if the error is due to a currently locked content item
+func IsLocked(err error) bool {
+	if err, ok := err.(interface {
+		Locked() bool
+	}); ok {
+		return err.Locked()
+	}
+
+	causal, ok := err.(interface {
+		Cause() error
+	})
+	if !ok {
+		return false
+	}
+
+	return IsLocked(causal.Cause())
+}

content/locks.go

@@ -1,9 +1,8 @@
 package content
 
 import (
+	"fmt"
 	"sync"
-
-	"github.com/pkg/errors"
 )
 
 // Handles locking references
@@ -20,7 +19,7 @@ func tryLock(ref string) error {
 	defer locksMu.Unlock()
 
 	if _, ok := locks[ref]; ok {
-		return errors.Wrapf(ErrLocked, "key %s is locked", ref)
+		return ErrLocked(fmt.Sprintf("key %s is locked", ref))
 	}
 
 	locks[ref] = struct{}{}

content/store.go

@@ -40,7 +40,7 @@ func (s *store) Info(ctx context.Context, dgst digest.Digest) (Info, error) {
 	fi, err := os.Stat(p)
 	if err != nil {
 		if os.IsNotExist(err) {
-			err = ErrNotFound
+			err = ErrNotFound("")
 		}
 
 		return Info{}, err
@@ -62,7 +62,7 @@ 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
 	}
@@ -85,7 +85,7 @@ func (cs *store) Delete(ctx context.Context, dgst digest.Digest) error {
 			return err
 		}
 
-		return ErrNotFound
+		return ErrNotFound("")
 	}
 
 	return nil
@@ -329,7 +329,7 @@ func (s *store) Abort(ctx context.Context, ref string) error {
 	root := s.ingestRoot(ref)
 	if err := os.RemoveAll(root); err != nil {
 		if os.IsNotExist(err) {
-			return ErrNotFound
+			return ErrNotFound("")
 		}
 
 		return err

content/writer.go

@@ -99,7 +99,7 @@ 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
 	}