Adding interfaces for donut driver

pkg/storage/donut/donut.go

@@ -0,0 +1,45 @@
+package donut
+
+import "io"
+
+// INTERFACES
+
+// Donut interface
+type Donut interface {
+	CreateBucket(bucket string) error
+	GetBuckets() ([]string, error)
+	GetObject(bucket, object string) (io.ReadCloser, error)
+	GetObjectMetadata(bucket, object string) (map[string]string, error)
+	GetObjectWriter(bucket, object string) (ObjectWriter, error)
+}
+
+// Bucket is an interface for managing buckets
+type Bucket interface {
+	GetObject(object string) (io.Reader, error)
+	GetObjectMetadata(object string) (map[string]string, error)
+	GetObjectWriter(object string) (ObjectWriter, error)
+	GetObjects() ([]string, error)
+}
+
+// Disk is an interface for managing disks
+type Disk interface {
+	GetBuckets(object string) ([]string, error)
+}
+
+// ObjectWriter is an interface for writing new objects
+type ObjectWriter interface {
+	Write([]byte) error
+	Close() error
+	CloseWithError(error) error
+
+	SetMetadata(map[string]string)
+	GetMetadata() map[string]string
+}
+
+// InternalObjectWriter is an interface for use internally to donut
+type InternalObjectWriter interface {
+	ObjectWriter
+
+	SetDonutMetadata(map[string]string)
+	GetDonutMetadata() map[string]string
+}

pkg/storage/donut/donutdriver.go

@@ -0,0 +1,48 @@
+package donut
+
+import (
+	"errors"
+	"io"
+)
+
+type donutDriver struct {
+	buckets map[string]Bucket
+	disks   map[string]Disk
+}
+
+// NewDonutDriver instantiates a donut driver for use in object storage
+func NewDonutDriver() Donut {
+	return donutDriver{
+		buckets: make(map[string]Bucket),
+		disks:   make(map[string]Disk),
+	}
+}
+
+func notImplemented() error {
+	return errors.New("Not Implemented")
+}
+
+// CreateBucket creates a bucket
+func (driver donutDriver) CreateBucket(bucket string) error {
+	return notImplemented()
+}
+
+// GetBuckets returns a list of buckets
+func (driver donutDriver) GetBuckets() ([]string, error) {
+	return nil, notImplemented()
+}
+
+// GetObject returns an object
+func (driver donutDriver) GetObject(bucket, object string) (io.ReadCloser, error) {
+	return nil, notImplemented()
+}
+
+// GetObjectMetadata returns object metadata
+func (driver donutDriver) GetObjectMetadata(bucket, object string) (map[string]string, error) {
+	return nil, notImplemented()
+}
+
+// GetObjectWriter returns a writer for creating a new object.
+func (driver donutDriver) GetObjectWriter(bucket, object string) (ObjectWriter, error) {
+	return nil, notImplemented()
+}