store: add blob interface with file implementation (#2004)

store/blob.go

@@ -0,0 +1,34 @@
+package store
+
+import (
+	"errors"
+	"io"
+)
+
+var (
+	// ErrMissingKey is returned when no key is passed to blob store Read / Write
+	ErrMissingKey = errors.New("Missing key")
+)
+
+// BlobStore is an interface for reading / writing blobs
+type BlobStore interface {
+	Read(key string, opts ...BlobOption) (io.Reader, error)
+	Write(key string, blob io.Reader, opts ...BlobOption) error
+	Delete(key string, opts ...BlobOption) error
+}
+
+// BlobOptions contains options to use when interacting with the store
+type BlobOptions struct {
+	// Namespace to  from
+	Namespace string
+}
+
+// BlobOption sets one or more BlobOptions
+type BlobOption func(o *BlobOptions)
+
+// BlobNamespace sets the Namespace option
+func BlobNamespace(ns string) BlobOption {
+	return func(o *BlobOptions) {
+		o.Namespace = ns
+	}
+}