ca0084fad1
Custom storage drivers can register a factory to create the driver by name, similar to the database/sql package's Register and Open factory.Create returns an in-process driver if registered or an IPC driver if one can be found, erroring otherwise This standardizes parameter passing for creation of storage drivers Also adds documentation for storagedriver package and children
59 lines
2.1 KiB
Go
59 lines
2.1 KiB
Go
package storagedriver
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// Defines methods that a Storage Driver must implement for a filesystem-like key/value object storage
|
|
type StorageDriver interface {
|
|
// Retrieve the content stored at "path" as a []byte
|
|
// Should primarily be used for small objects
|
|
GetContent(path string) ([]byte, error)
|
|
|
|
// Store the []byte content at a location designated by "path"
|
|
// Should primarily be used for small objects
|
|
PutContent(path string, content []byte) error
|
|
|
|
// Retrieve an io.ReadCloser for the content stored at "path" with a given byte offset
|
|
// May be used to resume reading a stream by providing a nonzero offset
|
|
ReadStream(path string, offset uint64) (io.ReadCloser, error)
|
|
|
|
// Store the contents of the provided io.ReadCloser at a location designated by "path"
|
|
// The driver will know it has received the full contents when it has read "size" bytes
|
|
// May be used to resume writing a stream by providing a nonzero offset
|
|
// The offset must be no larger than the number of bytes already written to this path
|
|
WriteStream(path string, offset, size uint64, readCloser io.ReadCloser) error
|
|
|
|
// Retrieve the byte offset at which it is safe to continue writing at "path"
|
|
ResumeWritePosition(path string) (uint64, error)
|
|
|
|
// Recursively lists the objects stored at a subpath of the given prefix
|
|
List(prefix string) ([]string, error)
|
|
|
|
// Moves an object stored at sourcePath to destPath, removing the original object
|
|
// Note: This may be no more efficient than a copy followed by a delete for many implementations
|
|
Move(sourcePath string, destPath string) error
|
|
|
|
// Recursively deletes all objects stored at "path" and its subpaths
|
|
Delete(path string) error
|
|
}
|
|
|
|
// Error returned when operating on a nonexistent path
|
|
type PathNotFoundError struct {
|
|
Path string
|
|
}
|
|
|
|
func (err PathNotFoundError) Error() string {
|
|
return fmt.Sprintf("Path not found: %s", err.Path)
|
|
}
|
|
|
|
// Error returned when attempting to read or write from an invalid offset
|
|
type InvalidOffsetError struct {
|
|
Path string
|
|
Offset uint64
|
|
}
|
|
|
|
func (err InvalidOffsetError) Error() string {
|
|
return fmt.Sprintf("Invalid offset: %d for path: %s", err.Offset, err.Path)
|
|
}
|