Adds new storagedriver.FileWriter interface

Updates registry storage code to use this for better resumable writes.
Implements this interface for the following drivers:
 + Inmemory
 + Filesystem
 + S3
 + Azure

Signed-off-by: Brian Bland <brian.bland@docker.com>
This commit is contained in:
Brian Bland 2016-02-08 14:29:21 -08:00
parent 7adddecf0b
commit c69c8a3286
25 changed files with 1059 additions and 2488 deletions

View file

@ -49,15 +49,14 @@ type StorageDriver interface {
// This should primarily be used for small objects.
PutContent(ctx context.Context, path string, content []byte) error
// ReadStream retrieves an io.ReadCloser for the content stored at "path"
// Reader retrieves 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(ctx context.Context, path string, offset int64) (io.ReadCloser, error)
Reader(ctx context.Context, path string, offset int64) (io.ReadCloser, error)
// WriteStream stores the contents of the provided io.ReadCloser at a
// location designated by the given path.
// May be used to resume writing a stream by providing a nonzero offset.
WriteStream(ctx context.Context, path string, offset int64, reader io.Reader) (nn int64, err error)
// Writer returns a FileWriter which will store the content written to it
// at the location designated by "path" after the call to Commit.
Writer(ctx context.Context, path string, append bool) (FileWriter, error)
// Stat retrieves the FileInfo for the given path, including the current
// size in bytes and the creation time.
@ -83,6 +82,25 @@ type StorageDriver interface {
URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error)
}
// FileWriter provides an abstraction for an opened writable file-like object in
// the storage backend. The FileWriter must flush all content written to it on
// the call to Close, but is only required to make its content readable on a
// call to Commit.
type FileWriter interface {
io.WriteCloser
// Size returns the number of bytes written to this FileWriter.
Size() int64
// Cancel removes any written content from this FileWriter.
Cancel() error
// Commit flushes all content written to this FileWriter and makes it
// available for future calls to StorageDriver.GetContent and
// StorageDriver.Reader.
Commit() error
}
// PathRegexp is the regular expression which each file path must match. A
// file path is absolute, beginning with a slash and containing a positive
// number of path components separated by slashes, where each component is