depot/third_party/tvl/tools/nixery/storage/storage.go

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// Copyright 2022 The TVL Contributors
// SPDX-License-Identifier: Apache-2.0
// Package storage implements an interface that can be implemented by
// storage backends, such as Google Cloud Storage or the local
// filesystem.
package storage
import (
"context"
"io"
"net/http"
)
type Persister = func(io.Writer) (string, int64, error)
type Backend interface {
// Name returns the name of the storage backend, for use in
// log messages and such.
Name() string
// Persist provides a user-supplied function with a writer
// that stores data in the storage backend.
//
// It needs to return the SHA256 hash of the data written as
// well as the total number of bytes, as those are required
// for the image manifest.
Persist(ctx context.Context, path, contentType string, f Persister) (string, int64, error)
// Fetch retrieves data from the storage backend.
Fetch(ctx context.Context, path string) (io.ReadCloser, error)
// Move renames a path inside the storage backend. This is
// used for staging uploads while calculating their hashes.
Move(ctx context.Context, old, new string) error
// Serve provides a handler function to serve HTTP requests
// for objects in the storage backend.
Serve(digest string, r *http.Request, w http.ResponseWriter) error
}