Reduce unnecessary s3 timeouts

environs/storage/interfaces.go

Index: environs/storage/interfaces.go
=== added file 'environs/storage/interfaces.go'
--- environs/storage/interfaces.go	1970-01-01 00:00:00 +0000
+++ environs/storage/interfaces.go	2013-09-18 07:29:38 +0000
@@ -0,0 +1,68 @@
+// Copyright 2013 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package storage
+
+import (
+	"io"
+	"launchpad.net/juju-core/utils"
+)
+
+// A StorageReader can retrieve and list files from a storage provider.
+type StorageReader interface {
+	// Get opens the given storage file and returns a ReadCloser
+	// that can be used to read its contents.  It is the caller's
+	// responsibility to close it after use.  If the name does not
+	// exist, it should return a *NotFoundError.
+	Get(name string) (io.ReadCloser, error)
+
+	// List lists all names in the storage with the given prefix, in
+	// alphabetical order.  The names in the storage are considered
+	// to be in a flat namespace, so the prefix may include slashes
+	// and the names returned are the full names for the matching
+	// entries.
+	List(prefix string) ([]string, error)
+
+	// URL returns a URL that can be used to access the given storage file.
+	URL(name string) (string, error)
+
+	// DefaultConsistencyStrategy returns the appropriate polling for waiting
+	// for this storage to become consistent.
+	// If the storage implementation has immediate consistency, the
+	// strategy won't need to wait at all.  But for eventually-consistent
+	// storage backends a few seconds of polling may be needed.
+	DefaultConsistencyStrategy() utils.AttemptStrategy
+
+	// ShouldRetry returns true is the specified error is such that an
+	// operation can be performed again with a chance of success. This is
+	// typically the case where the storage implementation does not have
+	// immediate consistency and needs to be given a chance to "catch up".
+	ShouldRetry(error) bool
+}
+
+// A StorageWriter adds and removes files in a storage provider.
+type StorageWriter interface {
+	// Put reads from r and writes to the given storage file.
+	// The length must give the total length of the file.
+	Put(name string, r io.Reader, length int64) error
+
+	// Remove removes the given file from the environment's
+	// storage. It should not return an error if the file does
+	// not exist.
+	Remove(name string) error
+
+	// RemoveAll deletes all files that have been stored here.
+	// If the underlying storage implementation may be shared
+	// with other actors, it must be sure not to delete their
+	// file as well.
+	// Nevertheless, use with care!  This method is only mean
+	// for cleaning up an environment that's being destroyed.
+	RemoveAll() error
+}
+
+// Storage represents storage that can be both
+// read and written.
+type Storage interface {
+	StorageReader
+	StorageWriter
+}