+# Cumulus: Efficient Filesystem Backup to the Cloud
+# Copyright (C) 2008-2010 The Cumulus Developers
+# See the AUTHORS file for a list of contributors.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+from __future__ import division, print_function, unicode_literals
+
+import importlib
import re
+try:
+ # Python 3
+ from urllib import parse as urlparse
+ from urllib.parse import quote, unquote
+except ImportError:
+ # Python 2
+ from urllib import quote, unquote
+ import urlparse
type_patterns = {
'checksums': re.compile(r"^snapshot-(.*)\.(\w+)sums$"),
'segments': re.compile(r"^([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})(\.\S+)?$"),
- 'snapshots': re.compile(r"^snapshot-(.*)\.lbs$")
+ 'snapshots': re.compile(r"^snapshot-(.*)\.(cumulus|lbs)$")
}
-class Store:
+class NotFoundError(KeyError):
+ """Exception thrown when a file is not found in a repository."""
+
+ pass
+
+class Store(object):
"""Base class for all cumulus storage backends."""
- def list(self, type):
- raise NotImplementedException
+ def __init__(self, url):
+ """Initializes a new storage backend.
+
+ Params:
+ url: The parsed (by urlsplit) URL that specifies the storage
+ location.
+ """
+ pass
+
+ # TODO: Implement context manager.
+
+ def list(self, path):
+ raise NotImplementedError
+
+ def get(self, path):
+ raise NotImplementedError
+
+ def put(self, path, fp):
+ raise NotImplementedError
+
+ def delete(self, path):
+ raise NotImplementedError
+
+ def stat(self, path):
+ raise NotImplementedError
+
+ def scan(self, path):
+ """Cache file information stored in this backend.
+
+ This might make subsequent list or stat calls more efficient, but this
+ function is intended purely as a performance optimization."""
+
+ pass
+
+ def close(self):
+ """Tear down the connection explicitly if needed
+
+ Currently needed for sftp to be able to end the program."""
+
+ pass
+
+ def __del__(self):
+ self.close()
+
+def open(url):
+ """Parse a storage url, then locate and initialize a backend for it."""
+ parsed_url = urlparse.urlsplit(url)
- def get(self, type, name):
- raise NotImplementedException
+ # If there is no scheme, fall back to treating the string as local path and
+ # construct a file:/// URL.
+ if not parsed_url.scheme:
+ parsed_url = urlparse.SplitResult("file", "", quote(url), "", "")
- def put(self, type, name, fp):
- raise NotImplementedException
+ try:
+ # TODO: Support a registry for schemes that don't map to a module.
+ if re.match(r"^\w+$", parsed_url.scheme):
+ handler = importlib.import_module("cumulus.store.%s" %
+ parsed_url.scheme)
+ obj = handler.Store(parsed_url)
+ return obj
+ except ImportError:
+ # Fall through to error below
+ pass
- def delete(self, type, name):
- raise NotImplementedException
+ raise NotImplementedError("Scheme %s not implemented" % scheme)