Added file repository manager (20400d59) · Commits · Mirror / cc-server

cloudcontrol/server/repository.py

0 → 100644

+116 −0

Original line number	Diff line number	Diff line
		""" A repository class used to manage a file repository.
		"""

		import os
		from threading import Lock
		from hashlib import sha1

		from cloudcontrol.server.db import SObject

		from cloudcontrol.common.tql.db.tag import StaticTag


		class RepositoryOperationError(Exception):
		""" Error while repository operation.
		"""


		class Repository(object):

		""" A class abstracting operations on a file repository.
		"""

		def __init__(self, logger, server, directory, role='file'):
		self.logger = logger
		self._server = server
		self._directory = directory
		self._lock = Lock()
		self._objects = {} # Mapping between file names and tql objects
		self._role = role

		# Load TQL objects of already existing files:
		for name in self.list():
		obj_id = self._object_id(name)
		sha1_hash, content = self.load(name)
		tql_object = SObject(obj_id)
		tql_object.register(StaticTag('r', self._role))
		tql_object.register(StaticTag('hash', sha1_hash))
		tql_object.register(StaticTag('name', name))
		tql_object.register(StaticTag('size', len(content)))
		self._objects[name] = tql_object
		self._server.db.register(tql_object)

		def _fullname(self, name):
		""" Return the file fullname depending to its name.
		"""
		return os.path.join(self._directory, name)

		def _object_id(self, name):
		""" Return the TQL object id of the file.
		"""
		return '%s-%s' % (self._role, name)

		def save(self, name, content):
		""" Save a file to the repository.
		"""
		fullname = self._fullname(name)
		self.logger.debug('Saving file %r to %s', name, fullname)
		try:
		with open(fullname, 'w') as ffile:
		ffile.write(content)
		except IOError as err:
		msg = 'Error while saving: %s' % err
		raise RepositoryOperationError(msg)
		else:
		obj_id = self._object_id(name)
		sha1_hash = sha1(content).hexdigest()
		if name in self._objects:
		tql_object = self._objects[name]
		tql_object['hash'].value = sha1_hash
		tql_object['size'].value = len(content)
		else:
		tql_object = SObject(obj_id)
		tql_object.register(StaticTag('r', self._role))
		tql_object.register(StaticTag('hash', sha1_hash))
		tql_object.register(StaticTag('name', name))
		tql_object.register(StaticTag('size', len(content)))
		self._server.db.register(tql_object)
		self._objects[name] = tql_object
		return obj_id

		def load(self, name):
		""" Load a file from the repository and compute its sha1sum.

		:return: a tuple (sha1_hash, content)
		"""
		fullname = self._fullname(name)
		try:
		with open(fullname, 'r') as ffile:
		content = ffile.read()
		except IOError as err:
		msg = 'Error while saving: %s' % err
		raise RepositoryOperationError(msg)
		else:
		sha1_hash = sha1(content).hexdigest()
		self.logger.debug('Loaded plugin %r, hash = %s', name, sha1_hash)
		return sha1_hash, content

		def delete(self, name):
		""" Delete a file from the repository.

		:param name: name of the file to delete
		"""
		tql_object = self._objects.pop(name)
		if tql_object is None:
		raise RepositoryOperationError('Unknown object')
		self._server.db.unregister(tql_object)
		try:
		os.unlink(self._fullname(name))
		except OSError as err:
		msg = 'Error while deleting: %s' % err
		raise RepositoryOperationError(msg)

		def list(self):
		""" List files of the repository.
		"""
		return os.listdir(self._directory)
		No newline at end of file