# Copyright BigchainDB GmbH and BigchainDB contributors # SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0) # Code is Apache-2.0 and docs are CC-BY-4.0 import logging from importlib import import_module from itertools import repeat import bigchaindb from bigchaindb.backend.exceptions import ConnectionError from bigchaindb.backend.utils import get_bigchaindb_config_value, get_bigchaindb_config_value_or_key_error from bigchaindb.common.exceptions import ConfigurationError BACKENDS = { 'localmongodb': 'bigchaindb.backend.localmongodb.connection.LocalMongoDBConnection', } logger = logging.getLogger(__name__) def connect(backend=None, host=None, port=None, name=None, max_tries=None, connection_timeout=None, replicaset=None, ssl=None, login=None, password=None, ca_cert=None, certfile=None, keyfile=None, keyfile_passphrase=None, crlfile=None): """Create a new connection to the database backend. All arguments default to the current configuration's values if not given. Args: backend (str): the name of the backend to use. host (str): the host to connect to. port (int): the port to connect to. name (str): the name of the database to use. replicaset (str): the name of the replica set (only relevant for MongoDB connections). Returns: An instance of :class:`~bigchaindb.backend.connection.Connection` based on the given (or defaulted) :attr:`backend`. Raises: :exc:`~ConnectionError`: If the connection to the database fails. :exc:`~ConfigurationError`: If the given (or defaulted) :attr:`backend` is not supported or could not be loaded. :exc:`~AuthenticationError`: If there is a OperationFailure due to Authentication failure after connecting to the database. """ backend = backend or get_bigchaindb_config_value_or_key_error('backend') host = host or get_bigchaindb_config_value_or_key_error('host') port = port or get_bigchaindb_config_value_or_key_error('port') dbname = name or get_bigchaindb_config_value_or_key_error('name') # Not sure how to handle this here. This setting is only relevant for # mongodb. # I added **kwargs for both RethinkDBConnection and MongoDBConnection # to handle these these additional args. In case of RethinkDBConnection # it just does not do anything with it. # # UPD: RethinkDBConnection is not here anymore cause we no longer support RethinkDB. # The problem described above might be reconsidered next time we introduce a backend, # if it ever happens. replicaset = replicaset or get_bigchaindb_config_value('replicaset') ssl = ssl if ssl is not None else get_bigchaindb_config_value('ssl', False) login = login or get_bigchaindb_config_value('login') password = password or get_bigchaindb_config_value('password') ca_cert = ca_cert or get_bigchaindb_config_value('ca_cert') certfile = certfile or get_bigchaindb_config_value('certfile') keyfile = keyfile or get_bigchaindb_config_value('keyfile') keyfile_passphrase = keyfile_passphrase or get_bigchaindb_config_value('keyfile_passphrase', None) crlfile = crlfile or get_bigchaindb_config_value('crlfile') try: module_name, _, class_name = BACKENDS[backend].rpartition('.') Class = getattr(import_module(module_name), class_name) except KeyError: raise ConfigurationError('Backend `{}` is not supported. ' 'BigchainDB currently supports {}'.format(backend, BACKENDS.keys())) except (ImportError, AttributeError) as exc: raise ConfigurationError('Error loading backend `{}`'.format(backend)) from exc logger.debug('Connection: {}'.format(Class)) return Class(host=host, port=port, dbname=dbname, max_tries=max_tries, connection_timeout=connection_timeout, replicaset=replicaset, ssl=ssl, login=login, password=password, ca_cert=ca_cert, certfile=certfile, keyfile=keyfile, keyfile_passphrase=keyfile_passphrase, crlfile=crlfile) class Connection: """Connection class interface. All backend implementations should provide a connection class that inherits from and implements this class. """ def __init__(self, host=None, port=None, dbname=None, connection_timeout=None, max_tries=None, **kwargs): """Create a new :class:`~.Connection` instance. Args: host (str): the host to connect to. port (int): the port to connect to. dbname (str): the name of the database to use. connection_timeout (int, optional): the milliseconds to wait until timing out the database connection attempt. Defaults to 5000ms. max_tries (int, optional): how many tries before giving up, if 0 then try forever. Defaults to 3. **kwargs: arbitrary keyword arguments provided by the configuration's ``database`` settings """ dbconf = bigchaindb.config['database'] self.host = host or dbconf['host'] self.port = port or dbconf['port'] self.dbname = dbname or dbconf['name'] self.connection_timeout = connection_timeout if connection_timeout is not None \ else dbconf['connection_timeout'] self.max_tries = max_tries if max_tries is not None else dbconf['max_tries'] self.max_tries_counter = range(self.max_tries) if self.max_tries != 0 else repeat(0) self._conn = None @property def conn(self): if self._conn is None: self.connect() return self._conn def run(self, query): """Run a query. Args: query: the query to run Raises: :exc:`~DuplicateKeyError`: If the query fails because of a duplicate key constraint. :exc:`~OperationFailure`: If the query fails for any other reason. :exc:`~ConnectionError`: If the connection to the database fails. """ raise NotImplementedError() def connect(self): """Try to connect to the database. Raises: :exc:`~ConnectionError`: If the connection to the database fails. """ attempt = 0 for i in self.max_tries_counter: attempt += 1 try: self._conn = self._connect() except ConnectionError as exc: logger.warning('Attempt %s/%s. Connection to %s:%s failed after %sms.', attempt, self.max_tries if self.max_tries != 0 else '∞', self.host, self.port, self.connection_timeout) if attempt == self.max_tries: logger.critical('Cannot connect to the Database. Giving up.') raise ConnectionError() from exc else: break