-
-
-class IotlabDB(object):
- """ SQL Alchemy connection class.
- From alchemy.py
- """
- # Stores the unique Singleton instance-
- _connection_singleton = None
- # defines the database name
- dbname = "iotlab_sfa"
-
- class Singleton:
- """
- Class used with this Python singleton design pattern to allow the
- definition of one single instance of iotlab db session in the whole
- code. Wherever a conenction to the database is needed, this class
- returns the same instance every time. Removes the need for global
- variable throughout the code.
- """
-
- def __init__(self, config, debug=False):
- self.iotlab_engine = None
- self.iotlab_session = None
- self.url = None
- self.create_iotlab_engine(config, debug)
- self.session()
-
- def create_iotlab_engine(self, config, debug=False):
- """Creates the SQLAlchemy engine, which is the starting point
- for any SQLAlchemy application.
- :param config: configuration object created by SFA based on the
- configuration file in /etc
- :param debug: if set to true, echo and echo pool will be set to true
- as well. If echo is True, all statements as well as a repr()
- of their parameter lists to the engines logger, which defaults
- to sys.stdout. If echo_pool is True, the connection pool will
- log all checkouts/checkins to the logging stream. A python
- logger can be used to configure this logging directly but
- so far it has not been configured. Refer to sql alchemy engine
- documentation.
- :type config: Config instance (sfa.util.config)
- :type debug: bool
- """
-
- if debug is True:
- l_echo_pool = True
- l_echo = True
- else:
- l_echo_pool = False
- l_echo = False
- # the former PostgreSQL.py used the psycopg2 directly and was doing
- #self.connection.set_client_encoding("UNICODE")
- # it's unclear how to achieve this in sqlalchemy, nor if it's needed
- # at all
- # http://www.sqlalchemy.org/docs/dialects/postgresql.html#unicode
- # we indeed have /var/lib/pgsql/data/postgresql.conf where
- # this setting is unset, it might be an angle to tweak that if need
- # be try a unix socket first
- # - omitting the hostname does the trick
- unix_url = "postgresql+psycopg2://%s:%s@:%s/%s" \
- % (config.SFA_DB_USER, config.SFA_DB_PASSWORD,
- config.SFA_DB_PORT, IotlabDB.dbname)
-
- # the TCP fallback method
- tcp_url = "postgresql+psycopg2://%s:%s@%s:%s/%s" \
- % (config.SFA_DB_USER, config.SFA_DB_PASSWORD,
- config.SFA_DB_HOST, config.SFA_DB_PORT, IotlabDB.dbname)
-
- for url in [unix_url, tcp_url]:
- try:
- self.iotlab_engine = create_engine(
- url, echo_pool=l_echo_pool, echo=l_echo)
- self.check()
- self.url = url
- return
- except:
- pass
- self.iotlab_engine = None
-
- raise Exception("Could not connect to database")
-
- def check(self):
- """ Check if a table exists by trying a selection
- on the table.
-
- """
- self.iotlab_engine.execute("select 1").scalar()
-
-
- def session(self):
- """
- Creates a SQLalchemy session. Once the session object is created
- it should be used throughout the code for all the operations on
- tables for this given database.
-
- """
- if self.iotlab_session is None:
- Session = sessionmaker()
- self.iotlab_session = Session(bind=self.iotlab_engine)
- return self.iotlab_session
-
- def close_session(self):
- """
- Closes connection to database.
-
- """
- if self.iotlab_session is None:
- return
- self.iotlab_session.close()
- self.iotlab_session = None
-
-
- def update_jobs_in_iotlabdb(self, job_oar_list, jobs_psql):
- """ Cleans the iotlab db by deleting expired and cancelled jobs.
-
- Compares the list of job ids given by OAR with the job ids that
- are already in the database, deletes the jobs that are no longer in
- the OAR job id list.
-
- :param job_oar_list: list of job ids coming from OAR
- :type job_oar_list: list
- :param job_psql: list of job ids from the database.
- type job_psql: list
-
- """
- #Turn the list into a set
- set_jobs_psql = set(jobs_psql)
-
- kept_jobs = set(job_oar_list).intersection(set_jobs_psql)
- logger.debug("\r\n \t update_jobs_in_iotlabdb jobs_psql %s \r\n \
- job_oar_list %s kept_jobs %s "
- % (set_jobs_psql, job_oar_list, kept_jobs))
- deleted_jobs = set_jobs_psql.difference(kept_jobs)
- deleted_jobs = list(deleted_jobs)
- if len(deleted_jobs) > 0:
- self.iotlab_session.query(IotlabXP).filter(IotlabXP.job_id.in_(deleted_jobs)).delete(synchronize_session='fetch')
- self.iotlab_session.commit()
- return
-
- def __init__(self, config, debug=False):
- self.sl_base = IotlabBase
-
- # Check whether we already have an instance
- if IotlabDB._connection_singleton is None:
- IotlabDB._connection_singleton = IotlabDB.Singleton(config, debug)
-
- # Store instance reference as the only member in the handle
- self._EventHandler_singleton = IotlabDB._connection_singleton
-
- def __getattr__(self, aAttr):
- """
- Delegate access to implementation.
-
- :param aAttr: Attribute wanted.
- :returns: Attribute
- """
- return getattr(self._connection_singleton, aAttr)
-
-
-
- # def __setattr__(self, aAttr, aValue):
- # """Delegate access to implementation.
-
- # :param attr: Attribute wanted.
- # :param value: Vaule to be set.
- # :return: Result of operation.
- # """
- # return setattr(self._connection_singleton, aAttr, aValue)
-
- def exists(self, tablename):
- """
- Checks if the table specified as tablename exists.
- :param tablename: name of the table in the db that has to be checked.
- :type tablename: string
- :returns: True if the table exists, False otherwise.
- :rtype: bool
-
- """
- metadata = MetaData(bind=self.iotlab_engine)
- try:
- table = Table(tablename, metadata, autoload=True)
- return True
-
- except NoSuchTableError:
- logger.log_exc("SLABPOSTGRES tablename %s does not exist"
- % (tablename))
- return False
-
- def createtable(self):
- """
- Creates all the table sof the engine.
- Uses the global dictionnary holding the tablenames and the table schema.
-
- """
-
- logger.debug("SLABPOSTGRES createtable \
- IotlabBase.metadata.sorted_tables %s \r\n engine %s"
- % (IotlabBase.metadata.sorted_tables, self.iotlab_engine))
- IotlabBase.metadata.create_all(self.iotlab_engine)
- return