def __init__(self, connection, tables_def = None, **kwargs):
"""Initialise the historian.
The historian makes two connections to the data store. Both of
these connections are available across the main and processing
thread of the historian. topic_map and topic_meta are used as
cache for the meta data and topic maps.
:param connection: dictionary that contains necessary information to
establish a connection to the sql database. The dictionary should
contain two entries -
1. 'type' - describe the type of database (sqlite or mysql)
2. 'params' - parameters for connecting to the database.
:param tables_def: optional parameter. dictionary containing the
names to be used for historian tables. Should contain the following
keys
1. "table_prefix": - if specified tables names are prefixed with
this value followed by a underscore
2."data_table": name of the table that stores historian data,
3."topics_table": name of the table that stores the list of topics
for which historian contains data data
4. "meta_table": name of the table that stores the metadata data
for topics
:param kwargs: additional keyword arguments.
"""
self.connection = connection
self.tables_def, self.table_names = self.parse_table_def(tables_def)
self.topic_id_map = {}
self.topic_name_map = {}
self.topic_meta = {}
self.agg_topic_id_map = {}
database_type = self.connection['type']
self.db_functs_class = sqlutils.get_dbfuncts_class(database_type)
# Create two instance so connection is shared within a single thread.
# This is because sqlite only supports sharing of connection within
# a single thread.
# historian_setup and publish_to_historian happens in background thread
# everything else happens in the MainThread
# One utils class instance( hence one db connection) for main thread
self.main_thread_dbutils = self.db_functs_class(
self.connection['params'],
self.table_names)
# One utils class instance( hence one db connection) for main thread
# this gets initialized in the bg_thread within historian_setup
self.bg_thread_dbutils = None
super(SQLHistorian, self).__init__(**kwargs)
def historian_setup(self):
thread_name = threading.currentThread().getName()
_log.debug("historian_setup on Thread: {}".format(thread_name))
database_type = self.config['connection']['type']
self.tables_def, table_names = self.parse_table_def(self.config)
db_functs_class = sqlutils.get_dbfuncts_class(database_type)
self.reader = db_functs_class(self.config['connection']['params'],
table_names)
self.writer = db_functs_class(self.config['connection']['params'],
table_names)
self.reader.setup_historian_tables()
topic_id_map, topic_name_map = self.reader.get_topic_map()
self.topic_id_map.update(topic_id_map)
self.topic_name_map.update(topic_name_map)
self.agg_topic_id_map = self.reader.get_agg_topic_map()
def historian_setup(self):
thread_name = threading.currentThread().getName()
_log.debug("historian_setup on Thread: {}".format(thread_name))
database_type = self.config['connection']['type']
self.tables_def, table_names = self.parse_table_def(self.config)
db_functs_class = sqlutils.get_dbfuncts_class(database_type)
self.reader = db_functs_class(self.config['connection']['params'],
table_names)
self.writer = db_functs_class(self.config['connection']['params'],
table_names)
self.writer.setup_historian_tables()
topic_id_map, topic_name_map = self.reader.get_topic_map()
self.topic_id_map.update(topic_id_map)
self.topic_name_map.update(topic_name_map)
self.agg_topic_id_map = self.reader.get_agg_topic_map()
def configure(self, config_name, action, config):
if not config or not isinstance(config, dict):
raise ValueError("Configuration should be a valid json")
# 1. Check connection to db instantiate db functions class
connection = config.get('connection', None)
assert connection is not None
database_type = connection.get('type', None)
assert database_type is not None
params = connection.get('params', None)
assert params is not None
class_name = sqlutils.get_dbfuncts_class(database_type)
self.dbfuncts_class = class_name(connection['params'], None)
self.dbfuncts_class.setup_aggregate_historian_tables(
self.volttron_table_defs)
super(SQLAggregateHistorian, self).configure(
config_name, action, config)
def configure(self, config_name, action, config):
if not config or not isinstance(config, dict):
raise ValueError("Configuration should be a valid json")
# 1. Check connection to db instantiate db functions class
connection = config.get('connection', None)
assert connection is not None
database_type = connection.get('type', None)
assert database_type is not None
params = connection.get('params', None)
assert params is not None
class_name = sqlutils.get_dbfuncts_class(database_type)
self.dbfuncts_class = class_name(connection['params'], None)
self.dbfuncts_class.setup_aggregate_historian_tables(
self.volttron_table_defs)
super(SQLAggregateHistorian, self).configure(config_name, action,
config)
def get_dbfuncts_object(self):
db_functs_class = sqlutils.get_dbfuncts_class(self.connection['type'])
return db_functs_class(self.connection['params'], self.table_names)