Source code for omniduct.databases.druid

from __future__ import absolute_import

from interface_meta import override

from omniduct.utils.debug import logger

from .base import DatabaseClient

[docs]class DruidClient(DatabaseClient): """ This Duct connects to a Druid server using the `pydruid` python library. """ PROTOCOLS = ['druid'] DEFAULT_PORT = 80 NAMESPACE_NAMES = ['table'] NAMESPACE_QUOTECHAR = '"' NAMESPACE_SEPARATOR = '.' @override def _init(self): self.__druid = None # Connection @override def _connect(self): from pydruid.db import connect'Connecting to Druid database ...') self.__druid = connect(, self.port, path='/druid/v2/sql/', scheme='http') if self.username or self.password: logger.warning( 'Duct username and password not passed to pydruid connection. ' 'pydruid connection currently does not allow these fields to be passed.' ) @override def _is_connected(self): return self.__druid is not None @override def _disconnect(self):'Disconnecting from Druid database ...') try: self.__druid.close() except Exception: pass self.__druid = None # Querying @override def _execute(self, statement, cursor, wait, session_properties): cursor = cursor or self.__druid.cursor() cursor.execute(statement) return cursor @override def _table_list(self, namespace, like=None, **kwargs): cmd = "SELECT * FROM INFORMATION_SCHEMA.TABLES" return self.query(cmd, **kwargs) @override def _table_exists(self, table, **kwargs): logger.disabled = True try: self.table_desc(table, **kwargs) return True except: return False finally: logger.disabled = False @override def _table_drop(self, table, **kwargs): raise NotImplementedError @override def _table_desc(self, table, **kwargs): query = (""" SELECT TABLE_SCHEMA , TABLE_NAME , COLUMN_NAME , ORDINAL_POSITION , COLUMN_DEFAULT , IS_NULLABLE , DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '{}'""").format(table) return self.query(query, **kwargs) @override def _table_head(self, table, n=10, **kwargs): return self.query("SELECT * FROM {} LIMIT {}".format(table, n), **kwargs) @override def _table_props(self, table, **kwargs): raise NotImplementedError