Source Code for Module tlib.base.MysqlConnector

  1  # @author dumitru.fostic@ypg.com 
  2  # @date   May , 2014 
  3  import MySQLdb 
  4  import warnings 
  5  from tlib.base.ExceptionHelper import TLibException 
  6  from MySQLdb.cursors import DictCursor, Cursor, SSCursor, SSDictCursor 
  7   
  8   
  9 -class ConnectionError(TLibException): 
 10 -    def __init__(self, err_code, err_description): 
 11          self.code, self.description = err_code, err_description 
 12 -    def __str__(self): 
 13          return 'Connection to DB FAILURE with error(/code: description/) /%d: %s/' % (self.code, self.description) 
 14   
 15   
 16 -class AutoCommitError(TLibException): 
 17 -    def __init__(self, value): 
 18          self.value = value 
 19 -    def __str__(self): 
 20          return "Wrong argument '%s' passed in <get_autocommit_status> function. Valid args are str: 'local', 'global' or 'session'." % self.value 
 21   
 22   
 23 -class QueryError(TLibException): 
 24 -    def __init__(self, err_code, err_description): 
 25          self.code, self.description = err_code, err_description 
 26 -    def __str__(self): 
 27          return 'query function FAILURE with error(/code: description/) /%d: %s/' % (self.code, self.description) 
 28   
 29   
 30 -class ExecuteError(TLibException): 
 31 -    def __init__(self, err_code, err_description): 
 32          self.code, self.description = err_code, err_description 
 33 -    def __str__(self): 
 34          return 'execute function FAILURE with error (/code: description/) /%d: %s/' % (self.code, self.description) 
 35   
 36   
 37 -class MysqlConnector(object): 
 38      """ 
 39      Connects to MySQL DB, executes queries 
 40      Autocommit is disabled by default, commit is done with commit function 
 41      Warnings are turned into exceptions 
 42      """ 
 43 -    def __init__(self, config_data, cursor_class=None): 
 44          """ 
 45          Initialize DB connection. Turning warning into exceptions 
 46          :param cursor_class: Cursor type to use. See MySQLdb for more info 
 47          :type cursor_class: DictCursor|Cursor|SSCursor|SSDictCursor 
 48          """ 
 49          if cursor_class is None: 
 50              cursor_class = DictCursor 
 51   
 52          self.db = None 
 53          warnings.filterwarnings('error', category=MySQLdb.Warning)  # turns warnings into exceptions 
 54          try: 
 55              self.db = MySQLdb.connect(**config_data) 
 56              self.cursor = self.db.cursor(cursor_class) 
 57              self.db.autocommit(False)   # in case of autocommit will change by default to ON in future 
 58          except MySQLdb.Error, err: 
 59              raise ConnectionError(err.args[0], err.args[1]) 
 60   
 61 -    def get_autocommit_status(self, var_type='local'): 
 62          """ 
 63          returns tuple Autocommit status i.e. ({'Value': 'ON', 'Variable_name':'autocommit'},) 
 64          """ 
 65          if not var_type in ['local', 'global', 'session']: 
 66              raise AutoCommitError(var_type) 
 67   
 68          status_query = "show %s variables where variable_name = 'autocommit'" % var_type 
 69          return self.query_select(status_query) 
 70   
 71 -    def query_select(self, query): 
 72          """ 
 73          Send/execute SELECT queries, returns data from DB 
 74          :param: str MySQL query 
 75          :return: tuple with arguments dictionaries, each dictionary is a row of DB i.e. ({row_first}, {row_second}, ... ,{row_last}) 
 76          """ 
 77          try: 
 78              self.cursor.execute(query) 
 79              return self.cursor.fetchall() 
 80          except MySQLdb.Error, err: 
 81              raise QueryError(err.args[0], err.args[1]) 
 82   
 83 -    def query_execute(self, query): 
 84          """ 
 85          Sends query to DB. Can be DELETE, UPDATE 
 86          :param: str query 
 87          :return: dict {DictCursor} 
 88          """ 
 89          try: 
 90              self.cursor.execute(query) 
 91              return self.cursor 
 92          except MySQLdb.Error, err: 
 93              raise ExecuteError(err.args[0], err.args[1]) 
 94   
 95 -    def commit(self): 
 96          """ 
 97          Commits all changes, returns Exception in case of failure 
 98          """ 
 99          self.db.commit() 
100   
101 -    def rollback(self): 
102          """ 
103          Rolls back all commits, returns exception in case of failure 
104          """ 
105          self.db.rollback() 
106   
107 -    def close_cursor(self): 
108          """ 
109          Close cursor. Connection to DB is still open, new cursor can be created 
110          """ 
111          self.cursor.close() 
112          self.cursor = None 
113   
114 -    def close_db(self): 
115          """ 
116          Close DB connection. All uncommitted changes are lost 
117          """ 
118          self.db.close() 
119          self.db = None 
120   
121 -    def __del__(self): 
122          if self.cursor is not None: self.cursor.close() 
123          if self.db is not None: self.db.close() 
124