Reputation: 357
I'm having a strange problem right now. In my program I try to catch an exception inside a class, de class is used in a separate python file but the exception bubbles trough to the calling file. How can I fix this?
Example:
main.py
#from sqlalchemy.exc import SQLAlchemyError, DatabaseError
from os import path
from helpers.db import DB
from models.group import Group
from models.entity import Entity
PROJECT_PATH = path.split(path.abspath(__file__))[0]
DATABASE_PATH = PROJECT_PATH + '/datastore/test.db'
class PasswordManager:
database = DB(DATABASE_PATH)
if __name__ == "__main__":
PasswordManager()
output
Traceback (most recent call last):
trying to build a SQLEngine
File "/home/tom/Projects/test/test/test.py", line 11, in <module>
class test:
File "/home/tom/Projects/test/test/test.py", line 23, in test
database = DB(DATABASE_PATH)
File "/home/tom/Projects/test/test/helpers/db.py", line 19, in __init__
self.buildDatabaseModels()
File "/home/tom/Projects/test/test/helpers/db.py", line 39, in buildDatabaseModels
Base.metadata.create_all(self.SQLEngine, checkfirst=True)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/schema.py", line 3308, in create_all
tables=tables)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1516, in _run_visitor
conn._run_visitor(visitorcallable, element, **kwargs)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1164, in _run_visitor
**kwargs).traverse_single(element)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 119, in traverse_single
return meth(obj, **kw)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/ddl.py", line 696, in visit_metadata
if self._can_create_table(t)]
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/ddl.py", line 674, in _can_create_table
table.name, schema=table.schema)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/dialects/sqlite/base.py", line 781, in has_table
cursor = _pragma_cursor(connection.execute(statement))
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 709, in execute
return self._execute_text(object, multiparams, params)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 858, in _execute_text
statement, parameters
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 927, in _execute_context
context)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1076, in _handle_dbapi_exception
exc_info
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/util/compat.py", line 185, in raise_from_cause
reraise(type(exception), exception, tb=exc_tb)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 920, in _execute_context
context)
File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 425, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.DatabaseError: (DatabaseError) file is encrypted or is not a database u'PRAGMA table_info("groups")' ()
DB.py
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.exc import DatabaseError, SQLAlchemyError
from models import *
from helpers import Base
from helpers.crypt import Crypt
class DB:
SQLEngine = None
SessionMaker = None
Session = None
BuildEngineErrorCount = 0
def __init__(self, db_path):
self.buildEngine(db_path)
self.buildDatabaseModels()
def buildEngine(self, db_path):
try:
self.SQLEngine = create_engine('sqlite:////' + db_path)
print "trying to build a SQLEngine"
except BaseException, er:
print "Errors %s" % er
for error in er.args:
if error == '(DatabaseError) file is encrypted or is not a database':
self.BuildEngineErrorCount += 1
c = Crypt()
c.setKey('Test')
c.decryptDB(db_path)
if self.BuildEngineErrorCount < 5:
self.buildEngine(db_path)
def buildDatabaseModels(self):
if self.SQLEngine is None:
raise Exception("No SQLEngine found")
Base.metadata.create_all(self.SQLEngine, checkfirst=True)
def createSession(self):
if self.SessionMaker is not None or self.Session is not None:
raise Exception("Session already mapped")
self.SessionMaker = sessionmaker(bind=self.SQLEngine)
self.Session = self.SessionMaker()
return self.Session
As you can see I try to catch that exception in the db class, but it isn't catching anything. Does anybody know what I do wrong?
Upvotes: 0
Views: 115
Reputation: 282198
Your exception is coming from a different method than the one you put the try-except in. Specifically, the exception comes from
Base.metadata.create_all(self.SQLEngine, checkfirst=True)
in buildDatabaseModels
, but you have your try-except in buildEngine
.
Upvotes: 2