fixed bug when there was no dbfile, and dbmanage raise an exception

pylons_app/lib/db_manage.py

@@ -1,95 +1,98 b''
 from os.path import dirname as dn, join as jn
 from pylons_app.lib.auth import get_crypt_password
 from pylons_app.model import init_model
 from pylons_app.model.db import User, Permission
 from pylons_app.model.meta import Session, Base
 from sqlalchemy.engine import create_engine
 import logging
 import os
 import sys
 ROOT = dn(dn(dn(os.path.realpath(__file__))))
 sys.path.append(ROOT)
 
 
 
 log = logging.getLogger('db manage')
 log.setLevel(logging.DEBUG)
 console_handler = logging.StreamHandler()
 console_handler.setFormatter(logging.Formatter("%(asctime)s.%(msecs)03d" 
                                     " %(levelname)-5.5s [%(name)s] %(message)s"))
 log.addHandler(console_handler)
 
 class DbManage(object):
     def __init__(self, log_sql):
         self.dbname = 'hg_app.db'
         dburi = 'sqlite:////%s' % jn(ROOT, self.dbname)
         engine = create_engine(dburi, echo=log_sql) 
         init_model(engine)
         self.sa = Session()
+        self.db_exists = False
     
     def check_for_db(self, override):
         log.info('checking for exisiting db')
         if os.path.isfile(jn(ROOT, self.dbname)):
+            self.db_exists = True
             log.info('database exisist')
             if not override:
                 raise Exception('database already exists')
 
     def create_tables(self, override=False):
         """
         Create a auth database
         """
         self.check_for_db(override)
         if override:
             log.info("database exisist and it's going to be destroyed")
-            os.remove(jn(ROOT, self.dbname))
+            if self.db_exists:
+                os.remove(jn(ROOT, self.dbname))
         Base.metadata.create_all(checkfirst=override)
         log.info('Created tables for %s', self.dbname)
     
     def admin_prompt(self):
         import getpass
         username = raw_input('Specify admin username:')
         password = getpass.getpass('Specify admin password:')
         self.create_user(username, password, True)
         
     def create_user(self, username, password, admin=False):
         log.info('creating administrator user %s', username)
         
         new_user = User()
         new_user.username = username
         new_user.password = get_crypt_password(password)
         new_user.admin = admin
         new_user.active = True
         
         try:
             self.sa.add(new_user)
             self.sa.commit()
         except:
             self.sa.rollback()
             raise
     
     def create_permissions(self):
         #module.(access|create|change|delete)_[name]
         perms = [('admin.access_home', 'Access to admin user view'),
                  
                  ]
         
         for p in perms:
             new_perm = Permission()
             new_perm.permission_name = p[0]
             new_perm.permission_longname = p[1]
             try:
                 self.sa.add(new_perm)
                 self.sa.commit()
             except:
                 self.sa.rollback()
                 raise
         
         
         
 if __name__ == '__main__':
     dbmanage = DbManage(log_sql=True)
     dbmanage.create_tables(override=True)
     dbmanage.admin_prompt()
     dbmanage.create_permissions()