RE: [sqlalchemy] Re: information about filed create_engine
Eduardo wrote:
/.../.../python2.6/site-packages/SQLAlchemy-0.6.5-
py2.6.egg/sqlalchemy/
dialects/postgresql/psycopg2.py, line 234, in dbapi
psycopg = __import__('psycopg2')
ImportError: No module named psycopg2
The module psycopg2 is already installed in the site-packages
directory. I even included the path in the system variable by :
sys.path.append('/.../.../python2.6/site-packages/') in the wsgi
script.Still it won't work.
Why?
OK, this is definitely no longer an SQLAlchemy issue and more of a
mod_wsgi issue - you might get more help over on their mailing list
(http://code.google.com/p/modwsgi/wiki/WhereToGetHelp).
I believe psycopg2 is not a pure python module - it has a binary
component. Was it compiled with the same version of python that mod_wsgi
was?
Try this wsgi script (based on one from
http://code.google.com/p/modwsgi/wiki/InstallationIssues)
import sys
from pprint import pformat
def application(environ, start_response):
status = '200 OK'
output = (sys.prefix: %r\nsys.path: %s\n
% (sys.prefix, pformat(sys.path))
response_headers = [('Content-type', 'text/plain'),
('Content-Length', str(len(output)))]
start_response(status, response_headers)
return [output]
It would be worth comparing the output from that with the values of
sys.prefix and sys.path when run from bottle.
Hope that helps,
Simon
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RE: [sqlalchemy] Re: information about filed create_engine
-Original Message-
From: sqlalchemy@googlegroups.com [mailto:sqlalchemy@googlegroups.com]
On Behalf Of Eduardo
Sent: 18 July 2011 14:12
To: sqlalchemy
Subject: [sqlalchemy] Re: information about filed create_engine
I dont get any log. The access strings from the local and wsgi
applications are identical so the script should connect to the same
database. I encountered problems with create_engine. What type of
exception can this method throw?
The application catches: TypeError, ValueError and OperationalError.
Is there any other Error or some universal sqlalchemy error that can
indicate me where the problem is?
Thanks
I'm sorry - I still don't understand your setup. How do you know that
you've encountered problems with create_engine if you're not getting
any kind of exception from it?
If you really think that create_engine is failing but the exception is
being caught silently, why not change your code so that you've got an
exception handler around create_engine:
try:
engine = create_engine(your_connection_string)
except Exception, e:
import traceback
log_file = open('/tmp/sqlalchemy_errors', 'w+')
log_file.write('Exception from create_engine\n')
log_file.write('%s\n' % e)
log_file.write(traceback.format_exc())
raise
But your life would be much easier if you learnt how to configure
SQLAlchemy's built-in logging features:
http://www.sqlalchemy.org/docs/core/engines.html#configuring-logging
What WSGI server and web framework are you using (if any)? It sounds
like they are hampering your efforts to debug this. You might find it
easier to run a very simple wsgi server such as the one in the wsgiref
module:
http://docs.python.org/library/wsgiref.html#module-wsgiref.simple_server
Simon
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RE: [sqlalchemy] Re: information about filed create_engine
-Original Message- From: sqlalchemy@googlegroups.com [mailto:sqlalchemy@googlegroups.com] On Behalf Of Eduardo Sent: 18 July 2011 15:54 To: sqlalchemy Subject: [sqlalchemy] Re: information about filed create_engine Yes, I use wsgi server of the python library bottle and I don't have any problem but when I want to use the same script via the apache web server I get only a server error no exception could be caught not even by using the code snippet from you (Thanks by the way). I simply included many print lines that appear in the error log file. The create_engine fails (I know it from try and except) but I cannot catch any exception that sheds some light on the reason of the failure. If you are getting a generic server error from Apache, you'll normally find the reason in the Apache error log (the location depends on your installation, but typically it is something like /var/log/httpd/error_log. Does that shed any light on the problem? Simon -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
RE: [sqlalchemy] Re: information about filed create_engine
Eduardo wrote On Jul 13, 7:11 pm, King Simon-NFHD78 simon.k...@motorolasolutions.com wrote: Eduardo wrote Hi, I am trying to prompt an answer from a database after failed create_engine command. I searched through the source code and I found TypeError, and ValueError returns but they relate (if I understood well only to the access parameters). My problem is that I am sure that my access parameters are correct but for some reason the creation of the engine fails. Is there any way to get information why the engin could not be created. The access to db log files is not granted! Thanks What kind of database are you trying to connect to? Are you getting a Python exception, and if so, can you show us the traceback? Simon !) PostgresSQL 2) I don't get any Python exception. So how do you know it's failing then? Simon -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
RE: [sqlalchemy] Re: information about filed create_engine
Eduardo wrote When I use the same script with a standalone application it works but when I try to run it as a wsgi application it fails (wsgi logs does not contain any information regarding the failure!) Try turning on SQL logging (either by passing echo='debug') to create_engine, or by configuring the python logging package as described on http://www.sqlalchemy.org/docs/core/engines.html#configuring-logging. Then you should see the SQL being issued and the results coming back from the database. How are you configuring transactions? Is it possible that the transaction isn't being committed at the end of the web request, so any changes you've made are being discarded? Simon -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
RE: [sqlalchemy] Re: information about filed create_engine
Eduardo wrote When I use the same script with a standalone application it works but when I try to run it as a wsgi application it fails (wsgi logs does not contain any information regarding the failure!) Try turning on SQL logging (either by passing echo='debug') to create_engine, or by configuring the python logging package as described on http://www.sqlalchemy.org/docs/core/engines.html#configuring-logging. Then you should see the SQL being issued and the results coming back from the database. How are you configuring transactions? Is it possible that the transaction isn't being committed at the end of the web request, so any changes you've made are being discarded? Simon -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
RE: [sqlalchemy] Re: information about filed create_engine
Eduardo wrote: On Jul 14, 10:49 am, King Simon-NFHD78 simon.k...@motorolasolutions.com wrote: Eduardo wrote When I use the same script with a standalone application it works but when I try to run it as a wsgi application it fails (wsgi logs does not contain any information regarding the failure!) Try turning on SQL logging (either by passing echo='debug') to create_engine, or by configuring the python logging package as described onhttp://www.sqlalchemy.org/docs/core/engines.html#configuring- logging. Then you should see the SQL being issued and the results coming back from the database. How are you configuring transactions? Is it possible that the transaction isn't being committed at the end of the web request, so any changes you've made are being discarded? Simon My application only queries the database there are no inputs and therefore no transactions involved. What was the result of turning on SQL logging? Are you sure you're even pointing at the same database that you were when you ran the standalone script? Try printing the value of session.bind.url (or including it in HTTP response, if you don't have easy access to the stdout from your wsgi script) Simon -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
