I am getting an Interface Error/ Operational Error while running my Django application with FastCGI.On checking the access log ( of lighttpd) i find these errors pop up which are usually related to closing some db connection or the other.
The browser displays one of the two things - Unhandled Exception or Connection Terminated unsuccessfully message. Upon refreshing the page once ( usually) the errors seem to go off.
How can I prevent this from happening ? The system really behaves in an erratic fashion.
There could be 2 reasons for this problem occuring.
1. Not all URLs mentioned in your urls.py are reversing properly.
2. This is the tough part - Somewhere in the project an import is failing. It may be importing a method which does not exist.
I faced the same problem and I discovered that there were many imports like the ones mentioned in the second point.
I faced the same problem, and wrote my own solution after finding nothing from the web. Please check my blogpost here: Simple Python Utility to check all Imports in your project
Ofcourse this will only help you to get to the solution of the original issue pretty quickly and not the actual solution for your problem by itself.
Related
I have deployed a solution from my development area to two other separate servers/organisations. In this solution I am using some scripts on an entity form as soon as they load. In my development area and one of the others everything seems to work fine but in the other one i get an error as soon as i open the form saying "Error loading resource: syntax error". The error message relates to a function i am calling from another script from my on load script.
So i'm not sure if it is a coding error on my part as it does work in two of the CRM systems. But is there any settings or configuration that could affect it? Or an easy way to check what the issue is?
Thanks
I think i may have found an answer to this, it appears that the code is not picking up the CRM system's server and organisation name correctly for some reason on this instance. So i'm going to check through the code to see why this is
I am using mongoengine and would like to run connect() after settings (not inside them as suggested in its docs). This is actually more like a general question how to run code right after all settings are loaded.
Update: I need a solution for management commands as well. Common approach is adding a middleware with exception MiddlewareNotUsed or adding code to root urls.py, but both don't work for commands.
The normal place for startup-like code is in a urls.py (when you need the settings to be already loaded). Django doesn't have a good spot yet for this.
(There is an "app refactor" branch that a gsoc student worked on in 2011, but it didn't get merged into core django yet. This "app refactor" includes a solution to your very problem, but that doesn't help you...)
You mention that a management command also needs it. Is that your own management command? Nothing stops you from importing the urls.py there, is it?
This is sadly one of the few Django weak points. Luckily there aren't that many :-)
I have a CF9 site set up locally on OSX Snow Leopard, and it's started to behave very strangely - probably about 1 out of every 5 times I load any page in the site, it will throw a 'Cannot find CFML template for custom tag' error. I just refresh the page and then everything works fine. It can happen on any page, but it never happens consistently with any one page. Furthermore, this doesn't happen at all on the live server when the code is checked in through SVN, so I figure it has to be some kind of configuration problem on my local instance. I can still do my work, but it's pretty annoying having to refresh pages ALL the time. Has anyone run into similar difficulties?
Try using <cfmodule template="pathTo/yourTag.cfm"> rather than <cf_yourtag>, so you can specify the exact location of the template (in case the server is getting confused as to where it resides).
FYI, this is based on a tip from Raymond Camden's blog post: http://www.raymondcamden.com/index.cfm/2006/8/17/ColdFusion-Custom-Tag-Tips
Chris, odd that I should run into your question now, as this just started happening to me last night. I have all of my CF errors being emailed to me, and I am seeing that similar problems are happening across multiple sites that all run the same software, some of which haven't been touched in a long time. That got me thinking, it's probably a corrupt compiled template in the CF cache. You can recompile the template by making a slight change to it, say add an extra line or a comment or something, then access the site again. Or, purge the whole cache and let CF rebuild everything, which is likely what I'll do since who knows what else might be affected.
Clearing the Cache in Coldfusion Production server
I sometimes get
Could not find the ColdFusion Component or Interface Answer.
and simply doing a refresh fixes the problem.
This is not case where the program is being refreshed from ftp while I try to browse from it: no development is being done. But every once in a while I'll get it while trying to do a createobject.
Q: Is there a best practice for sleeping and trying again if instantiating a component fails?
Are you using a cluster of servers? If so perhaps you have one server misconfigured - perhaps a missing mapping - and when you get served from that server you see the issue? That might explain the way it seems to only sometimes happen.
By the way, instansiation of CFCs should always work - you should not be trying to code around this issue by sleeping and trying again.
Phillip, any chance this is on cf 9.0.1, and you're using the "import" keyword?
The reason I ask is that I've seen behavior -- and logged a bug report on it -- where if I have two different object creations on the same page (or in another CFC... doesn't matter), both from the same package, and I'm not using the fully qualified CFC name but instead am using import, then the first createObject() will succeed and the second will fail with the "could not find ... " error.
I wonder if something like that could be at work here.
We've got some really strange extraneous DB hits happening in our project. Is there any way to monitor where the requests are coming from, possibly by line number? The SQL printing middleware helps, but we've looked everywhere those kinds of requests might be generated and can't find the source.
If the above isn't possible, any pointers on narrowing down the source would be greatly appreciated.
To find the code executing queries, you can install django-debug-toolbar to figure out what commands are being executed and which tables they're operating on.
Once you've done that, try hooking into the appropriate Django signals for those models and using print and assert to narrow the code.
I'm sure there's a better way to do some of this (a python debugger?) but this is the first thing that comes to mind and probably what I would end up doing myself.
if you want track SQL queries for performance optimization and debug purpose and how to monitor query call in Django
for that this blog will help you out
Tracking SQL Queries for a Request using Django