I have made a flask application at my local computer in the debugging mode and it runs all fine. But when it comes to production, the website gives me 500 or internal server error, which I have no idea what the bug is. I am fairly new to flask production and this has been stopping me from moving forward for quite a few days.
My questions are:
1> in my local development environment, one could always print things out. But how can I see those prints in the production stage?
2> Do I see them through Apache2 log? Where is Apache2 log?
For production, I actually followed the tutorials from pythonprogramming.net. Youtube link is here:
https://www.youtube.com/watch?v=qZNL4Ku1UQg&list=PLQVvvaa0QuDc_owjTbIY4rbgXOFkUYOUB&index=2
To use a very simple example, if the code imports a package which wasn't installed, where can we see the errors?
Thanks in advance.
I've tried to use to use try ... except block for every flask function. Whenever there is an exception, it can be return to the front-end. But what about other errors?
I found out:
Use logging module
Read apache2 log from /var/log/apache2
Related
I'm on network solutions apache server. On their setup page I chose to enable error logging. Nothing ever seems to appear in the log folder though. I suppose that could be good if I really have no errors. How could I create an error that should show up in the log folder so I can test it.
If you have enabled dynamic scripts, how about a script that dies or won't compile?
#!/usr/bin/env perl
die "This script intentionally produces HTTP 500";
I finally handled that Yii1 and YiiBridge install instructions and run some sample test. The problem now is, instead use my localhost, PHPBrowser is going to an unknown server from LAN, which obviously fails all tests. Is there any configuration that can prevent this?
edit: Refs
https://codeception.com/docs/modules/Yii1.html
https://github.com/Codeception/YiiBridge
I am backing a web app with a Flask API that returns custom error codes. The API runs through Apache and the WSGI module, in daemon mode.
I included a WSGIErrorOverride Off instruction in the Apache conf file for the API (which is supposed to be the default but I included it anyway).
Yet anytime my Flask app returns a custom error code (they work when I run the app using the built-in server), Apache sends an error 500. How can I prevent that?
Thanks to comments by duskwuff and Graham Dumpleton, I found that the problem doesn't come from Apache WSGI but from my Flask app.
More precisely, I was using the Flask-RESTful package, which is in charge, among other things, of transforming my views' return values into actual responses.
When those views are decorated (here with an equivalent of #login_required), those decorators are called by the Flask-RESTful package itself, and when an exception is thrown, something goes wrong.
For some reason, my app returns the custom error when I run the built-in server and an error 500 when I run it over Apache. Not quite sure why yet, I'm guessing Flask-RESTful is doing something that is not WSGI-compliant. I was on the verge of dropping it anyway for other reasons, so I'm OK with this solution.
Update: it looks like the problem does indeed come from Flask-RESTful: https://github.com/flask-restful/flask-restful/issues/372
I've been having a problem with my (development) site hanging when I try to login using LDAP credentials. Using xdebug, I was able to pinpoint the hang to a specific line of code, which is a call to ldap_bind(...). After days of trying to understand why it is hanging, one of my debugging techniques was to disable mod_ldap, and then just try to get any error to show up in apache log (after this has started, apache error logs haven't been recording any errors while performing this http request; It 'hangs' too).
What I did
I disabled the module (sudo a2dismod mod_ldap), restarted the server (sudo service apache2 restart), and confirmed that the module isn't enabled (apache2ctl -M does not show mod_ldap)
The Problem
It still hangs when it reaches ldap_bind(), however, it shouldn't even be reaching that point because without mod_ldap, my code shouldn't even be successfully calling ldap_connect() (right?) which is returning (resource) resource id='5' type='ldap link' (meaning the call was successful). I'm expecting a NoMethod or Function error.
Why can php make a call to a module that isn't enabled, and how do I stop that behavior?
Version
Ubuntu 14.04
Apache 2.4.7
PHP 5.5.9-1ubuntu4.5
Well it turns out, I had a novice understanding of what was happening. Never occurred to me that ldap_connect() as a php call had nothing to do with mod_ldap or any apache module. Thus, disabling/enabling apache mods wasn't doing anything because... it had nothing to do with apache mods.
So... I was able to disable ldap php extension with
sudo php5dismod ldap
and able to check that it was disabled with
php -m
And sure enough, after restarting the server, running my script caused a No function error for ldap_connect() (just as I was expecting/hoping). Now I just need to figure out why ldap_bind() hangs...
I have a CakePHP app which I have been developing on a remote server. Everything is working fine on the remote server.
I'm now trying to install it on a machine with a fresh install of XAMPP. Cake is timing out. Apache is working - other things, such as phpMyAdmin, work fine. I am running Apache through port 8000, as IIS is using port 80. The OS is Windows Server 2003.
When trying to access the app, it times out, with the following error:
Fatal error: Maximum execution time of 30 seconds exceeded in C:\xampp\htdocs\cake\libs\debugger.php on line 247
I have turned URL rewriting off, that hasn't solved the problem.
I have been trying to track down the source of the problem by echoing things and then exiting the script in the cake core. I found that the script was timing out (with the same error) when the components were trying to load. I commented out my components array in app_controller, and the script ran a little further.
Now, I have tracked it down this far:
Dispatcher::dispatch();
Dispatcher::_invoke();
Controller::constructClasses();
Controller::loadModel();
ClassRegistry::init(); //called on line 635 of Controller in the "else" block of the if (PHP5) statement
In ClassRegistry::init(), the script times out on line 141, whic is as follows:
${$class} =& new $class($settings);
I have no idea where to go from here! Help much appreciated.
I got your problem.
To solve this you should do tw0 things.
1) Try to change the debug level 2 in the core.php from the config adn then change it to 0.
2) plz enable this line from the config.
line number 57 in core.php.
Configure::write('App.baseUrl', env('SCRIPT_NAME'));
regards,
archit.
Well, after following the problem a bit further, I found that the problem was coming up in Model::construct. It turns out that the hostname in my database.php file was wrong! I would have expected a "could not connect to the database..." error.