Why are the 500 Internal Server Errors not being logged into your apache error logs?
The errors that cause your 500 Internal Server Error are coming from a PHP module. By default, PHP does NOT log these errors. Reason being you want web requests go as fast as physically possible and it’s a security hazard to log errors to screen where attackers can observe them.
These instructions to enable Internal Server Error Logging are for Ubuntu 12.10
with PHP 5.3.10
and Apache/2.2.22
.
Make sure PHP logging is turned on:
-
Locate your php.ini file:
el@apollo:~$ locate php.ini /etc/php5/apache2/php.ini
-
Edit that file as root:
sudo vi /etc/php5/apache2/php.ini
-
Find this line in php.ini:
display_errors = Off
-
Change the above line to this:
display_errors = On
-
Lower down in the file you’ll see this:
;display_startup_errors ; Default Value: Off ; Development Value: On ; Production Value: Off ;error_reporting ; Default Value: E_ALL & ~E_NOTICE ; Development Value: E_ALL | E_STRICT ; Production Value: E_ALL & ~E_DEPRECATED
-
The semicolons are comments, that means the lines don’t take effect. Change those lines so they look like this:
display_startup_errors = On ; Default Value: Off ; Development Value: On ; Production Value: Off error_reporting = E_ALL ; Default Value: E_ALL & ~E_NOTICE ; Development Value: E_ALL | E_STRICT ; Production Value: E_ALL & ~E_DEPRECATED
What this communicates to PHP is that we want to log all these errors. Warning, there will be a large performance hit, so you don’t want this enabled on production because logging takes work and work takes time, time costs money.
-
Restarting PHP and Apache should apply the change.
-
Do what you did to cause the 500 Internal Server error again, and check the log:
tail -f /var/log/apache2/error.log
-
You should see the 500 error at the end, something like this:
[Wed Dec 11 01:00:40 2013] [error] [client 192.168.11.11] PHP Fatal error: Call to undefined function Foobar\\byob\\penguin\\alert() in /yourproject/ your_src/symfony/Controller/MessedUpController.php on line 249