<\/a>Setting up PHP error logging<\/h3>\nTo enable error logging for your site or application, follow these steps:<\/p>\n
\n- Locate the php.ini<\/strong>\u00a0file on your server.<\/li>\n
- Look for the line containing the\u00a0error_reporting\u00a0<\/strong>entry.<\/li>\n
- Ensure there is not a semicolon (;<\/strong>) in front of the entry.<\/li>\n
- Set the error_reporting\u00a0<\/strong>entry equal to the desired level of logging (covered next). For example, you might set it to\u00a0error_reporting = E_ALL<\/strong>.<\/li>\n<\/ul>\n
Error reporting levels<\/h3>\n
There are numerous reporting levels to allow you to select exactly what you\u2019d like to be notified of. Below are some of the most commonly used ones. A full list can be found in the official PHP documentation<\/a>.<\/p>\n\n- E_ALL<\/strong>\u2014Logs all errors and warnings<\/li>\n
- E_ERROR<\/strong>\u2014Logs fatal runtime errors<\/li>\n
- E_WARNING<\/strong>\u2014Logs non-fatal runtime errors<\/li>\n
- E_NOTICE<\/strong>\u2014Logs runtime notices (typical bugs in code)<\/li>\n<\/ul>\n
As a final step in the basic configuration of PHP error logging, you\u2019ll want to decide whether to display the errors on the client (browser). This is easily done:<\/p>\n
\n- Look for the line containing the\u00a0display_errors\u00a0<\/strong>entry in the\u00a0php.ini<\/strong> file<\/li>\n
- Ensure there is not a semicolon (;<\/strong>) in front of the entry<\/li>\n
- Set the display_errors<\/strong> entry to On<\/strong>\u00a0or Off<\/strong>.\u00a0For example,\u00a0display_errors = Off<\/strong>\u00a0will not show errors on the client<\/li>\n<\/ul>\n
Where are the error logs?<\/h3>\n
Once you\u2019re all set up with logging and generating plenty of errors (for practice!), you\u2019ve got to actually look at them to determine what\u2019s going on.<\/p>\n
The default error log differs from environment to environment, so it\u2019s advisable to manually set the location of the file. Here\u2019s how:<\/p>\n
\n- Look for the line containing the\u00a0error_log<\/strong>\u00a0entry in the php.ini<\/strong>\u00a0file<\/li>\n
- Ensure there is not a semicolon (;<\/strong>) in front of the entry<\/li>\n
- Set the error_log<\/strong>\u00a0entry to the desired path of the log file. For example, you might use\u00a0error_log = \/logs\/php-errors.log<\/strong>.<\/li>\n<\/ul>\n
Note this, though: you must restart your server for the changes to the\u00a0php.ini<\/strong> file to take effect.<\/p>\n![\"random](\"https:\/\/stackify.com\/wp-content\/uploads\/2019\/01\/word-image-4.jpeg\")
<\/p>\n
How to use PHP error logs effectively<\/h3>\n
There are several handy error logging functions built directly into the PHP engine, which should be enough to cover basic use cases. When your codebase gets to a point where it needs more advanced solutions, something like Stackify\u2019s post on PHP logging best practices may be what you\u2019re looking for<\/p>\n
Some\u00a0more commonly used error logging functions are covered below, but you can find a comprehensive list (naturally)\u00a0in the official PHP documentation<\/a>.<\/p>\nerror_log()<\/h3>\n
The\u00a0error_log()\u00a0<\/strong>\u00a0function allows for a string (required) to be sent to the log file. You can also send the message to an email address. There are\u00a0a\u00a0few other options, but they\u2019re more advanced so they won\u2019t be covered here.<\/p>\nIn its most basic form, error_log()<\/strong>\u00a0writes a message to the error log:<\/p>\nerror_log(\u201cThere\u2019s been a problem!\u201d);<\/code><\/pre>\nUsing this function to troubleshoot data structures or variables is fairly straightforward. Here\u2019s an example:<\/p>\n
$toolsArray = array(\"Retrace\", \"Basic Error Logging\", \"Hammer\");\nerror_log(print_r($toolsArray, true));<\/code><\/pre>\nIn this way, the contents of the variable sent as the first parameter of the print_r()<\/strong>\u00a0function will be displayed in the logs, which is a great way to keep track of data that may change over time or needs to be monitored during development.<\/p>\ndebug_print_backtrace()<\/h3>\n
While viewing code backtraces isn\u2019t typically done via the error log files, it can be helpful for smaller applications or when getting familiar with troubleshooting.<\/p>\n
The most readable way to send a backtrace to the log file is:<\/p>\n
ob_start();\ndebug_print_backtrace();\nerror_log(ob_get_clean());<\/code><\/pre>\nThis uses PHP\u2019s built-in buffer as well as the previously mentioned error_log() <\/strong>function to provide insight as to the source of errors produced by an application.<\/p>\nClean up after yourself<\/h3>\n
PHP error logs don\u2019t typically clear or truncate themselves by default. Good practice suggests you only enable logging when needed during development and you delete log files when they\u2019re no longer needed.<\/p>\n
Where to go from here<\/h3>\n
Now you\u2019ve got all the tools for effective error logging in PHP, you can debug with confidence and eventually explore more advanced utilities like Retrace<\/a>. Retrace allows you to see the error in context with the rest of your logging messages. These additional insights will give you a trail into what was happening leading up to the error.<\/p>\n![\"code](\"https:\/\/stackify.com\/wp-content\/uploads\/2019\/01\/word-image-5.jpeg\")
<\/p>\n
Error reporting levels<\/h3>\n
There are numerous reporting levels to allow you to select exactly what you\u2019d like to be notified of. Below are some of the most commonly used ones. A full list can be found in the official PHP documentation<\/a>.<\/p>\n As a final step in the basic configuration of PHP error logging, you\u2019ll want to decide whether to display the errors on the client (browser). This is easily done:<\/p>\n Once you\u2019re all set up with logging and generating plenty of errors (for practice!), you\u2019ve got to actually look at them to determine what\u2019s going on.<\/p>\n The default error log differs from environment to environment, so it\u2019s advisable to manually set the location of the file. Here\u2019s how:<\/p>\n Note this, though: you must restart your server for the changes to the\u00a0php.ini<\/strong> file to take effect.<\/p>\n There are several handy error logging functions built directly into the PHP engine, which should be enough to cover basic use cases. When your codebase gets to a point where it needs more advanced solutions, something like Stackify\u2019s post on PHP logging best practices may be what you\u2019re looking for<\/p>\n Some\u00a0more commonly used error logging functions are covered below, but you can find a comprehensive list (naturally)\u00a0in the official PHP documentation<\/a>.<\/p>\n The\u00a0error_log()\u00a0<\/strong>\u00a0function allows for a string (required) to be sent to the log file. You can also send the message to an email address. There are\u00a0a\u00a0few other options, but they\u2019re more advanced so they won\u2019t be covered here.<\/p>\n In its most basic form, error_log()<\/strong>\u00a0writes a message to the error log:<\/p>\n Using this function to troubleshoot data structures or variables is fairly straightforward. Here\u2019s an example:<\/p>\n In this way, the contents of the variable sent as the first parameter of the print_r()<\/strong>\u00a0function will be displayed in the logs, which is a great way to keep track of data that may change over time or needs to be monitored during development.<\/p>\n While viewing code backtraces isn\u2019t typically done via the error log files, it can be helpful for smaller applications or when getting familiar with troubleshooting.<\/p>\n The most readable way to send a backtrace to the log file is:<\/p>\n This uses PHP\u2019s built-in buffer as well as the previously mentioned error_log() <\/strong>function to provide insight as to the source of errors produced by an application.<\/p>\n PHP error logs don\u2019t typically clear or truncate themselves by default. Good practice suggests you only enable logging when needed during development and you delete log files when they\u2019re no longer needed.<\/p>\n Now you\u2019ve got all the tools for effective error logging in PHP, you can debug with confidence and eventually explore more advanced utilities like Retrace<\/a>. Retrace allows you to see the error in context with the rest of your logging messages. These additional insights will give you a trail into what was happening leading up to the error.<\/p>\n\n
\n
Where are the error logs?<\/h3>\n
\n
<\/p>\nHow to use PHP error logs effectively<\/h3>\n
error_log()<\/h3>\n
error_log(\u201cThere\u2019s been a problem!\u201d);<\/code><\/pre>\n$toolsArray = array(\"Retrace\", \"Basic Error Logging\", \"Hammer\");\nerror_log(print_r($toolsArray, true));<\/code><\/pre>\ndebug_print_backtrace()<\/h3>\n
ob_start();\ndebug_print_backtrace();\nerror_log(ob_get_clean());<\/code><\/pre>\nClean up after yourself<\/h3>\n
Where to go from here<\/h3>\n
<\/p>\n