silverstripe-framework/docs/en/02_Developer_Guides/07_Debugging/01_Error_Handling.md

title: Error Handling summary: Trap, fire and report user exceptions, warnings and errors.

Error Handling

SilverStripe has its own error trapping and handling support. On development sites, SilverStripe will deal harshly with any warnings or errors: a full call-stack is shown and execution stops for anything, giving you early warning of a potential issue to handle.

Triggering the error handler.

You should use user_error to throw errors where appropriate.

:::php
if(true == false) {
	user_error("I have an error problem", E_USER_ERROR);
}

if(0 / 0) {
	user_error("This time I am warning you", E_USER_WARNING);
}

Error Levels

• E_USER_WARNING: Err on the side of over-reporting warnings. Throwing warnings provides a means of ensuring that developers know:

  • Deprecated functions / usage patterns
  • Strange data formats
  • Things that will prevent an internal function from continuing. Throw a warning and return null.

• E_USER_ERROR: Throwing one of these errors is going to take down the production site. So you should only throw E_USER_ERROR if it's going to be dangerous or impossible to continue with the request.

Filesystem Logs

You can indicate a log file relative to the site root.

mysite/_config.php

:::php
if(!Director::isDev()) {
	// log errors and warnings
	SS_Log::add_writer(new SS_LogFileWriter('../silverstripe-errors-warnings.log'), SS_Log::WARN, '<=');
	
	// or just errors
	SS_Log::add_writer(new SS_LogFileWriter('../silverstripe-errors.log'), SS_Log::ERR);
	
	// or notices (e.g. for Deprecation Notifications)
	SS_Log::add_writer(new SS_LogFileWriter('../silverstripe-errors-notices.log'), SS_Log::NOTICE);
}

In addition to SilverStripe-integrated logging, it is advisable to fall back to PHPs native logging functionality. A script might terminate before it reaches the SilverStripe error handling, for example in the case of a fatal error. Make sure `log_errors` and `error_log` in your PHP ini file are configured.

Email Logs

You can send both fatal errors and warnings in your code to a specified email-address.

mysite/_config.php

:::php
if(!Director::isDev()) {
	// log errors and warnings
	SS_Log::add_writer(new SS_LogFileWriter('../silverstripe-errors-warnings.log'), SS_Log::WARN, '<=');

	// or just errors
	SS_Log::add_writer(new SS_LogEmailWriter('admin@domain.com'), SS_Log::ERR);
}

API Documentation

• [api:SS_Log]