# Log Processors¶

The purpose of a log processor is (usually) to modify a log record or add more detailed information to it.

Log processors allow to manipulate log records without changing the code where the log method actually is called (inversion of control). This enables you to add any information from outside the scope of the actual calling function, for example webserver environment variables. The TYPO3 core ships some basic log processors, but more can be added with extensions.

## Built-in Log Processors¶

This section describes the log processors shipped with the TYPO3 core. Some processors have options to allow customization of the particular processor. See the Configuration section for how to use these options.

### IntrospectionProcessor¶

The introspection processor adds backtrace data about where the log event was triggered.

By default the following parameters from the original function call are added:

file
absolute path to the file.
line
line number.
class
class name.
function
function name.

If appendFullBackTrace is set, the full backtrace stack is added instead.

Option Mandatory Description Default
appendFullBackTrace no Adds a full backtrace stack to the log. FALSE
shiftBackTraceLevel no Removes the given number of entries from the top of the backtrace stack. 0

### MemoryUsageProcessor¶

The memory usage processor adds the amount of used memory to the log record (result from memory_get_usage()).

Option Mandatory Description Default
realMemoryUsage no Use real size of memory allocated from system instead of emalloc() value. TRUE
formatSize no Whether the size is formatted with GeneralUtility::formatSize() TRUE

### MemoryPeakUsageProcessor¶

The memory peak usage processor adds the peak amount of used memory to the log record (result from memory_get_peak_usage()).

Option Mandatory Description Default
realMemoryUsage no Use real size of memory allocated from system instead of emalloc() value. TRUE
formatSize no Whether the size is formatted with GeneralUtility::formatSize() TRUE

### WebProcessor¶

The web processor adds selected webserver environment variables to the log record, i.e. all possible values from \TYPO3\CMS\Core\Utility\GeneralUtility::getIndpEnv('_ARRAY').

## Custom Log Processors¶

Custom log processors can be added through extensions. Every log processor has to implement the interface \TYPO3\CMS\Core\Log\Processor\ProcessorInterface. It is suggested to extend the abstract class \TYPO3\CMS\Core\Log\Processor\AbstractProcessor which allows you use configuration options by adding the corresponding properties and setter methods.

Please keep in mind that TYPO3 will silently continue operating, in case a log processor is throwing an exception while executing the processLogRecord() method.