Log Writers

The purpose of a log writer is (usually) to save all log records into a persistent storage, like a log file, a database table, or to a remote syslog server.

Different log writers offer possibilities to log into different targets. Custom log writers can extend the functionality shipped with TYPO3 core.

Built-in Log Writers

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


The database writer logs into a database table. This table has to reside in the database used by TYPO3 and is not automatically created.

Option Mandatory Description Default
logTable no Database table sys_log


The ADMIN TOOLS > Log module is not adapted to the records written by the DatabaseWriter into the sys_log table. If you write such records there, you will not be able to see them using that module.

Tip: There’s a tool for viewing such records in the TYPO3 backend at gitlab.com/co-stack.com/co-stack.com/typo3-extensions/logs.

Example of a CREATE TABLE statement for logTable:

# Table structure for table 'tx_myextname_log'
# The KEY on request_id is optional
CREATE TABLE tx_myextname_log (
        request_id varchar(13) DEFAULT '' NOT NULL,
        time_micro double(16,4) NOT NULL default '0.0000',
        component varchar(255) DEFAULT '' NOT NULL,
        level tinyint(1) unsigned DEFAULT '0' NOT NULL,
        message text,
        data text,

        KEY request (request_id)


If you are using a MariaDB Galera Cluster you should definitely add a primary key field to the database definition, since it is required by Galera (this can be a normal uid field as known from other tables): MariaDB Galera Cluster - Known Limitations.


The file writer logs into a log file, one log record per line. If the log file does not exist, it will be created (including parent directories, if needed). Please make sure that your web server has write-permissions to that path and it is below the root directory of your web site (defined by \TYPO3\CMS\Core\Core\Environment::getPublicPath()). The filename is appended with a hash, that depends on the encryption key. If $GLOBALS['TYPO3_CONF_VARS']['SYS']['generateApacheHtaccess'] is set, an .htaccess file is added to the directory. It protects your log files from being accessed from the web. If the log file is not set, then TYPO3 will use a filename containing a random hash, like typo3temp/logs/typo3_7ac500bce5.log.

Option Mandatory Description Default
logFile no Path to log file typo3temp/logs/typo3_<hash>.log like for example typo3temp/logs/typo3_7ac500bce5.log
logFileInfix no Different file name to the default log configuration 'logFileInfix' => 'special' results in typo3_special_<hash>.log


Logs into the PHP error log using error_log()


Logs into the syslog (Unix only).

Option Mandatory Description Default
facility no Syslog Facility to log into. USER

Custom Log Writers

Custom log writers can be added through extensions. Every log writer has to implement the interface \TYPO3\CMS\Core\Log\Writer\WriterInterface. It is suggested to extend the abstract class \TYPO3\CMS\Core\Log\Writer\AbstractWriter 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 writer is throwing an exception while executing the writeLog() method. Only in the case that all registered writers fail, the log entry plus additional information will be added to the configured fallback logger (which defaults to the PhpErrorLog writer).