While CakePHP core Configure Class settings can really help you see what’s happening under the hood, there are certain times that you’ll need to log data to the disk in order to find out what’s going on. In a world that is becoming more dependent on technologies like SOAP and AJAX, debugging can be rather difficult.

Logging can also be a way to find out what’s been going on in your application over time. What search terms are being used? What sorts of errors are my users being shown? How often is a particular query being executed?

Logging data in CakePHP is easy - the log() function is a part of the Object class, which is the common ancestor for almost all CakePHP classes. If the context is a CakePHP class (Model, Controller, Component... almost anything), you can log your data. You can also use CakeLog::write() directly.

Writing to logs

Writing to the log files can be done in 2 different ways. The first is to use the static CakeLog::write() method.

CakeLog::write('debug', 'Something did not work');

The second is to use the log() shortcut function available on any class that extends Object. Calling log() will internally call CakeLog::write().

//Executing this inside a CakePHP class:
$this->log("Something did not work!", 'debug');

All configured log streams are written to sequentially each time CakeLog::write() is called. You do not need to configure a stream in order to use logging. If no streams are configured when the log is written to, a default stream using the core FileLog class will be configured to output into app/tmp/logs/ just as CakeLog did in CakePHP 1.2

Using the default FileLog class

While CakeLog can be configured to write to a number of user configured logging adapters, it also comes with a default logging configuration. This configuration is identical to how CakeLog behaved in CakePHP 1.2. The default logging configuration will be used any time there are no other logging adapters configured. Once a logging adapter has been configured you will need to also configure FileLog if you want file logging to continue.

As its name implies FileLog writes log messages to files. The type of log message being written determines the name of the file the message is stored in. If a type is not supplied, LOG_ERROR is used which writes to the error log. The default log location is app/tmp/logs/$type.log

//Executing this inside a CakePHP class:
 $this->log("Something didn't work!");

//Results in this being appended to app/tmp/logs/error.log
2007-11-02 10:22:02 Error: Something didn't work!

You can specify a custom log names, using the second parameter. The default built-in FileLog class will treat this log name as the file you wish to write logs to.

//called statically
CakeLog::write('activity', 'A special message for activity logging');

//Results in this being appended to app/tmp/logs/activity.log (rather than error.log)
2007-11-02 10:22:02 Activity: A special message for activity logging

The configured directory must be writable by the web server user in order for logging to work correctly.

You can configure additional/alternate FileLog locations using CakeLog::config(). FileLog accepts a path which allows for custom paths to be used.

CakeLog::config('custom_path', array(
    'engine' => 'FileLog',
    'path' => '/path/to/custom/place/'

Creating and configuring log streams

Log stream handlers can be part of your application, or part of plugins. If for example you had a database logger called DataBaseLogger as part of your application it would be placed in app/libs/log/data_base_logger.php; as part of a plugin it would be placed in app/plugins/my_plugin/libs/log/data_base_logger.php. When configured, CakeLog will attempt to load. Configuring log streams is done by calling CakeLog::config(). Configuring our DataBaseLogger would look like

//for app/libs
CakeLog::config('otherFile', array(
    'engine' => 'DataBaseLogger',
    'model' => 'LogEntry',

//for plugin called LoggingPack
CakeLog::config('otherFile', array(
    'engine' => 'LoggingPack.DataBaseLogger',
    'model' => 'LogEntry',

When configuring a log stream the engine parameter is used to locate and load the log handler. All of the other configuration properties are passed to the log stream’s constructor as an array.

class DataBaseLogger {
    function __construct($options = array()) {

CakePHP has no requirements for Log streams other than that they must implement a write method. This write method must take two parameters $type, $message in that order. $type is the string type of the logged message, core values are error, warning, info and debug. In addition you can define your own types by using them when you call CakeLog::write.

It should be noted that you will encounter errors when trying to configure application level loggers from app/config/core.php. This is because paths are not yet bootstrapped. Configuring of loggers should be done in app/config/bootstrap.php to ensure classes are properly loaded.

Interacting with log streams

You can introspect the configured streams with CakeLog::configured(). The return of configured() is an array of all the currently configured streams. You can remove streams using CakeLog::drop($key). Once a log stream has been dropped it will no longer receive messages.

Error logging

Errors are now logged when Configure::write('debug', 0);. You can use Configure::write('log', $val), to control which errors are logged when debug is off. By default all errors are logged.

Configure::write('log', E_WARNING);

Would log only warning and fatal errors. Setting Configure::write('log', false); will disable error logging when debug = 0.