Logger

API reference › yii › log › Logger

class	yii\log\Logger
Extends	yii\base\Component » yii\base\BaseObject
Implements	yii\base\Configurable
Since	2.0
Source	framework/log/Logger.php

Logger records logged messages in memory and sends them to different targets if $dispatcher is set.

A Logger instance can be accessed via Yii::getLogger(). You can call the method log() to record a single log message. For convenience, a set of shortcut methods are provided for logging messages of various severity levels via the Yii class:

• Yii::trace()
• Yii::error()
• Yii::warning()
• Yii::info()
• Yii::beginProfile()
• Yii::endProfile()

For more details and usage information on Logger, see the guide article on logging.

When the application ends or $flushInterval is reached, Logger will call flush() to send logged messages to different log targets, such as file, email, or database, with the help of the $dispatcher.

Properties

Property	Type	Description	Defined by
$behaviors read-only	array<yii\base\Behavior<static>>	List of behaviors attached to this component.	yii\base\Component
$dbEventNames	array	Of event names used to get statistical results of DB queries. Default: ['yii\db\Command::query', 'yii\db\Command::execute']. Available since 2.0.41.	Logger
$dbProfiling read-only	array{int, int|float}	The first element indicates the number of SQL statements executed, and the second element the total time spent in SQL execution.	Logger
$dispatcher	Dispatcher	The message dispatcher. Default: null.	Logger
$elapsedTime read-only	float	The total elapsed time in seconds for current request.	Logger
$flushInterval	int	How many messages should be logged before they are flushed from memory and sent to targets. Default: 1000.	Logger
$messages	array<int|string, yii\log\LogMessage>	Logged messages. Default: [].	Logger
$profiling read-only	list<yii\log\ProfilingTiming>	The profiling results.	Logger
$profilingAware	bool	Whether the profiling-aware mode should be switched on. Default: false. Available since 2.0.43.	Logger
$traceLevel	int	How much call stack information (file name and line number) should be logged for each message. Default: 0.	Logger

Methods

Method	Description	Defined by
__construct()	Constructor.	yii\base\BaseObject
__call()	Calls the named method which is not a class method.	yii\base\Component
__clone()	This method is called after the object is created by cloning an existing one.	yii\base\Component
__get()	Returns the value of a component property.	yii\base\Component
__isset()	Checks if a property is set, i.e. defined and not null.	yii\base\Component
__set()	Sets the value of a component property.	yii\base\Component
__unset()	Sets a component property to be null.	yii\base\Component
attachBehavior()	Attaches a behavior to this component.	yii\base\Component
attachBehaviors()	Attaches a list of behaviors to the component.	yii\base\Component
behaviors()	Returns a list of behaviors that this component should behave as.	yii\base\Component
calculateTimings()	Calculates the elapsed time for the given log messages.	Logger
canGetProperty()	Returns a value indicating whether a property can be read.	yii\base\Component
canSetProperty()	Returns a value indicating whether a property can be set.	yii\base\Component
className() static	Returns the fully qualified name of this class.	yii\base\BaseObject
detachBehavior()	Detaches a behavior from the component.	yii\base\Component
detachBehaviors()	Detaches all behaviors from the component.	yii\base\Component
ensureBehaviors()	Makes sure that the behaviors declared in behaviors() are attached to this component.	yii\base\Component
flush()	Flushes log messages from memory to targets.	Logger
getBehavior()	Returns the named behavior object.	yii\base\Component
getBehaviors()	Returns all behaviors attached to this component.	yii\base\Component
getDbProfiling()	Returns the statistical results of DB queries.	Logger
getElapsedTime()	Returns the total elapsed time since the start of the current request.	Logger
getLevelName() static	Returns the text display of the specified level.	Logger
getProfiling()	Returns the profiling results.	Logger
hasEventHandlers()	Returns a value indicating whether there is any handler attached to the named event.	yii\base\Component
hasMethod()	Returns a value indicating whether a method is defined.	yii\base\Component
hasProperty()	Returns a value indicating whether a property is defined for this component.	yii\base\Component
init()	Initializes the logger by registering flush() as a shutdown function.	Logger
log()	Logs a message with the given type and category.	Logger
off()	Detaches an existing event handler from this component.	yii\base\Component
on()	Attaches an event handler to an event.	yii\base\Component
trigger()	Triggers an event.	yii\base\Component

Constants

Constant	Value	Description	Defined by
LEVEL_ERROR	0x1	Error message level. An error message is one that indicates the abnormal termination of the application and may require developer’s handling.	Logger
LEVEL_WARNING	0x2	Warning message level. A warning message is one that indicates some abnormal happens but the application is able to continue to run. Developers should pay attention to this message.	Logger
LEVEL_INFO	0x4	Informational message level. An informational message is one that includes certain information for developers to review.	Logger
LEVEL_TRACE	0x8	Tracing message level. A tracing message is one that reveals the code execution flow.	Logger
LEVEL_PROFILE	0x40	Profiling message level. This indicates the message is for profiling purpose.	Logger
LEVEL_PROFILE_BEGIN	0x50	Profiling message level. This indicates the message is for profiling purpose. It marks the beginning of a profiling block.	Logger
LEVEL_PROFILE_END	0x60	Profiling message level. This indicates the message is for profiling purpose. It marks the end of a profiling block.	Logger

Property details

$flushInterval

public int $flushInterval = 1000

How many messages should be logged before they are flushed from memory and sent to targets.

Defaults to 1000, meaning the flush() method will be invoked once every 1000 messages logged. Set this property to be 0 if you don’t want to flush messages until the application terminates. This property mainly affects how much memory will be taken by the logged messages. A smaller value means less memory, but will increase the execution time due to the overhead of flush().

$messages

public array<int|string, yii\log\LogMessage> $messages = []

Logged messages.

This property is managed by log() and flush(). Each log message is of the following structure:

[
  [0] => message (mixed, can be a string or some complex data, such as an exception object)
  [1] => level (integer)
  [2] => category (string)
  [3] => timestamp (float, obtained by microtime(true))
  [4] => traces (array, debug backtrace, contains the application code call stacks)
  [5] => memory usage in bytes (int, obtained by memory_get_usage()), available since version 2.0.11.
]

$profiling

public list<yii\log\ProfilingTiming> $profiling

The profiling results.

Each element is an array consisting of these elements: info, category, timestamp, trace, level, duration, memory, memoryDiff. The memory and memoryDiff values are available since version 2.0.11.

Access

Read-only (virtual property).

$profilingAware

public bool $profilingAware = false

Whether the profiling-aware mode should be switched on.

If on, flush() makes sure that profiling blocks are flushed in pairs. In case that any dangling messages are detected these are kept for the next flush interval to find their pair. To prevent memory leaks, when number of dangling messages reaches flushInterval value, logger flushes them immediately and triggers a warning. Keep in mind that profiling-aware mode is more time and memory consuming.

Since

2.0.43

$traceLevel

public int $traceLevel = 0

How much call stack information (file name and line number) should be logged for each message.

If it is greater than 0, at most that number of call stacks will be logged. Note that only application call stacks are counted.

Method details

calculateTimings()

public function calculateTimings(array<int|string, yii\log\LogMessage> $messages): list<yii\log\ProfilingTiming>

Calculates the elapsed time for the given log messages.

Parameters

Parameter	Type	Description
$messages	array<int|string, yii\log\LogMessage>	The log messages obtained from profiling

Returns

list<yii\log\ProfilingTiming>: Timings. Each element is an array consisting of these elements: info, category, timestamp, trace, level, duration, memory, memoryDiff. The memory and memoryDiff values are available since version 2.0.11.

flush()

public function flush(bool $final = false): mixed

Flushes log messages from memory to targets.

Parameters

Parameter	Type	Description
$final	bool	Whether this is a final call during a request.

Returns

mixed

getDbProfiling()

public function getDbProfiling(): array{int, int|float}

Returns the statistical results of DB queries.

The results returned include the number of SQL statements executed and the total time spent.

Returns

array{int, int|float}: The first element indicates the number of SQL statements executed, and the second element the total time spent in SQL execution.

getElapsedTime()

public function getElapsedTime(): float

Returns the total elapsed time since the start of the current request.

This method calculates the difference between now and the timestamp defined by constant YII_BEGIN_TIME which is evaluated at the beginning of BaseYii class file.

Returns

float: The total elapsed time in seconds for current request.

getLevelName()

public static function getLevelName(int $level): string

Returns the text display of the specified level.

Parameters

Parameter	Type	Description
$level	int	The message level, e.g. LEVEL_ERROR, LEVEL_WARNING.

Returns

string: The text display of the level

getProfiling()

public function getProfiling(list<string> $categories = [], list<string> $excludeCategories = []): list<yii\log\ProfilingTiming>

Returns the profiling results.

By default, all profiling results will be returned. You may provide $categories and $excludeCategories as parameters to retrieve the results that you are interested in.

Parameters

Parameter	Type	Description
$categories	list<string>	List of categories that you are interested in. You can use an asterisk at the end of a category to do a prefix match. For example, ‘yii\db*’ will match categories starting with ‘yii\db’, such as ‘yii\db\Connection’.
$excludeCategories	list<string>	List of categories that you want to exclude

Returns

list<yii\log\ProfilingTiming>: The profiling results. Each element is an array consisting of these elements: info, category, timestamp, trace, level, duration, memory, memoryDiff. The memory and memoryDiff values are available since version 2.0.11.

init()

public function init(): mixed

Initializes the logger by registering flush() as a shutdown function.

Returns

mixed

log()

public function log(string|array|Throwable|yii\log\PsrMessage $message, int $level, string $category = 'application'): mixed

Logs a message with the given type and category.

If $traceLevel is greater than 0, additional call stack information about the application code will be logged as well.

Parameters

Parameter	Type	Description
$message	string|array|Throwable|PsrMessage	The message to be logged. This can be a simple string or a more complex data structure that will be handled by a log target.
$level	int	The level of the message. This must be one of the following: Logger::LEVEL_ERROR, Logger::LEVEL_WARNING, Logger::LEVEL_INFO, Logger::LEVEL_TRACE, Logger::LEVEL_PROFILE, Logger::LEVEL_PROFILE_BEGIN, Logger::LEVEL_PROFILE_END.
$category	string	The category of the message.

Returns

mixed