Description:

Zend\Log\Logger is a component for general purpose logging. It supports multiple
log backends, formatting messages sent to the log, and filtering messages from
being logged. These functions are divided into the following objects:

* A Logger (instance of Zend\Log\Logger) is the object that your application
uses the most. You can have as many Logger objects as you like; they do not
interact. A Logger object must contain at least one Writer, and can optionally
contain one or more Filters.
* A Writer (inherits from Zend\Log\Writer\AbstractWriter) is responsible for
saving data to storage.
* A Filter (implements Zend\Log\Filter\FilterInterface) blocks log data from
being saved. A filter is applied to an individual writer. Filters can be
chained.
* A Formatter (implements Zend\Log\Formatter\FormatterInterface) can format the
log data before it is written by a Writer. Each Writer has exactly one
Formatter.

Optional: MongoDB (php-pecl-mongo)