(mongodb >=1.17.0)
Classes implementing this interface may be registered as a subscriber and receive log messages from the extension. This is similar to stream-based debug logging (i.e. mongodb.debug) except that trace-level log messages are not received.
As with stream-based logging, it is only possible to register a logger globally using MongoDB\Driver\Monitoring\addSubscriber(). The extension is not able to distinguish log messages for individual MongoDB\Driver\Manager objects.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_ERROR
Error log level. An error condition that the extension is unable to report through its API. This is the most severe log level in the extension.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_CRITICAL
Critical log level. An error condition with slightly less severity. This constant exists for consistency with libmongoc; however, the extension is unlikely to use it in practice.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_WARNING
Warning log level. Indicates a situation where undesirable application behavior may occur.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_MESSAGE
Message or notice log level. Indicates an event that is unusual but not problematic.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_INFO
Info log level. High-level information about normal driver behavior.
MongoDB\Driver\Monitoring\LogSubscriber::LEVEL_DEBUG
Debug log level. Detailed information that may be helpful when debugging an application.