PSR Log
An interface that describes a logger
.... The interfaces and classes described as well as relevant exception classes and a test suite to verify your implementation are provided as part of the psr/log package. Note that this is not a logger of its own. It is merely an interface that describes a logger. You can pick one of the implementations of the interface to get a logger. If you want to implement the interface, you can require this package and implement Psr\Log\LoggerInterface in your code.