The truth is painful. No matter how precisely your application is tested, your code will eventually fail at some point. This can be anything—unexpected exception, resource exhaustion, crash of some backing service, network outage, or simply an issue in the external library. Some of the possible issues (such as resource exhaustion) can be predicted and prevented in advance with proper monitoring. Unfortunately, there will always be something that passes your defenses, no matter how much you try.
What you can do instead is to prepare for such scenarios and make sure that no error passes unnoticed. In most cases, any unexpected failure scenario results in an exception raised by the application and logged through ...
