When to use logging¶
You can access logging functionality by creating a logger via logger = getLogger(__name__), and then calling the loggerâs debug(), info(), warning(), error() and critical() methods. To determine when to use logging, and to see which logger methods to use when, see the table below. It states, for each of a set of common tasks, the best tool to use for that task.
| Task you want to perform | The best tool for the task |
|---|---|
| Display console output for ordinary usage of a command line script or program | print() |
| Report events that occur during normal operation of a program (e.g. for status monitoring or fault investigation) | A loggerâs info() (or debug() method for very detailed output for diagnostic purposes) |
| Issue a warning regarding a particular runtime event | warnings.warn() in library code if the issue is avoidable and the client application should be modified to eliminate the warning A loggerâs warning() method if there is nothing the client application can do about the situation, but the event should still be noted |
| Report an error regarding a particular runtime event | Raise an exception |
| Report suppression of an error without raising an exception (e.g. error handler in a long-running server process) | A loggerâs error(), exception() or critical() method as appropriate for the specific error and application domain |