Debugging servers

When dealing with multiple endpoints, how to find out which endpoint handled a request, or why an endpoint didn’t handle a request?

For this purpose, tapir provides optional logging. The logging options (and messages) can be customised by changing the default LogRequestHandling class, which is part of server options.

The following can be customised:

  1. logWhenHandled: when a request is handled by an endpoint, or when the inputs can’t be decoded, and the decode failure maps to a response (default: true, DEBUG log)
  2. logAllDecodeFailures: when the inputs can’t be decoded, and the decode failure doesn’t map to a response (the next endpoint will be tried; default: false, DEBUG log)
  3. logLogicExceptions: when there’s an exception during evaluation of the server logic (default: true, ERROR log)

Logging all decode failures (2) might be helpful when debugging, but can also produce a large amount of logs, hence it’s disabled by default.

Even if logging for a particular category (as described above) is set to true, normal logger rules apply - if you don’t see the logs, please verify your logging levels for the appropriate packages.