Add unit tests for api

**Feature request**
It would be great to have logging for services.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_logging` with default `false`.

Start by locating the API configuration entry point and any existing unit-test files for API behavior. Check how configuration defaults are represented and how services currently handle output; done should include coverage for the default-disabled option and the logging behavior, once that behavior is defined.

Written by the indexing model from the issue text.