The SAS® Container Runtime (SCR) has many logging features as described in Understanding and Using Logging. While HTTP 5xx responses are logged by the container, I can find no option to enable status 4xx logging. Please create an environment variable to enable 4xx logging.
Setting LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_WEB_SERVLET_MVC_METHOD_ANNOTATION=DEBUG
comes close to the desired result, but unfortunately logs 200 responses as well as 400 and 500.
Allowing 4xx responses to be logged will speed up DEV debugging and greatly simplify our PROD alerting and monitoring. Please consider enabling this.