Support option to disable external access during CDS training

[making]

The following error occurred during CDS training in an app that uses spring-modulith-starter-jdbc (1.2).
This seems to be caused by opening a connection at runtime to determine the DatabaseType.
I haven't tried it with other modules, but I would like them to support CDS builds by adding an option such as -Dspring.flyway.enabled=false that does not make an external connection during CDS training, or, in the case of JDBC, an option to specify the DatabaseType statically.

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'databaseType' defined in class path resource [org/springframework/modulith/events/jdbc/JdbcEventPublicationAutoConfiguration.class]: Failed to instantiate [org.springframework.modulith.events.jdbc.DatabaseType]: Factory method 'databaseType' threw exception with message: Unsupported database type: UNKNOWN
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:648)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:636)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1355)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1185)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:522)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda-zsh(AbstractBeanFactory.java:337)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:335)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:975)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:971)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:625)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:456)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:335)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1363)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1352)
	at am.ik.note.NoteApiApplication.main(NoteApiApplication.java:10)
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.modulith.events.jdbc.DatabaseType]: Factory method 'databaseType' threw exception with message: Unsupported database type: UNKNOWN
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:178)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:644)
	... 19 more
Caused by: java.lang.IllegalArgumentException: Unsupported database type: UNKNOWN
	at org.springframework.modulith.events.jdbc.DatabaseType.lambda(DatabaseType.java:54)
	at java.base/java.util.Optional.orElseThrow(Unknown Source)
	at org.springframework.modulith.events.jdbc.DatabaseType.from(DatabaseType.java:54)
	at org.springframework.modulith.events.jdbc.JdbcEventPublicationAutoConfiguration.databaseType(JdbcEventPublicationAutoConfiguration.java:45)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:146)
	... 20 more

The current workaround is to add -Dspring.autoconfigure.exclude=org.springframework.modulith.events.jdbc.JdbcEventPublicationAutoConfiguration during training.

[odrotbohm]

Taking this to the team to decide about the best way forward.