Idea for the API:

• Require starting Hibernate Search, which can be done offline, see https://docs.jboss.org/hibernate/stable/search/reference/en-US/html_single/#backend-elasticsearch-configuration-version and https://docs.jboss.org/hibernate/stable/search/reference/en-US/html_single/#mapper-orm-schema-management-strategy
• Add the feature to the schema manager

E.g. we’d add methods such as this one to the schema manager:

void exportSchema(Path targetDirectory);

And calling such methods would result in the creation of files in the given directory, with a predictable directory structure:

backend/indexes/MyEntity/index.json
backends/someNamedBackend/indexes/Foo/index.json

Of course the content of the export would be backend-specific; for Lucene, it would just do nothing (or maybe create the directory structure but leave a file for each index whose content says “the Lucene backend does not support exporting the schema”).

Later we might add more options (filtering, …) and features (export curl scripts, …), but let’s wait a bit before working on that: exporting json should be enough for most people.