[mkurz]

• Backport of Allow turning evolutions script generation on or off per Ebean server #901 to 8.x.

Turn evolutions script generation on or off per Ebean server

play.ebean.generateEvolutionsScripts turns the generation of the evolutions scripts (conf/evolutions/<server>/1.sql, in dev and test mode) on or off for all Ebean servers. The new play.ebean.db.<server>.generateEvolutionsScripts setting overrides it for a single Ebean server, in both directions:

# Don't generate the scripts of the Ebean servers...
play.ebean.generateEvolutionsScripts = false
# ...except the one of the "default" Ebean server
play.ebean.db.default.generateEvolutionsScripts = true

For example, for:

• a read-only database used as its own Ebean server (EbeanPlugin: Add support for read-only data-sources #118)
• a database whose evolutions come from the classpath (e.g. from a dependency): Play's evolutions reader looks for conf/evolutions/<name>/1.sql on the filesystem first, so a generated file shadows these scripts
• a database to which Play shouldn't apply evolutions (play.evolutions.db.<name>.enabled = false), but whose generated script is still wanted, e.g. for a DBA

That's why the setting is independent of Play's play.evolutions.db.<name>.enabled. Nothing changes unless the new setting is used.

Until now, the only per-database way was to remove the -- Created by Ebean DDL header from conf/evolutions/<name>/1.sql (or to create that file with other content), after which Play Ebean doesn't touch it anymore. The docs now explain both that and the new settings.

EbeanConfig gets a new generateEvolutionsScripts(String server) default method, which falls back to generateEvolutionsScripts(), so custom implementations keep working. DefaultEbeanConfig and EbeanParsedConfig keep their existing constructors.

Move the read replica setting to play.ebean.db.<server>

So that all settings of a single Ebean server live in one place, like Play's own play.evolutions.db.<name> settings, the read replica setting from #892 moves from play.ebean.readOnlyDatasources.<server> to play.ebean.db.<server>.readOnlyDatasource. It has not been released yet, so only snapshot users need to rename it.

Testing

• New EbeanEvolutionsScriptsTest with two Ebean servers, each with its own model: scripts get generated for both by default (with Play's evolutions disabled, so that's independent), for none when turned off globally, and selectively when overridden per server in either direction; an unknown Ebean server name fails at startup. The two per-server tests fail without the change. For this, the build now enhances the models of the tests too.
• New parsing tests in EbeanParsedConfigTest; EbeanReadOnlyDatasourceTest uses the renamed setting.
• The existing tests with an empty models list now turn off the script generation: without configured models, Ebean searches the classpath and would pick up the new test models, writing conf/evolutions/default/1.sql into the working directory.
• MiMa and the docs tests pass.

[mergify]

This pull request does not currently match the merge queue conditions, so it cannot be queued from here. The box comes back if it matches again.