Multiple datasources migrations using Flyway in a Spring Boot application

Question

We use Flyway for db migration in our Spring Boot based app and now we have a requirement to introduce multi tenancy support while using multiple datasources strategy. As pa

Answer 1

Having your same problem... I looked into the spring-boot-autoconfigure artifact for V 2.2.4 in the org.springframework.boot.autoconfigure.flyway package and I found an annotation FlywayDataSource.

Annotating ANY datasource you want to be used by Flyway should do the trick.
Something like this:

@FlywayDataSource
@Bean(name = "someDatasource")
public DataSource someDatasource(...) {
        <build and return your datasource>
}

Answer 2

Flyway supports migrations coded within Java and so you can start Flyway during your application startup.

https://flywaydb.org/documentation/migration/java

I am not sure how you would config Flyway to target a number of data sources via the its config files. My own development is based around using Java to call Flyway once per data source I need to work against. Spring Boot supports the autowiring of beans marked as @FlywayDataSource, but I have not looked into how this could be used.

For an in-java solution the code can be as simple as

    Flyway flyway = new Flyway();

    // Set the data source
    flyway.setDataSource(dataSource);

    // Where to search for classes to be executed or SQL scripts to be found
    flyway.setLocations("net.somewhere.flyway");

    flyway.setTarget(MigrationVersion.LATEST);
    flyway.migrate();

Answer 3

To make @Roger Thomas answer more the Spring Boot way:

Easiest solution is to annotate your primary datasource with @Primary (which you already did) and just let bootstrap migrate your primary datasource the 'normal' way.

For the other datasources, migrate those sources by hand:

@Configuration
public class FlywaySlaveInitializer {

     @Autowired private DataSource dataSource2;
     @Autowired private DataSource dataSource3;
     //other datasources

     @PostConstruct
     public void migrateFlyway() {
         Flyway flyway = new Flyway();
         //if default config is not sufficient, call setters here

         //source 2
         flyway.setDataSource(dataSource2);
         flyway.setLocations("db/migration_source_2");
         flyway.migrate();

         //source 3
         flyway.setDataSource(dataSource3);
         flyway.setLocations("db/migration_source_3");
         flyway.migrate();
     }
}

Answer 4

Found an easy solution for that - I added the step during the creation of my emf:

@Qualifier(EMF2)
@Bean(name = EMF2)
public LocalContainerEntityManagerFactoryBean entityManagerFactory2(
    final EntityManagerFactoryBuilder builder
) {
    final DataSource dataSource = dataSource2();
    Flyway.configure()
          .dataSource(dataSource)
          .locations("db/migration/ds2")
          .load()
          .migrate();
    return builder
        .dataSource(dataSource)
        .packages(Role.class)
        .properties(jpaProperties2().getProperties())
        .persistenceUnit("domain2")
        .build();
}

I disabled spring.flyway.enabled for that.

SQL files live in resources/db/migration/ds1/... and resources/db/migration/ds2/...