Tables not getting created in multiple databases in spring boot application

Question

I am working on spring boot multi tenancy application. I have configured multi datasources as shown below :

application.properties

spring.multitenancy.datasource1.url=jdbc:mysql://localhost:3306/db1
spring.multitenancy.datasource1.username=root
spring.multitenancy.datasource1.password=****
spring.multitenancy.datasource1.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update

spring.multitenancy.datasource2.url=jdbc:mysql://localhost:3306/db2
spring.multitenancy.datasource2.username=root
spring.multitenancy.datasource2.password=****
spring.multitenancy.datasource2.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update

spring.multitenancy.datasource3.url=jdbc:mysql://localhost:3306/db3
spring.multitenancy.datasource3.username=root
spring.multitenancy.datasource3.password=****
spring.multitenancy.datasource3.driver-class-name=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update

DataSourceBasedMultiTenantConnectionProviderImpl.java

@Component
public class DataSourceBasedMultiTenantConnectionProviderImpl extends AbstractDataSourceBasedMultiTenantConnectionProviderImpl {

    private static final long serialVersionUID = 8168907057647334460L;
    private static final String DEFAULT_TENANT_ID = "tenant_1";

    @Autowired
    private DataSource dataSource1;

    @Autowired
    private DataSource dataSource2;

    @Autowired
    private DataSource dataSource3;

    private Map<String, DataSource> map;

    @PostConstruct
    public void load() {
        map = new HashMap<>();
        map.put("tenant_1", dataSource1);
        map.put("tenant_2", dataSource2);
        map.put("tenant_3", dataSource3);
    }

    @Override
    protected DataSource selectAnyDataSource() {
        return map.get(DEFAULT_TENANT_ID);
    }

    @Override
    protected DataSource selectDataSource(String tenantIdentifier) {
        return map.get(tenantIdentifier);
    }
}

MultitenancyProperties.java

@ConfigurationProperties("spring.multitenancy")
public class MultitenancyProperties {

    @NestedConfigurationProperty
    private DataSourceProperties datasource1;

    @NestedConfigurationProperty
    private DataSourceProperties datasource2;

    @NestedConfigurationProperty
    private DataSourceProperties datasource3;

    public DataSourceProperties getDatasource1() {
        return datasource1;
    }

    public void setDatasource1(DataSourceProperties datasource1) {
        this.datasource1 = datasource1;
    }

    public DataSourceProperties getDatasource2() {
        return datasource2;
    }

    public void setDatasource2(DataSourceProperties datasource2) {
        this.datasource2 = datasource2;
    }

    public DataSourceProperties getDatasource3() {
        return datasource3;
    }

    public void setDatasource3(DataSourceProperties datasource3) {
        this.datasource3 = datasource3;
    }
}

MultiTenancyJpaConfiguration.java

@Configuration
@EnableConfigurationProperties(JpaProperties.class)
public class MultiTenancyJpaConfiguration {

    @Autowired
    private DataSource dataSource;

    @Autowired
    private JpaProperties jpaProperties;

    @Autowired
    private MultiTenantConnectionProvider multiTenantConnectionProvider;

    @Autowired
    private CurrentTenantIdentifierResolver currentTenantIdentifierResolver;

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(EntityManagerFactoryBuilder builder) {
        Map<String, Object> hibernateProps = new LinkedHashMap<>();
        hibernateProps.putAll(jpaProperties.getHibernateProperties(dataSource));

        hibernateProps.put(Environment.MULTI_TENANT, MultiTenancyStrategy.DATABASE);
        hibernateProps.put(Environment.MULTI_TENANT_CONNECTION_PROVIDER, multiTenantConnectionProvider);
        hibernateProps.put(Environment.MULTI_TENANT_IDENTIFIER_RESOLVER, currentTenantIdentifierResolver);
        hibernateProps.put(Environment.DIALECT, "org.hibernate.dialect.MySQLDialect");

        return builder.dataSource(dataSource).packages(HotelEntity.class.getPackage().getName()).properties(hibernateProps).jta(false).build();
    }
}

Application launcher

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableConfigurationProperties(MultitenancyProperties.class)
public class Application {

    public static void main(String[] args) {
        ApplicationContext ctx = SpringApplication.run(Application.class, args);
    }
}

When I run the boot application, all tables are created in only first data source.
1) How can I create tables in all data sources on application startup?
2) How to see connections opened/closed for each of the data sources?
3) Is there a better way of configuring multi tenancy application using spring boot for better performance?

Answer 1

Try adding the following properties:

spring.jpa.generate-ddl=true

Answer 2

As @Alex said, you need differnt EntityManagers, TransactionManager and Datasources. Here is how I would do it

@Configuration
@EnableJpaRepositories(
    entityManagerFactoryRef = "dataSource1EntityManagerFactory",
    transactionManagerRef = "dataSource1TransactionManager",
    basePackageClasses = dataSource1Repository.class)
public class DataSource1Config extends SqlConfig{// Put all common code in base class SqlConfig. If not remove it

    @Bean
    @Primary
    public DataSource dataSource1() {
        //create dataSource using MultitenancyProperties::getDataSource1
    }

    @Primary
    @Bean(name = "dataSource1TransactionManager")
    PlatformTransactionManager dataSource1TransactionManager(EntityManagerFactory dataSource1EntityManagerFactory) {
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(dataSource1EntityManagerFactory);
        return txManager;
    }

    @Primary
    @Bean(name = "dataSource1EntityManagerFactory")
    LocalContainerEntityManagerFactoryBean dataSource1EntityManagerFactory() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource1());
        em.setPackagesToScan(dataSource1Repository.class.getPackage().getName(), dataSource1ModelClass.class.getPackage().getName());
        em.setPersistenceUnitName("dataSource1Db");

        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(false);
        em.setJpaVendorAdapter(vendorAdapter);
        return em;
    }
}

You can create two other classes like this. Remember to use @Primary on only one instace of datasource, transactionmanger and entitymanager(doesn't matter which one). Another word of caution, make sure Repository classes are in different packages for all three databases.