Multiple datasources spring boot

Question

I have tried for literally hours to get this working, looking at the docs:

https://docs.spring.io/spring-boot/docs/current/reference/html/howto-data-access.html

...various stackoverflow questions and as much other stuff as I can find. But, this is proving elusive (read, making me want to bash my head against a wall). Any help would be so, so welcome!

I need to connect to two different databases (sounds simple enough?) and I have a Spring Boot web application using the spring-boot-starter-data-jpa dependency which got things off the ground very nicely with a single data source. Now I need to talk to a second database and things have not been working. I thought I had it working for a while, but it turned out that everything was going to the primary database.

I'm currently trying to get this working on a separate 'cut down' project to try and reduce the number of moving parts, still not working though.

I have two @Configuration classes - one for each data source, here's the first:

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "firstEntityManagerFactory",
        transactionManagerRef = "firstTransactionManager",
        basePackages = {"mystuff.jpaexp.jpatest"})
public class DataConfiguration {
    @Bean
    @Primary
    @ConfigurationProperties(prefix = "app.datasource1")
    public DataSourceProperties firstDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @Primary
    @ConfigurationProperties("app.datasource1")
    public DataSource firstDataSource() {
        return firstDataSourceProperties().initializeDataSourceBuilder().
                driverClassName("org.postgresql.Driver").
                url("jdbc:postgresql://localhost:5432/experiment1").
                username("postgres").
                password("postgres").
                build();
    }

    @Primary
    @Bean
    public LocalContainerEntityManagerFactoryBean firstEntityManagerFactory() {
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);

        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setPackagesToScan("mystuff.jpaexp.jpatest");
        factory.setDataSource(firstDataSource());
        factory.setPersistenceUnitName("ds1");
        return factory;
    }

    @Primary
    @Bean
    public PlatformTransactionManager firstTransactionManager() {
        return new JpaTransactionManager();
    }
}

and here's the second:

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "secondEntityManagerFactory",
        transactionManagerRef = "secondTransactionManager",
        basePackages = {"mystuff.jpaexp.jpatest2"})
public class Otherconfiguration {
    @Bean
    @ConfigurationProperties(prefix = "app.datasource2")
    public DataSourceProperties secondDataSourceProperties() {
        return new DataSourceProperties();
    }

    @Bean
    @ConfigurationProperties("app.datasource2")
    public DataSource secondDataSource() {
        return secondDataSourceProperties().initializeDataSourceBuilder().
                driverClassName("org.postgresql.Driver").
                url("jdbc:postgresql://localhost:5432/experiment2").
                username("postgres").
                password("postgres").
                build();
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory() {
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        vendorAdapter.setGenerateDdl(true);

        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(vendorAdapter);
        factory.setPackagesToScan("mystuff.jpaexp.jpatest2");
        factory.setDataSource(secondDataSource());
        factory.setPersistenceUnitName("ds2");
        return factory;
    }

    @Bean
    public PlatformTransactionManager secondTransactionManager() {
        return new JpaTransactionManager();
    }
}

In each of the two packages mystuff.jpaexp.jpatest and mystuff.jpaexp.jpatest2 I have a simple @Entity and CrudRepository that should go together with the first and second datasources respectively.

I then have a main() to test things out:

@SpringBootApplication
@EnableAutoConfiguration(exclude = {WebMvcAutoConfiguration.class})
@ComponentScan("mystuff.jpaexp.*")
public class SpringbootCommandLineApp implements CommandLineRunner {
    private final MyRepository myRepository;
    private final OtherRepo otherRepo;

    @Autowired
    public SpringbootCommandLineApp(MyRepository myRepository, OtherRepo otherRepo) {
        this.myRepository = myRepository;
        this.otherRepo = otherRepo;
    }

    public static void main(String[] args) {
        new SpringApplicationBuilder(SpringbootCommandLineApp.class)
                .web(false)
                .run(args);
    }

    @Override
    public void run(String... args) throws Exception {
        myRepository.save(new MyEntity("Goodbye or hello"));
        myRepository.save(new MyEntity("What?"));
        myRepository.save(new MyEntity("1,2,3..."));

        myRepository.findAll().forEach(System.out::println);

        otherRepo.save(new MyEntity2("J Bloggs"));
        otherRepo.save(new MyEntity2("A Beecher"));
        otherRepo.save(new MyEntity2("C Jee"));

        otherRepo.findAll().forEach(x -> {
            System.out.println("Name:" + x.getName() + ", ID: " + x.getId());
        });
    }
}

And lastly, some props in application.properties:

app.datasource1.driver-class-name=org.postgresql.Driver
app.datasource1.url=jdbc:postgresql://localhost:5432/experiment1
app.datasource1.username=postgres
app.datasource1.password=postgres

app.datasource2.driver-class-name=org.postgresql.Driver
app.datasource2.url=jdbc:postgresql://localhost:5432/experiment2
app.datasource2.username=postgres
app.datasource2.password=postgres

These have absolutely no effect -- things appear to still be configured by spring.datasource.* instead, which is obviously no use.

Final output:

2018-05-25 17:04:00.797  WARN 29755 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
2018-05-25 17:04:00.800  INFO 29755 --- [           main] utoConfigurationReportLoggingInitializer : 

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-05-25 17:04:00.803 ERROR 29755 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Cannot determine embedded database driver class for database type NONE

Action:

If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).


Process finished with exit code 1

I know there's a lot of code here, sorry and thanks!

Answer 1

Well, it took a long time, I think there were multiple subtle problems and also some bits that could be simplified a little:

• Only one DataSourceProperties was required - both datasources can use it
• @ConfigurationProperties is needed on the DataSource bean definition, not the DataSourceProperties bean
• I think the @ComponentScan("mystuff.jpaexp.*") annotation was incorrect, and replacing this with simply @ComponentScan seemed to fix picking up of some of the bean definitions
• I had to inject an EntityManagerFactor into the JpaTransactionManager definition: return new JpaTransactionManager(secondEntityManagerFactory().getObject());
• I added a JpaProperties bean, and explicity pulled those properties into a VendorAdapter

The VendorAdapter/JpaProperties changes looked like this (it seems odd that JpaProperties is vendor-independent yet it has a hibernateProperties on it?!):

@Bean
public LocalContainerEntityManagerFactoryBean secondEntityManagerFactory() {
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(true);

    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    factory.setPackagesToScan("...entity-package...");
    factory.setDataSource(secondDataSource());
    Map<String, String> props = new HashMap<>();
    props.putAll(secondJpaProperties().getProperties());
    props.putAll(secondJpaProperties().getHibernateProperties(secondDataSource()));
    factory.setJpaPropertyMap(props);
    factory.setPersistenceUnitName("ds2");
    return factory;
}

@Bean
@ConfigurationProperties(prefix = "jpa.datsource2")
public JpaProperties secondJpaProperties() {
    return new JpaProperties();
}

I think this was enough to get things going. In addition, the ever-so-clever defaulting of various properties to make an embedded H2 instance spring to life, no longer worked, so I also had to be explicit about all the DB properties:

jpa.datasource1.hibernate.ddl-auto=create
app.datasource1.driver-class-name=org.h2.Driver
app.datasource1.url=jdbc:h2:mem:primary
app.datasource1.username=
app.datasource1.password=

jpa.datasource2.hibernate.ddl-auto=create
app.datasource2.driver-class-name=org.h2.Driver
app.datasource2.url=jdbc:h2:mem:view
app.datasource2.username=
app.datasource2.password=