How can I run Spring with MongoDB disabled, but still installed?

Question

I was reading through this Git issue: https://github.com/spring-projects/spring-boot/issues/7589 with regards to Java Spring boot and am trying to figure out a way to bypass

Answer 1

If your application behaves in such a way that MongoDB is optional, you have several options.

If you are migrating an existing application, the easiest from a start would be to exclude the auto-configuration and create the infrastructure yourself. Not in the way you've indicated as returning null from a @Bean method is quite nasty. Rather you could have some service that could lazily create the client and you could update your optional usages of MongoDB to go through that service. The service would be created regardless but would only create the underlying infrastructure if necessary.

The other option is to use a profile. If the main use case is that MongoDB is available then create a application-nomongo.properties (something like that) where you would exclude the auto-configuration using the spring.autoconfigure.exclude property. When the application starts without mongo, you can enable the nomongo profile and the auto-configuration will backoff. When it's not enabled, the Mongo bean will be created by Spring Boot.

Answer 2

I had the same issue. I want my application to be able to run offline as well, queue stuff and from time to time flush to database. This means it needs to be able to launch offline and connect whenever internet is available. Ofc, Spring crashed my app when it did not succeed in connecting. What worked for me was this:

@Configuration
@EnableJpaRepositories(bootstrapMode = BootstrapMode.LAZY)
public class DataSourceConfig {

@Bean(destroyMethod = "close")
public DataSource dataSource() {
    HikariConfig hikariConfig = new HikariConfig();
    hikariConfig.setDriverClassName("xxx");
    hikariConfig.setJdbcUrl("xxx");
    hikariConfig.setUsername("xxx");
    hikariConfig.setPassword("xxx");

    hikariConfig.setConnectionTestQuery("SELECT 1");
    hikariConfig.setPoolName("springHikariCP");
    hikariConfig.setInitializationFailTimeout(-1);

    hikariConfig.addDataSourceProperty("dataSource.cachePrepStmts", "true");
    hikariConfig.addDataSourceProperty("dataSource.prepStmtCacheSize", "250");
    hikariConfig.addDataSourceProperty("dataSource.prepStmtCacheSqlLimit", "2048");
    hikariConfig.addDataSourceProperty("dataSource.useServerPrepStmts", "true");
    HikariDataSource dataSource = new HikariDataSource(hikariConfig);

    return dataSource;
}

@Bean
public EntityManager entityManager() {
    return entityManagerFactory().getObject().createEntityManager();
}

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
    em.setDataSource(dataSource());
    em.setPackagesToScan("blabla");
    em.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
    em.setJpaProperties(additionalProperties());
    return em;
}

private Properties additionalProperties() {
    Properties properties = new Properties();
    properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL55Dialect");

    return properties;
}
}

Also, place this in your App class

@SpringBootApplication(exclude = HibernateJpaAutoConfiguration.class)

application.yml looks like this:

#Spring properties
spring:
  jpa:
    hibernate:
      ddl-auto: update
  datasource:
    url: "xxx"
    username: xxx
    password: xxx
    driver-class-name: com.mysql.cj.jdbc.Driver
    continue-on-error: true
  hikari:
    connection-timeout: 2000
    initialization-fail-timeout: -1
    auto-commit: true

This works for me, hopefully it will work for you guys as well, I saw many posts around here searching for a solution to this. Good luck!