Multi-tenancy in Spring Boot

Introduction: Multitenancy is a powerful architectural concept that allows a single instance of an application to serve multiple clients, known as tenants, while keeping their data and configurations isolated from each other. In this article, we will explore how to implement multitenancy in a Spring Boot application. We will discuss different approaches and provide a sample code snippet to demonstrate the implementation.

Understanding Multitenancy: Multitenancy can be achieved through various strategies, such as separate databases, shared database with schema separation, or shared database with data segregation. In this example, we will focus on the approach of using a shared database with schema separation, where each tenant has its own dedicated database schema.

Sample Code Snippet:

@Configuration
public class MultitenancyConfig {
    
    @Bean
    public DataSource multitenantDataSource() {
        MultitenantDataSource dataSource = new MultitenantDataSource();
        
        // Configure your data source properties here
        
        return dataSource;
    }
    
    @Bean
    public MultiTenantConnectionProvider multiTenantConnectionProvider() {
        // Implement your own MultiTenantConnectionProvider
        // that provides tenant-specific database connections
        return new YourMultiTenantConnectionProvider();
    }
    
    @Bean
    public CurrentTenantIdentifierResolver currentTenantIdentifierResolver() {
        // Implement your own CurrentTenantIdentifierResolver
        // that resolves the current tenant identifier
        return new YourCurrentTenantIdentifierResolver();
    }
    
    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(
            DataSource dataSource,
            MultiTenantConnectionProvider multiTenantConnectionProvider,
            CurrentTenantIdentifierResolver currentTenantIdentifierResolver) {
        
        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
        emf.setDataSource(dataSource);
        emf.setPackagesToScan("com.your.package");
        
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        emf.setJpaVendorAdapter(vendorAdapter);
        
        Map<String, Object> properties = new HashMap<>();
        properties.put(org.hibernate.cfg.Environment.MULTI_TENANT, MultiTenancyStrategy.SCHEMA);
        properties.put(org.hibernate.cfg.Environment.MULTI_TENANT_CONNECTION_PROVIDER, multiTenantConnectionProvider);
        properties.put(org.hibernate.cfg.Environment.MULTI_TENANT_IDENTIFIER_RESOLVER, currentTenantIdentifierResolver);
        
        emf.setJpaPropertyMap(properties);
        
        return emf;
    }
    
    @Bean
    public JpaTransactionManager transactionManager(EntityManagerFactory emf) {
        return new JpaTransactionManager(emf);
    }
}

Conclusion: Implementing multitenancy in a Spring Boot application enables you to efficiently serve multiple clients while maintaining data isolation. In this article, we explored the approach of using a shared database with schema separation and provided a sample code snippet demonstrating the configuration required. Feel free to experiment with this code and adapt it to your specific requirements.