Micronaut Integration in Grails 6

Micronaut and Grails

Starting with Grails 5, the framework is built on the Micronaut Foundation. This integration brings Micronaut's compile-time dependency injection, smaller memory footprint, and GraalVM native image support to Grails applications.

Key Benefits

• Compile-time DI - No reflection, faster startup
• Smaller memory footprint - Better for containers and serverless
• GraalVM support - Native image compilation
• Micronaut modules - Direct access to Micronaut ecosystem

Using Micronaut Features

// Micronaut HTTP client in a Grails service
@Singleton
class ExternalApiService {

    @Inject
    @Client("https://api.example.com")
    HttpClient client

    def fetchData() {
        client.toBlocking().retrieve('/data')
    }
}

Micronaut Data

While GORM remains the primary data access layer, Micronaut Data provides an alternative with compile-time query derivation:

@JdbcRepository(dialect = Dialect.MYSQL)
interface BookRepository extends CrudRepository<Book, Long> {
    List<Book> findByAuthor(String author)
}

Configuration

Micronaut configuration integrates seamlessly with Grails:

# application.yml
micronaut:
  application:
    name: myapp
  server:
    port: 8080

Key Points

• Grails 6 is built on Micronaut Foundation for performance.
• Compile-time dependency injection eliminates reflection overhead.
• Micronaut modules (HTTP client, data) are available directly.
• GraalVM native images enable near-instant startup.
• GORM remains the primary data access layer.