Server-less architectures where as a developer you deploy functions that are fully managed by the Cloud environment and are executed in ephemeral processes require a unique approach. Traditional frameworks like Grails and Spring are not really suitable since low memory consumption and fast startup time are critical and the Function as a Service (FaaS) server will typically spin up your function for a period using a cold start and then keep it warm. This session introduces Micronaut’s compile-time approach: fast startup time and low-memory footprint which make it a great candidate for using as a framework for developing functions. In fact, Micronaut features dedicated support for developing and deploying functions to AWS Lambda and any FaaS system that supports running functions as containers (such as OpenFaaS, Rift, or Fn).

1. Serverless functions
with Micronaut
Álvaro Sánchez-Mariscal
@alvaro_sanchez

2. About me
— Coming from Madrid
!
— Developer since 2001 (Java / Spring stack).
— Former BEA Systems
⚰
and Sun Microsystems
— Founded Salenda in 2007. Left in 2013.
— Working @ OCI since 2015: Groovy, Grails & Micronaut!
— Speaker at conferences like Devoxx, GeeCON,
JavaLand, JavaZone, Codemotion and Spring IO.
! % & ' ( ) * + , -
@alvaro_sanchez

3. Introducing

4. @alvaro_sanchez

5. Introducing Micronaut
The productivity of Spring Boot / Grails with a
compile-time, non-blocking performance.
— Designed from the ground up with microservices and
the cloud in mind ("Natively Cloud Native").
— Ultra-lightweight and Reactive (based on Netty)
— Integrated AOP and Compile-Time DI for Java, Groovy
and Kotlin.
@alvaro_sanchez

6. Hello, Galaxy!
interface HelloApi {
@Get("/hello") String hello();
}
@Controller("/")
class HelloServer implements HelloApi {
@Get("/hello")
public String hello() {
return "Hello, Galaxy!";
}
}
@Client("/") // Client Generated at Compile Time
interface HelloClient extends HelloApi {}
@alvaro_sanchez

7. Hello, Galaxy!
@MicronautTest
class ApplicationTest {
@Inject
HelloClient helloClient;
@Test
void testHello() {
Assertions.assertEquals("Hello, Galaxy!", helloClient.hello());
}
}
@alvaro_sanchez

8. Natively Cloud Native
— Service Discovery - Consul, Eureka, Route 53 and
Kubernetes.
— Configuration Sharing - Consul Supported and
Amazon ParameterStore planned.
— Client Side Load Balancing - Integrated or Netflix
Ribbon Supported
— Distributed tracing - Zipkin or Jaeger.
— Support for Serverless Computing; AWS Lambda,
@alvaro_sanchez

9. Ge!ing started
$ curl -s "https://get.sdkman.io" | bash
$ sdk install micronaut
$ mn create-function uppercase
| Generating Java project...
| Function created at /tmp/uppercase
@alvaro_sanchez

10. Ge!ing started: @FunctionBean
import io.micronaut.function.FunctionBean;
import java.util.function.Function;
@FunctionBean("isbn-validator")
public class IsbnValidatorFunction
implements Function<IsbnValidationRequest, IsbnValidationResponse> {
@Override
public IsbnValidationResponse apply(IsbnValidationRequest request) {
return new IsbnValidationResponse(); //do stuff
}
}
@alvaro_sanchez

11. Ge!ing started: @FunctionBean
— Use Java 8's java.util.function.*:
— Supplier<O>: no arguments, single result.
— Consumer<I>: single argument, no result.
— BiConsumer<I, J>: two arguments, no result.
— Function<I, O>: single argument, single result.
— Function<I, J, O>: two arguments, single result.
@alvaro_sanchez

12. Ge!ing started: @Factory
@Factory
public class WordFunctions {
@FunctionBean("uppercase")
public Function<String, String> uppercase() {
return String::toUpperCase;
}
@FunctionBean("lowercase")
public Function<String, String> lowercase() {
return String::toLowerCase;
}
}
@alvaro_sanchez

13. Ge!ing started: Groovy
//src/main/groovy/com/acme/HelloFunction.groovy
import groovy.transform.Field
import javax.inject.Inject
@Field @Inject HelloService helloService
String hello(String name) {
helloService.hello(name)
}
@alvaro_sanchez

14. Testing functions
— Micronaut can expose functions as local REST
endpoints.
— @FunctionClient can be leveraged in tests:
@FunctionClient
public interface IsbnValidatorClient {
@Named("isbn-validator")
@Retryable(attempts = "5", delay = "5s")
Single<IsbnValidationResponse> validate(@Body IsbnValidationRequest req);
}
@alvaro_sanchez

15. Invoking remote functions
— The same @FunctionClient can invoke remote
functions:
# src/main/resources/application.yml
aws:
lambda:
functions:
slack:
functionName: slack-message
region: eu-west-1
@alvaro_sanchez

16. Functions as CLI applications
— The build is configured to produce runnable JARs:
$ echo '{value: 3}' | java -jar build/libs/math-function-0.1-all.jar
— This allows functions written with Micronaut to be
deployed to platforms that process standard input/
output, such as OpenFaaS.
@alvaro_sanchez

17. GraalVM
— New Polyglot VM from Oracle.
— Runs JS, Java, Ruby, R etc.
— Ability to turn Java code into native images.
— Can run Micronaut applications and functions
blazingly fast!
@alvaro_sanchez

18. Demo

20. Q & A
Álvaro Sánchez-Mariscal
@alvaro_sanchez