Java2 days 5_agile_steps_to_cloud-ready_apps
0 likes165 views
This document discusses 5 steps to building elastic and cloud-ready applications: 1. Use JCache for temporary caching to optimize reads and allow for scalable storage with distributed caches. 2. Choose a scalable runtime like Payara Micro that can run applications as executable JARs across multiple instances dynamically. 3. Design RESTful services APIs for client/server communication using JAX-RS. 4. Leverage messaging with CDI events within applications and potentially other technologies like JCA connectors for communication across services. 5. Abstract configuration with MicroProfile Configuration for pluggable, scoped configuration from various sources.
Java2 days 5_agile_steps_to_cloud-ready_apps
- 1. 5 Agile Steps to building Elastic and Cloud-ready apps Ondro Mihályi, Payara, http://www.payara.fish @OMIHALYI
- 2. @OMIHALYI What is cloud ready? ● Spring, Java EE / Jakarta EE, MicroProfile or Lagom ● AWS, Azure or Openshift ● SQL or NoSQL ● REST or EJB
- 3. @OMIHALYI Is it really about technology?
- 4. @OMIHALYI Even cool tech can be painful
- 5. Cloud ready requirements ● Pluggable persistence ● Scalable according to the load ● Low coupling There are even more according to the 12 factor applications manifesto ● External configuration ● Failure recovery ● Security ● Monitoring
- 7. @OMIHALYI Solution: agile evolution ● Simple API abstractions ● Flexible implementations ● Application logic first, against a solid platform ● Abstract the technology, prepare for refactoring ● Choose final technology later
- 10. @OMIHALYI JCache
- 11. @OMIHALYI JCache ● Temporary cache → optimize reads ● Cache data-retrieval method calls ● Temporary key-value store, extensible to permanent with a read/write-through policy ● More than 10 implementations (also in Payara Micro and Spring) ● Distributed caches allow scalable storage
- 12. @OMIHALYI JCache API @CacheResult User getUserForName(String name) { /*do if not cached*/ } @Inject Cache<String, User> users; users.put(user.getName(), user); User user = users.get(name); StreamSupport.stream(users.spliterator(), false) .filter( e -> e.getValue().getAge() > 50) .count()
- 13. @OMIHALYI JCache in your app container ● JCache widely available (in Payara Micro, Open Liberty, Spring Boot, …) ● In Java EE containers integrated with CDI ● Often powered by Hazelcast – Distributed, auto-discovery of nodes – Data replication, even data distribution – Lite nodes possible without data – More features via Hazelcast extensions
- 15. @OMIHALYI JCache
- 16. @OMIHALYI What is Payara Micro? ● Executable JAR (~70MB disk size, ~30 MB RAM) ● Runs WAR and EAR from command line – Also Uber JAR, embeddable (run from your app) ● Forms dynamically scalable cluster ● Web Profile "plus", MicroProfile ● Opensource, Maven dep, release each 3 months
- 17. @OMIHALYI ● Run multiple instances with the same command java -jar payara-micro.jar application.war --autoBindHttp ● Package as a single executable Uber JAR java -jar payara-micro.jar application.war --outputUberJar application.jar ● Run embedded: PayaraMicro.getInstance().bootStrap() ● Run using Maven plugin: mvn payara-micro:start Scale dynamically
- 18. @OMIHALYI What is MicroProfile? ● Project at Eclipse Foundation ● Common API, multiple implementations ● Extends Java EE ● Modern patterns: – Microservices, Reactive, … ● http://microprofile.io - open for everybody
- 19. @OMIHALYI
- 22. @OMIHALYI REST services API (server) ● JAX-RS endpoint @GET @Path("/{id}") @Produces(MediaType.APPLICATION_JSON) public User getUser(@PathParam("id") Integer id) { return userById(id); }
- 23. @OMIHALYI REST services API (client) ● JAX-RS client User user = client.target(url) .path("all") .request().get(User.class) ● MicroProfile client (much better abstraction) User admin = userService.getUser("admin")
- 24. @OMIHALYI JSON binding @JsonbNillable public class User implements Serializable { private String name; @JsonbTransient private String description; @JsonbProperty("userId") private long id; } - new in Java EE 8 and MicroProfile 2.0 More about JSON-B: http://json-b.net
- 26. @OMIHALYI CDI events, really? ● Part of Java EE API already ● Easy to send and observe messages ● Is it enough? What about: – Sending events to other services – Message broker to decouple services – Transactions
- 27. @OMIHALYI CDI events, really? What about: ● Sending events to other services – Nothing else is important in initial dev stage ● Message broker for reliable delivery ● Transactions
- 28. @OMIHALYI Payara CDI event bus ● Out of the box in Payara Micro ● Uses embedded Hazelcast ● No config needed, events dispatched to all matching services @Inject @Outbound Event<Payload> event; void onMessage( @Observes @Inbound Payload event)
- 29. @OMIHALYI Events as an abstraction ● Transfer events to other services in an event handler – Using distributed queues – Using any message broker ● Distribute incoming messages as events ● Start simple, extend to robust
- 30. @OMIHALYI One more option… JCA connector ● Message-driven beans, does it ring the bell? – Not only for JMS but for any messaging infrastructure ● Connetors on Github for AWS, Azure, Kafka, MQTT @MessageDriven(activationConfig = { … }) public class KafkaMDB implements KafkaListener { @OnRecord( topics={"my-topic"} ) public void onMsg(ConsumerRecord record) { …
- 33. @OMIHALYI Or evolution to avoid refactoring event observer JCA connection observer MDB event
- 34. @OMIHALYI Evolutionary architecture „An evolutionary architecture supports continual and incremental change as a first principle along multiple dimensions.“ „Microservices meet this definition.“ Neal Ford, Rebecca Parsons http://evolutionaryarchitecture.com/
- 37. @OMIHALYI ● Standard config sources – Env. variables – System properties ● Pluggable sources – Database?, secrets? ● More sources in Payara Micro – Cluster-wide – Directory, secrets – Scoped (server, app, module) Microprofile Configuration @Inject @ConfigProperty(name = "myservice.url") URL myService; URL myService = ConfigProvider.getConfig() .getValue("myservice.url", URL.class);
- 38. @OMIHALYI DEMO
- 40. @OMIHALYI Is there a free lunch? Microprofile provides a lot out of the box ● Metrics – monitoring data, statistics ● Health – problem detection and autorecovery ● Opentracing – connects related requests
- 41. JCache JAX-RS JCA connector Microprofile Configuration Microprofile Metrics, Health, Tracing Microprofile JWT Future? Microprofile FaultTolerance