microservice come in systems
TRANSCRIPT
ONE MICROSERVICEIS NO MICROSERVICETHEY COME IN SYSTEMS
@Path("/orders/")@Interceptors(CallAudit.class)@Stateless public class OrderService {
@EJB BillingService billing; @EJB DeliveryService delivery; @EJB Warehouse warehouse;
@PUT @Produces({"application/xml","application/json"}) @Consumes({"application/xml","application/json"}) public Order order(Order newOrder){ Order order = warehouse.checkout(newOrder); billing.payForOrder(order); delivery.deliver(order); return order; }
@GET @Path("{orderid}/") @Produces({"application/xml","application/json"}) public Order status(@PathParam("orderid") long orderId){ return delivery.status(orderId); }}
@Path("/orders/")@Interceptors(CallAudit.class)@Stateless public class OrderService {
private Client client; private WebTarget tut;
// ...
@GET @Path("{orderid}/") @Produces({"application/xml","application/json"}) public Order status(@PathParam("orderid") long orderId){ // return delivery.status(orderId); this.client = ClientBuilder.newClient(); this.tut = this.client.target("http://..."); Order order = this.client.target(location).request(MediaType.APPLICATION_XML).get(Order.class); return order; }}
COMPLEX DEPLOYMENT
LARGE TEAMS
BREAKING UP MONOLITHS ADDS COMPLEXITY
BUILDING ONE MICROSERVICE IS GENERALLY EASY.
WHAT IS HARD IS BUILDING A SYSTEM OF MICROSERVICES.
REST - MONOLITH TO MICROSERVICES
REST tends to be our go-to but…> Don’t just do a 1:1 service/interface replacement
> Instead… Design for an asynchronous architecture
Pro-tip: Watch Ben Christensen’s “Don’t build a distributed Monolith” talk from Microservices Practitioner Summit
2016
HOW SHOULD WE BUILD
MICROSERVICE SYSTEMS?
Traditional application architectures
and platforms are obsolete.— Gartner
Architectureand software design principles
matter even more today.— Eisele
ARCHITECTURE PRINCIPLES
> Single Responsible Principle> Service Oriented Architecture
> Encapsulation> Separation of Concern
> Loose Coupling> Hexagonal Architecture
SOFTWARE DESIGN PATTERNS
> Domain-driven Design> Bounded Contexts
> Event Sourcing> CQRS
> Eventual Consistency> Context Maps
We need to build systems for flexibility and resiliency, not just efficiency and robustness.
> Responsive
> Resilient
> Elastic
> Message driven
SCALA, AKKA AND PLAY ARE GREAT FITS HERE
Have a steep learning curveStill a lot to build out yourself
Not explicitly build for microservices
BUT LAGOM IS HERE TO HELP
> Developer experience first!> No ad-hoc scripts to run your
services> Takes you through to production
deployment
WHAT IS IN LAGOM?
> sbt build tool> Scala 2.11 and JDK8
> Play 2.5> Akka 2.4
> Cassandra> Jackson
> Google Guice
HIGHLY OPPINIONATED
> Service API> Persistence API
> Development environment> Production environment
LAGOM SERVICE API
> IO and communication> Streaming between services as a first-class concept
> Higher level of resilience and scalability with no blocking
> Service is a Bounded Context in DDD> Service Clients & Endpoints
LAGOM PERSISTENCE API
> Event sourced (deltas) with Cassandra backend by default
> No object/relational impedance mismatch> Can always replay to determine current state> Allows you to learn more from your data later> Persistent entity is an Aggregate Root in DDD
> Can be overridden for CRUD if you want
DEVELOPMENT ENVIRONMENT$ cd my-first-system$ activator... (booting up)> runAll[info] Starting embedded Cassandra server..........[info] Cassandra server running at 127.0.0.1:4000[info] Service locator is running at http://localhost:8000[info] Service gateway is running at http://localhost:9000[info] Service helloworld-impl listening for HTTP on 0:0:0:0:0:0:0:0:24266[info] Service hellostream-impl listening for HTTP on 0:0:0:0:0:0:0:0:26230(Services started, use Ctrl+D to stop and go back to the console...)
NEXT STEPS FOR LAGOM
> Scala API> Swagger integration
> Maven support> Support for more DBs
> Integration with other cluster orchestration tools
> … What is missing?
CONTRIBUTE TO LAGOM
Lagom on GitHubLagom Mailinglist
@LagomChat Room
REACTIVE MICROSERVICES ARCHITECTURE
BIT.LY/REACTIVEMICROSERVICE
> explore a microservice architecture> based on Reactive principles
> for building an isolated service that’s
> scalable, resilient to failure,> and combines with other services
> to form a cohesive whole
DEVELOPING REACTIVE MICROSERVICES
HTTP://BIT.LY/DEVELOPREACTIVEMICROSERVICE
> create base services, expose endpoints, and then connect them
with a simple, web-based user interface
> deal with persistence, state, and clients
> Use integration technologies to start a successful migration away
from legacy systems
NEXT STEPS
Project Site:http://www.lightbend.com/lagom
GitHub Repo:https://github.com/lagom
Documentation:http://www.lagomframework.com/documentation/1.0.x/
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