Jean-Louis Monteiro gave a presentation on MicroProfile and microservices. He discussed what MicroProfile is, which includes specifications for CDI, JAX-RS and JSON-P. He demonstrated a simple MicroProfile application and how to deploy applications to Raspberry Pi devices using Docker. He also overviewed various MicroProfile specifications like configuration, metrics, health checks and fault tolerance.

1. Lightweight Enterprise
Java with MicroProfile
Jean-Louis Monteiro
@JLouisMonteiro
tomitribe.com

2. Who am I?
• Tomitribe Director of Engineering
• Long time Apache contributor, committer and PMC
• JCP expert group member and now Jakarta EE
• Involved in MicroProfile
• Speaker when possible
#tomee@JLouisMonteiro

3. Why am I here today?
• What are microservices?
• What is MicroProfile?
• Raspberry PI Demos
• MicroProfile future and Jakarta EE
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4. Microservices?
How big is a microservice?
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5. What other think?
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6. My favorite one?
“If you can’t build monolith
correctly, why do you think
putting network in the middle
will help?” by @simonbrown
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7. Why microservices?
A technical perspective
• Avoid big monolith architecture
• Reusable parts
• No big bang deployment
• Scale services independently
• Self contained systems
• Cloud friendly
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8. Why microservices?
An organizational perspective
• Deliver new feature quicker
• Smaller, agile teams and parallel development
• Organizational changes free (Conway’s law)
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9. New challenges for microservices?
• Scalability
• Cost reduction
• Resilience
• Monitoring
• Security
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10. What is MicroProfile?
• https://microprofile.io/
• Enterprise Java for Microservices
• Open Source
• Hosted at Eclipse Foundation
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11. What is MicroProfile?
• Initial version 1.0 with CDI, JAX-RS, JSON-P
• Application portability across runtimes
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12. What is MicroProfile?
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13. What is MicroProfile?
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14. MicroProfile implementations?
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15. • CDI
• JAX-RS
• JSON-P
My first MicroProfile app
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16. CDI
• Contexts and Dependency Injection
• Bean Lifecycle and Typesafe Injection
• Producers
• Interceptors
• Observers
#tomee@JLouisMonteiro

17. JAX-RS
• RESTful Web Services
• Annotation based
• HTTP Centric
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18. JSON-P
• Parse, Generate Transform and Query JSON
• Streaming API
• Object Model API
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19. @ApplicationScoped
@Path("books")
public class BookResource {
@Inject
private BookBean bookBean;
@GET
@Path("{id}")
public Response find(@PathParam("id") final Long id) {
final Book book = bookBean.find(id);
final JsonObjectBuilder builder = Json.createObjectBuilder();
builder.add("id", book.getId())
.add("name", book.getTitle());
return Response.ok(builder.build().toString()).build();
}
}
Putting it all together
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20. Show me the code!
https://github.com/jeanouii/microprofile-samples
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21. Architecture diagram
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Router
number-api
book-api

22. Deploy
• Raspberry PI running Hypriot OS.
• Package everything with Docker
• Local Docker Registry
• Push Docker Images with Ansible
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23. Deployment diagram
#tomee@JLouisMonteiro
Router
Microservices
docker-repo

24. Raspberry PI
• Raspberry V3
• HypriotOS is a minimal Debian dist
• Optimized to run Docker on a Raspberry PI
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25. Docker
• Use Maven Fabric8 Plugin
• Docker Hub too slow
• Use a Local Docker Registry
• Speed up Deployment
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26. Ansible
• Automate Tasks
• Ping PIs
• Deploy Docker Images, Start, Stop
• Ansible Playbooks
• List of tasks to perform
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27. Show me the code!
Evolving your MicroProfile application
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28. Configuration
• Applications need configuration based on their running
environment
• It must be possible to change configuration without repacking
the application
• Based on DeltaSpike Config, Apache Tamaya and Sabot
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29. Configuration
• META-INF/microprofile-config.properties
• Environment properties
• System properties
• Pluggable to allow custom config sources and providers
through the ServiceLoader mechanism
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30. public class MoviesRest {
@Inject
@ConfigProperty(name="connection.url")
private String setting;
@Inject
@ConfigProperty(name="connection.port")
private Optional<Integer> port;
public void execute() {
Config config = ConfigProvider.getConfig();
String url = config.getValue("connection.url", String.class);
}
}
Configuration
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31. Metrics
• Monitor essential System Parameters
• Ensure reliable operation of software
• Monitoring endpoints to collect data
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32. Metrics
• Accessible via REST interface
• /metrics/base for MP compliant servers
• /metrics/application for Application specific Metrics
• /metrics/vendor for Server specific metrics
• OPTIONS provides metadata, such as Unit of measure
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33. GET /metrics/base
{
"thread.count" : 33,
"thread.max.count" : 47,
"memory.maxHeap" : 3817863211,
"memory.usedHeap" : 16859081,
"memory.committedHeap" : 64703546
}
Metrics
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34. OPTIONS /metrics/base
{
"fooVal": {
"unit": "milliseconds",
"type": "gauge",
"description": "The average duration of foo requests during last 5
minutes",
"displayName": "Duration of foo",
"tags": "app=webshop"
},
"barVal": {
"unit": "megabytes",
"type": "gauge",
"tags": "component=backend,app=webshop"
}
}
Metrics
#tomee@JLouisMonteiro

35. Healthchecks
• Probe the state of a computer node
• Primary target cloud infrastructure
• Automated processes to maintain the state of nodes
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36. Healthchecks
• Simple API to specify health status
• /health JAX-RS endpoint reporting server health
• Response status indicates if the health check passed
• Payload can include more detail
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37. @Health
@ApplicationScoped
public class CheckDiskSpace implements HealthCheck {
public HealthCheckResponse call() {
}
}
Healthchecks
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38. GET /health
{
"outcome": "UP",
"checks": [{
"name": "diskspace",
"state": "UP",
"data": {
"key": "freebytes",
"freebytes": "126000000000"
}
}]
}
Healthchecks
#tomee@JLouisMonteiro

39. Fault tolerance
• Different strategies to guide the execution and result of some
logic
• TimeOut, RetryPolicy, Fallback, Bulkhead and Circuit Breaker
• Inspired by Hystrix and Failsafe
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40. @CircuitBreaker
@Fallback(NumberFallbackHandler.class)
public String getNumber() {
final Response response = numberApi.request().get();
if (OK.getStatusCode() == response.getStatus()) {
return response.readEntity(String.class);
}
throw new WebApplicationException(INTERNAL_SERVER_ERROR);
}
public class NumberFallbackHandler implements FallbackHandler<String> {
@Override
public String handle(final ExecutionContext context) {
return "FALLBACK_NUMBER";
}
}
Fault tolerance
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41. JWT Propagation
• Security Tokens
• Most common: OAuth2, OpenID Connect JWT
• Lightweight way to propagate identities across different
services
• https://github.com/tomitribe/microservice-with-jwt-and-
microprofile
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42. Open Tracing
• Trace the flow of a request across services
• OpenTracing is a distributed tracing standard for applications
• Java Binding to OpenTracing Implementation
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43. @Trace
@GET
@Path(“/findByStatus")
public Response findPetsByStatus() { }
@Inject
private Tracer tracer;
tracer.activeSpan().setTag(…);
tracer.activeSpan().log(...);
tracer.activeSpan().setBaggage(...);
Open Tracing
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44. OpenAPI
• Java API for the OpenAPI v3 specification
• OpenAPI v3 is based on Swagger v2
• Annotations should be similar
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45. @GET
@Path(“/findByStatus")
@Operation(
summary = "Finds Pets by status",
description = "Multiple status values can be provided with comma separated strings")
public Response findPetsByStatus() { }
GET /openapi
/pet/findByStatus:
get:
summary: Finds Pets by status
description: Multiple status values can be provided with comma separated strings
operationId: findPetsByStatus
OpenAPI
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46. REST Client
• Microservices typically talk REST to other services
• Several JAX-RS implementations already support interface
definition
• Consistent and easy to reuse
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47. REST Client
• Type safe REST Service over HTTP
• Extends JAX-RS 2.0 API’s
• More natural code style
• Similar to Feign
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48. @RegisterRestClient
public interface MyServiceClient {
@GET
@Path("/greet")
Response greet();
}
@ApplicationScoped
public class MyService {
@Inject
@RestClient
private MyServiceClient client;
}
REST Client
#tomee@JLouisMonteiro

49. Future 2.2 and above
• Long Running Actions
• Reactive Streams
• Reactive Events
• Data Access
• Event Data
• Service meshes
• Concurrency
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50. Get Involved
https://groups.google.com/forum/#!forum/microprofile
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51. Resources
• http://microprofile.io/
• http://tomee.apache.org
• https://github.com/jeanouii/microprofile-samples
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52. Thank you!
#tomee@JLouisMonteiro