Given Quarkus being a framework to develop quick start applications running not just in the Hotspot JVM but also in GraalVM natively, with a relative new lifespan, there are some shortage of integrations with some other services working for the cloud.
With this extension the aim is registering a Quarkus service in Eureka Registry to expose its responsibility to other services in a high availability environment in which the service is reached by loadbalancers to any of their instances.
From the client side point of view, the plugin connects to the Eureka Server to retrieve the bridge which brings the link to the actual application to consume their services. That connections are made through their application id or application name rather a static ip.
The implementation of this extension is built based in the documentation at:
The dependencies that this extension uses are just quarkus extensions and some other dependencies for testing.
The most recent quarkus version at the time, from which this extension has been built, is 2.4.1.Final.
The java version used to implement such plugin is java 11.
To use the plugin, other quarkus extensions need to be provided quarkus-rest-client and quarkus-resteasy-jackson
which are used to communicate with the other end where is the registry.
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-rest-client</artifactId>
</dependency>
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-resteasy-jackson</artifactId>
</dependency>Including the extension in your application, the next dependency needs to be added to your pom.xml:
<dependency>
<groupId>com.github.fmcejudo</groupId>
<artifactId>quarkus-eureka</artifactId>
<version>0.0.14</version>
</dependency>An alternative way to do this is through maven quarkus tool as:
mvn quarkus:add-extension -Dextension="com.github.fmcejudo:quarkus-eureka:0.0.14"
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Configuring connection with the registry, exposing the name of your service, requires adding the next properties to
your quarkus application.properties:
quarkus.eureka.enable=<boolean to tell the application wether to register or not in Eureka. Default to true>
quarkus.eureka.port= <your application port, it should match with quarkus.http.port. If it does not exist,it takes quarkus.http.port>
quarkus.eureka.hostname= <your application address. By default the host where the application has started up>
quarkus.eureka.context-path= <your application context path, using the default one ${quarkus.http.root-path:/}>
quarkus.eureka.prefer-ip-address= <whether or not to override hostname with the application LAN IP address. By default this is set to false>
quarkus.eureka.name= <name of your application in Eureka. It takes quarkus.application.name if it does not exist>
quarkus.eureka.vip-address= <how your application is recognised by clients>
quarkus.eureka.home-page-url= <home path of your application>
quarkus.eureka.status-page-url= <where we can check your status>
quarkus.eureka.health-check-url= <saying if you application is alive and kicking. { "status": "up" }>
quarkus.eureka.region=default
quarkus.eureka.prefer-same-zone=true
quarkus.eureka.service-url.default=<urls of your Eureka instances. ie: http://localhost:8761/eureka>
quarkus.eureka.metadata.<tag-key>=<tag value> #These keys values will be shown in Eureka registry if available i.e.: jhipster-registry
quarkus.eureka.health-check-initial-delay= <delay in seconds before initially checking health before registration. Default 3>i.e: Given a sample application, your configuration properties to work with quarkus-eureka looks like:
# Configuration file
# key = value
quarkus.http.port=8001
quarkus.application.name=sample
quarkus.eureka.region=default
## configuration related to reaching the eureka servers
quarkus.eureka.prefer-same-zone=true
quarkus.eureka.should-use-dns=false
quarkus.eureka.service-url.default=http://localhost:8761/eureka
quarkus.eureka.metadata.app-key=my-quarkus-appHaving as default values for remaining properties the following:
quarkus.eureka.host-name=<host address>
quarkus.eureka.prefer-ip-address=false
quarkus.eureka.port=${quarkus.http.port}
quarkus.eureka.name=${quarkus.application.name}
quarkus.eureka.context-path=${quarkus.http.root-path:/}
quarkus.eureka.home-page-url=/
quarkus.eureka.status-page-url=/info/status
quarkus.eureka.health-check-url=/info/healthIn case you don’t want to implement the heartbeat of your application, you might make use of:
Other alternative is creating your own controller to attend them, a simple approach for this might be:
@Path("/info")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public class HealthCheckController {
@GET
@Path("/health")
public Response health() {
return Response.ok(Map.of("STATUS", "UP")).build();
}
@GET
@Path("/status")
public Response status() {
return Response.ok(Map.of()).build();
}
}applying the endpoints where match.
Eureka registry seems to be ready to work in cloud platforms such as AWS and the API so recognise it. But in this first approach it just connects with Eureka instances in by whole urls.
With this configuration, once you start up you application, it should register itself in the list of locations provided, checking the healthy of its own in the network and the state of the Eureka service where it is registered. It keeps checking at the moment every 40 seconds the availability of them, updating the state if feasible.
Bare in mind that Eureka Server is a service which instances need to teach, Eureka Server itself does not ask to instances about their states.
As client to consume the services posted in Eureka Server, there is a EurekaClient class which requests
for services in Eureka Server, bringing one of the UP status available and presenting the WebTarget configured with
the actual url to the service to link with.
A mechanism has been implemented to select one instance amongst the available ones for the given service, this can be done as:
@Inject
@LoadBalanced(type = LoadBalancerType.ROUND_ROBIN)
public EurekaClient eurekaClient;Being the available ones ROUND_ROBIN or RANDOM.
This WebTarget instance comes from RestEasy implementation which is Quarkus compatible.
To request for an endpoint in sample application, results in:
return eurekaClient.app("sample")
.path("/actuator/health")
.request(MediaType.APPLICATION_JSON_TYPE)
.get()
.readEntity(String.class);In the use case in which your Eureka Server is secure with basic authentication, the way to proceed in your
application.properties file is adding the credential as:
quarkus.eureka.service-url.default=http://user:pass@eureka-server/eurekaThe credentials are added to the request headers in the Authorization field with the value encoded as Basic <base64 value>
The reason to create the extension have been to have other way to make Quarkus openness to use within other services and the way to keep fit learning other new technologies which spread around the business.
This is nothing, but a way to connect Quarkus to the world easily with the guides provided and hopefully one of the multiple integrations with the services we use as developers to monitoring, tracing and scaling our application, letting be more reliable for the future of our work.