Spring Cloud Zookeeper and Service Registry
Spring Cloud Zookeeper implements the ServiceRegistry interface, letting developers
register arbitrary services in a programmatic way.
The ServiceInstanceRegistration class offers a builder() method to create a
Registration object that can be used by the ServiceRegistry, as shown in the following
example:
@Autowired
private ZookeeperServiceRegistry serviceRegistry;
public void registerThings() {
ZookeeperRegistration registration = ServiceInstanceRegistration.builder()
.defaultUriSpec()
.address("anyUrl")
.port(10)
.name("/a/b/c/d/anotherservice")
.build();
this.serviceRegistry.register(registration);
}Instance Status
Netflix Eureka supports having instances that are OUT_OF_SERVICE registered with the server.
These instances are not returned as active service instances.
This is useful for behaviors such as blue/green deployments.
(Note that the Curator Service Discovery recipe does not support this behavior.) Taking advantage of the flexible payload has let Spring Cloud Zookeeper implement OUT_OF_SERVICE by updating some specific metadata and then filtering on that metadata in the Spring Cloud LoadBalancer ZookeeperServiceInstanceListSupplier.
The ZookeeperServiceInstanceListSupplier filters out all non-null instance statuses that do not equal UP.
If the instance status field is empty, it is considered to be UP for backwards compatibility.
To change the status of an instance, make a POST with OUT_OF_SERVICE to the ServiceRegistry
instance status actuator endpoint, as shown in the following example:
$ http POST http://localhost:8081/serviceregistry status=OUT_OF_SERVICE
The preceding example uses the http command from httpie.org.
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