---

title: “Service Heartbeat” lang: en ref: service-heartbeat permalink: /docs/users/service-heartbeat/ excerpt: “Service Heartbeat” last_modified_at: 2017-08-15T15:01:43-04:00 redirect_from:

• /theme-setup/

---

{% include toc %}

Scenario

After a microservice instance is registered in the service center, the microservice need to periodically send heartbeats to the service center. If the service center receives no heartbeat within a specific period, the instance will be un-registered.

Involved APIs

• org.apache.servicecomb.serviceregistry.client.ServiceRegistryClient is the service client.

ServiceRegistryClient provides heartbeat to send heartbeats. You can call it as required. The sample code is as follows:

public static void main(String[] args) throws Exception {
  // Register the microservice and the instance first
  // Send the heartbeats. Otherwise, the instances will be lost.
  while (true) {
    System.out.println("heartbeat sended:" + client.heartbeat(service2.getServiceId(), instance.getInstanceId()));
    Thread.sleep(3000);
  }
}