/**
* Return a service instance POJO
*
* @param name name of the service
* @param id ID of the instance
* @return the instance or <code>null</code> if not found
* @throws Exception errors
*/
@Override
public ServiceInstance<T> queryForInstance(String name, String id) throws Exception {
String path = pathForInstance(name, id);
try {
byte[] bytes = client.getData().forPath(path);
return serializer.deserialize(bytes);
} catch (KeeperException.NoNodeException ignore) {
// ignore
}
return null;
}
@Override
public void updateService(final ServiceInstance<T> service) throws Exception {
Entry<T> entry = services.get(service.getId());
if (entry == null) {
throw new Exception("Service not registered: " + service);
}
synchronized (entry) {
entry.service = service;
byte[] bytes = serializer.serialize(service);
String path = pathForInstance(service.getName(), service.getId());
client.setData().forPath(path, bytes);
}
}
@VisibleForTesting
protected void internalRegisterService(ServiceInstance<T> service) throws Exception {
byte[] bytes = serializer.serialize(service);
String path = pathForInstance(service.getName(), service.getId());
final int MAX_TRIES = 2;
boolean isDone = false;
for (int i = 0; !isDone && (i < MAX_TRIES); ++i) {
try {
CreateMode mode =
(service.getServiceType() == ServiceType.DYNAMIC)
? CreateMode.EPHEMERAL
: CreateMode.PERSISTENT;
client.create().creatingParentsIfNeeded().withMode(mode).forPath(path, bytes);
isDone = true;
} catch (KeeperException.NodeExistsException e) {
client.delete().forPath(path); // must delete then re-create so that watchers fire
}
}
}
