org.apache.druid.discovery

Class DruidLeaderClient

java.lang.Object

org.apache.druid.discovery.DruidLeaderClient

public class DruidLeaderClient
extends Object

This class facilitates interaction with Coordinator/Overlord leader nodes. Instance of this class is injected via Guice with annotations @Coordinator or @IndexingService . Usage: Request request = druidLeaderClient.makeRequest(HttpMethod, requestPath) request.setXXX(..) FullResponseHolder responseHolder = druidLeaderClient.go(request)

Constructor Summary

Constructors

Constructor and Description
DruidLeaderClient(HttpClient httpClient, DruidNodeDiscoveryProvider druidNodeDiscoveryProvider, NodeRole nodeRoleToWatch, String leaderRequestPath, DiscoverySelector<Server> serverDiscoverySelector)

Method Summary

Modifier and Type	Method and Description
String	findCurrentLeader()
StringFullResponseHolder	go(Request request)
<T,H extends FullResponseHolder<T>> H	go(Request request, HttpResponseHandler<H,H> responseHandler) Executes a Request object aimed at the leader.
<Intermediate,Final> com.google.common.util.concurrent.ListenableFuture<Final>	goAsync(Request request, HttpResponseHandler<Intermediate,Final> handler) Executes the request object aimed at the leader and process the response with given handler Note: this method doesn't do retrying on errors or handle leader changes occurred during communication
Request	makeRequest(org.jboss.netty.handler.codec.http.HttpMethod httpMethod, String urlPath) Make a Request object aimed at the leader.
Request	makeRequest(org.jboss.netty.handler.codec.http.HttpMethod httpMethod, String urlPath, boolean cached) Make a Request object aimed at the leader.
void	start()
void	stop()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DruidLeaderClient

public DruidLeaderClient(HttpClient httpClient,
                         DruidNodeDiscoveryProvider druidNodeDiscoveryProvider,
                         NodeRole nodeRoleToWatch,
                         String leaderRequestPath,
                         DiscoverySelector<Server> serverDiscoverySelector)

Method Detail

start

public void start()

stop

public void stop()

makeRequest

public Request makeRequest(org.jboss.netty.handler.codec.http.HttpMethod httpMethod,
                           String urlPath,
                           boolean cached)
                    throws IOException

Make a Request object aimed at the leader. Throws IOException if the leader cannot be located.

Parameters:

cached - Uses cached leader if true, else uses the current leader

Throws:

IOException

makeRequest

public Request makeRequest(org.jboss.netty.handler.codec.http.HttpMethod httpMethod,
                           String urlPath)
                    throws IOException

Make a Request object aimed at the leader. Throws IOException if the leader cannot be located.

Throws:

IOException

go

public StringFullResponseHolder go(Request request)
                            throws IOException,
                                   InterruptedException

Throws:

IOException

InterruptedException

goAsync

public <Intermediate,Final> com.google.common.util.concurrent.ListenableFuture<Final> goAsync(Request request,
                                                                                              HttpResponseHandler<Intermediate,Final> handler)

Executes the request object aimed at the leader and process the response with given handler Note: this method doesn't do retrying on errors or handle leader changes occurred during communication

go

public <T,H extends FullResponseHolder<T>> H go(Request request,
                                                HttpResponseHandler<H,H> responseHandler)
                                         throws IOException,
                                                InterruptedException

Executes a Request object aimed at the leader. Throws IOException if the leader cannot be located.

Throws:

IOException

InterruptedException

findCurrentLeader

public String findCurrentLeader()