org.apache.druid.server.coordination

Class ChangeRequestHttpSyncer<T>

java.lang.Object

org.apache.druid.server.coordination.ChangeRequestHttpSyncer<T>

public class ChangeRequestHttpSyncer<T>
extends Object

This class facilitates the usage of long-polling HTTP endpoints powered by ChangeRequestHistory. For example HttpServerInventoryView uses it to keep segment state in sync with data nodes which expose the segment state via HTTP endpoint in SegmentListerResource.getSegments(long, long, long, javax.servlet.http.HttpServletRequest).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ChangeRequestHttpSyncer.Listener<T> Concurrency guarantees: all calls to ChangeRequestHttpSyncer.Listener.fullSync(java.util.List<T>) and ChangeRequestHttpSyncer.Listener.deltaSync(java.util.List<T>) (that is done within the executor) are linearizable.

Field Summary

Fields

Modifier and Type	Field and Description
static long	HTTP_TIMEOUT_EXTRA_MS

Constructor Summary

Constructors

Constructor and Description
ChangeRequestHttpSyncer(com.fasterxml.jackson.databind.ObjectMapper smileMapper, HttpClient httpClient, ScheduledExecutorService executor, URL baseServerURL, String baseRequestPath, com.fasterxml.jackson.core.type.TypeReference<ChangeRequestsSnapshot<T>> responseTypeReferences, long serverTimeoutMS, long serverUnstabilityTimeout, ChangeRequestHttpSyncer.Listener<T> listener)

Method Summary

Modifier and Type	Method and Description
boolean	awaitInitialization(long timeout, TimeUnit timeUnit) Wait for first fetch of segment listing from server.
Map<String,Object>	getDebugInfo() This method returns the debugging information for printing, must not be used for any other purpose.
long	getServerHttpTimeout()
boolean	isOK() Exposed for monitoring use to see if sync is working fine and not stopped due to any coding bugs.
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Field Detail

HTTP_TIMEOUT_EXTRA_MS

public static final long HTTP_TIMEOUT_EXTRA_MS

See Also:

Constant Field Values

Constructor Detail

ChangeRequestHttpSyncer

public ChangeRequestHttpSyncer(com.fasterxml.jackson.databind.ObjectMapper smileMapper,
                               HttpClient httpClient,
                               ScheduledExecutorService executor,
                               URL baseServerURL,
                               String baseRequestPath,
                               com.fasterxml.jackson.core.type.TypeReference<ChangeRequestsSnapshot<T>> responseTypeReferences,
                               long serverTimeoutMS,
                               long serverUnstabilityTimeout,
                               ChangeRequestHttpSyncer.Listener<T> listener)

Method Detail

start

public void start()

stop

public void stop()

awaitInitialization

public boolean awaitInitialization(long timeout,
                                   TimeUnit timeUnit)
                            throws InterruptedException

Wait for first fetch of segment listing from server.

Throws:

InterruptedException

getDebugInfo

public Map<String,Object> getDebugInfo()

This method returns the debugging information for printing, must not be used for any other purpose.

isOK

public boolean isOK()

Exposed for monitoring use to see if sync is working fine and not stopped due to any coding bugs. If this ever returns false then caller of this method must create an alert and it should be looked into for any bugs.

getServerHttpTimeout

public long getServerHttpTimeout()