Package org.apache.druid.server.http

Class SegmentListerResource

java.lang.Object

org.apache.druid.server.http.SegmentListerResource

public class SegmentListerResource
extends Object

Endpoints exposed here are to be used only for druid internal management of segments by Coordinators, Brokers etc.

Field Summary

Fields

Modifier and Type	Field	Description
protected final com.fasterxml.jackson.databind.ObjectMapper	jsonMapper
protected static final EmittingLogger	log
protected final com.fasterxml.jackson.databind.ObjectMapper	smileMapper

Constructor Summary

Constructors

Constructor	Description
SegmentListerResource(com.fasterxml.jackson.databind.ObjectMapper jsonMapper, com.fasterxml.jackson.databind.ObjectMapper smileMapper, BatchDataSegmentAnnouncer announcer, SegmentLoadDropHandler loadDropRequestHandler)

Method Summary

Modifier and Type	Method	Description
void	applyDataSegmentChangeRequests(long timeout, SegmentLoadingMode loadingMode, List<DataSegmentChangeRequest> changeRequestList, javax.servlet.http.HttpServletRequest req)	This endpoint is used by HttpLoadQueuePeon to assign segment load/drop requests batch.
javax.ws.rs.core.Response	getSegmentLoadingCapabilities(javax.servlet.http.HttpServletRequest req)
Void	getSegments(long counter, long hash, long timeout, javax.servlet.http.HttpServletRequest req)	This endpoint is used by HttpServerInventoryView to keep an up-to-date list of segments served by historical/realtime nodes.

Methods inherited from class java.lang.Object

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

Field Details

log

protected static final EmittingLogger log

jsonMapper

protected final com.fasterxml.jackson.databind.ObjectMapper jsonMapper

smileMapper

protected final com.fasterxml.jackson.databind.ObjectMapper smileMapper

Constructor Details

SegmentListerResource

@Inject
public SegmentListerResource(com.fasterxml.jackson.databind.ObjectMapper jsonMapper,
 com.fasterxml.jackson.databind.ObjectMapper smileMapper,
 @Nullable
 BatchDataSegmentAnnouncer announcer,
 @Nullable
 SegmentLoadDropHandler loadDropRequestHandler)

Method Details

getSegments

public Void getSegments(long counter,
 long hash,
 long timeout,
 @Context
 javax.servlet.http.HttpServletRequest req)
                 throws IOException

This endpoint is used by HttpServerInventoryView to keep an up-to-date list of segments served by historical/realtime nodes. This endpoint lists segments served by this server and can also incrementally provide the segments added/dropped since last response. Here is how, this is used. (1) Client sends first request /druid/internal/v1/segments?counter=-1&timeout= Server responds with list of segments currently served and a <counter,hash> pair. (2) Client sends subsequent requests /druid/internal/v1/segments?counter=&hash=&timeout= Where <counter,hash> values are used from the last response. Server responds with list of segment updates since given counter. This endpoint makes the client wait till either there is some segment update or given timeout elapses. So, clients keep on sending next request immediately after receiving the response in order to keep the list of segments served by this server up-to-date.

Parameters:

counter - counter received in last response.

hash - hash received in last response.

timeout - after which response is sent even if there are no new segment updates.

req -

Returns:

null to avoid "MUST return a non-void type" warning.

Throws:

IOException

applyDataSegmentChangeRequests

public void applyDataSegmentChangeRequests(long timeout,
 @Nullable
 SegmentLoadingMode loadingMode,
 List<DataSegmentChangeRequest> changeRequestList,
 @Context
 javax.servlet.http.HttpServletRequest req)
                                    throws IOException

This endpoint is used by HttpLoadQueuePeon to assign segment load/drop requests batch. This endpoint makes the client wait till one of the following events occur. Note that this is implemented using async IO so no jetty threads are held while in wait.

1. Given timeout elapses.
2. Some load/drop request completed.

It returns a map of "load/drop request -> SUCCESS/FAILED/PENDING status" for each request in the batch.

Throws:

IOException

getSegmentLoadingCapabilities

public javax.ws.rs.core.Response getSegmentLoadingCapabilities(@Context
 javax.servlet.http.HttpServletRequest req)