org.wikidata.query.rdf.blazegraph.throttling

Class Throttler<B>

java.lang.Object

org.wikidata.query.rdf.blazegraph.throttling.Throttler<B>

Type Parameters:

B - type of the bucket used to differentiate clients

public class Throttler<B>
extends Object

Implement throttling logic.

See Also:

for a more complete description of how throttling works.

Constructor Summary

Constructors

Constructor and Description
Throttler(Duration requestTimeThreshold, Bucketing<B> bucketing, Callable<ThrottlingState> createThrottlingState, com.google.common.cache.Cache<B,ThrottlingState> stateStore, String enableThrottlingIfHeader) Constructor.

Method Summary

Modifier and Type	Method and Description
void	failure(javax.servlet.http.HttpServletRequest request, Duration elapsed) Notify this throttler that a request has completed in error.
Duration	getBackoffDelay(javax.servlet.http.HttpServletRequest request) How long should this client wait before his next request.
boolean	isThrottled(javax.servlet.http.HttpServletRequest request) Should this request be throttled.
void	success(javax.servlet.http.HttpServletRequest request, Duration elapsed) Notify this throttler that a request has been completed successfully.

Methods inherited from class java.lang.Object

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

Constructor Detail

Throttler

public Throttler(Duration requestTimeThreshold,
                 Bucketing<B> bucketing,
                 Callable<ThrottlingState> createThrottlingState,
                 com.google.common.cache.Cache<B,ThrottlingState> stateStore,
                 String enableThrottlingIfHeader)

Constructor. Note that a bucket represent our approximation of a single client.

Parameters:

requestTimeThreshold - requests longer than this will trigger tracking resource consumption

bucketing - how to associate a request with a specific bucket

createThrottlingState - how to create the initial throttling state when we start tracking a specific client

stateStore - the cache in which we store the per client state of throttling

enableThrottlingIfHeader - throttling is only enabled if this header is present.

Method Detail

isThrottled

public boolean isThrottled(javax.servlet.http.HttpServletRequest request)

Should this request be throttled.

Parameters:

request - the request to check

Returns:

true if the request should be throttled

success

public void success(javax.servlet.http.HttpServletRequest request,
                    Duration elapsed)

Notify this throttler that a request has been completed successfully.

Parameters:

request - the request

elapsed - how long that request took

failure

public void failure(javax.servlet.http.HttpServletRequest request,
                    Duration elapsed)

Notify this throttler that a request has completed in error.

Parameters:

request - the request

elapsed - how long that request took

getBackoffDelay

public Duration getBackoffDelay(javax.servlet.http.HttpServletRequest request)

How long should this client wait before his next request.

Parameters:

request - the request

Returns:

0 if no throttling, the backoff delay otherwise