atris commented on a change in pull request #1686: URL: https://github.com/apache/lucene-solr/pull/1686#discussion_r460687788
########## File path: solr/core/src/java/org/apache/solr/servlet/RateLimitManager.java ########## @@ -0,0 +1,153 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.solr.servlet; + +import javax.servlet.FilterConfig; +import javax.servlet.http.HttpServletRequest; +import java.util.HashMap; +import java.util.Map; + +import org.apache.solr.client.solrj.SolrRequest; + +import static org.apache.solr.common.params.CommonParams.SOLR_REQUEST_CONTEXT_PARAM; +import static org.apache.solr.common.params.CommonParams.SOLR_REQUEST_TYPE_PARAM; + +/** + * This class is responsible for managing rate limiting per request type. Rate limiters + * can be registered with this class against a corresponding type. There can be only one + * rate limiter associated with a request type. + * + * The actual rate limiting and the limits should be implemented in the corresponding RequestRateLimiter + * implementation. RateLimitManager is responsible for the orchestration but not the specifics of how the + * rate limiting is being done for a specific request type. + */ +public class RateLimitManager { + public final static int DEFAULT_CONCURRENT_REQUESTS= 10; + public final static long DEFAULT_EXPIRATION_TIME_INMS = 300; + public final static long DEFAULT_SLOT_ACQUISITION_TIMEOUT_MS = -1; + + private final Map<String, RequestRateLimiter> requestRateLimiterMap; + + public RateLimitManager() { + this.requestRateLimiterMap = new HashMap<String, RequestRateLimiter>(); + } + + // Handles an incoming request. The main orchestration code path, this method will + // identify which (if any) rate limiter can handle this request. Internal requests will not be + // rate limited + // Returns true if request is accepted for processing, false if it should be rejected + + // NOTE: It is upto specific rate limiter implementation to handle queuing of rejected requests. + public boolean handleRequest(HttpServletRequest request) throws InterruptedException { + String requestContext = request.getHeader(SOLR_REQUEST_CONTEXT_PARAM); + String typeOfRequest = request.getHeader(SOLR_REQUEST_TYPE_PARAM); + + if (typeOfRequest == null) { + // Cannot determine if this request should be throttled + return true; + } + + // Do not throttle internal requests + if (requestContext != null && requestContext.equals(SolrRequest.SolrClientContext.SERVER.toString())) { + return true; + } + + RequestRateLimiter requestRateLimiter = requestRateLimiterMap.get(typeOfRequest); + + if (requestRateLimiter == null) { + // No request rate limiter for this request type + return true; + } + + return requestRateLimiter.handleRequest(request); + } + + // Resume a pending request from one of the registered rate limiters. + // The current model is round robin -- iterate over the list and get a pending request and resume it. + + // TODO: This should be a priority queue based model + public void resumePendingRequest(HttpServletRequest request) { + String typeOfRequest = request.getHeader(SOLR_REQUEST_TYPE_PARAM); + + RequestRateLimiter previousRequestRateLimiter = requestRateLimiterMap.get(typeOfRequest); + + if (previousRequestRateLimiter == null) { + // No rate limiter for this request type + return; + } + + // Give preference to the previous request's rate limiter + if (previousRequestRateLimiter.resumePendingOperation()) { + return; + } + + for (Map.Entry<String, RequestRateLimiter> currentEntry : requestRateLimiterMap.entrySet()) { Review comment: This is work stealing -- a thread first tries to get work from its own request rate limiter and if not present, let the thread be used for a different request type. This is to allow smoothening out of skews. Added a flag to enable or disable this behaviour. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
