atris commented on a change in pull request #1626: URL: https://github.com/apache/lucene-solr/pull/1626#discussion_r447738671
########## File path: solr/core/src/java/org/apache/solr/util/circuitbreaker/CircuitBreakerManager.java ########## @@ -0,0 +1,128 @@ +/* + * 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.util.circuitbreaker; + +import java.util.HashMap; +import java.util.Map; + +import org.apache.solr.core.SolrConfig; + +/** + * Manages all registered circuit breaker instances. Responsible for a holistic view + * of whether a circuit breaker has tripped or not. + * + * There are two typical ways of using this class's instance: + * 1. Check if any circuit breaker has triggered -- and know which circuit breaker has triggered. + * 2. Get an instance of a specific circuit breaker and perform checks. + * + * It is a good practice to register new circuit breakers here if you want them checked for every + * request. + * + * NOTE: The current way of registering new default circuit breakers is minimal and not a long term + * solution. There will be a follow up with a SIP for a schema API design. + */ +public class CircuitBreakerManager { + + private final Map<CircuitBreakerType, CircuitBreaker> circuitBreakerMap = new HashMap<>(); + + // Allows replacing of existing circuit breaker + public void registerCircuitBreaker(CircuitBreakerType circuitBreakerType, CircuitBreaker circuitBreaker) { + circuitBreakerMap.put(circuitBreakerType, circuitBreaker); + } + + public CircuitBreaker getCircuitBreaker(CircuitBreakerType circuitBreakerType) { + assert circuitBreakerType != null; + + return circuitBreakerMap.get(circuitBreakerType); + } + + /** + * Check if any circuit breaker has triggered. + * @return CircuitBreakers which have triggered, null otherwise + */ + public Map<CircuitBreakerType, CircuitBreaker> checkedTrippedCircuitBreakers() { + Map<CircuitBreakerType, CircuitBreaker> triggeredCircuitBreakers = null; + + for (Map.Entry<CircuitBreakerType, CircuitBreaker> entry : circuitBreakerMap.entrySet()) { + CircuitBreaker circuitBreaker = entry.getValue(); + + if (circuitBreaker.isEnabled() && + circuitBreaker.isTripped()) { + if (triggeredCircuitBreakers == null) { + triggeredCircuitBreakers = new HashMap<>(); + } + + triggeredCircuitBreakers.put(entry.getKey(), circuitBreaker); + } + } + + return triggeredCircuitBreakers; + } + + /** + * Returns true if *any* circuit breaker has triggered, false if none have triggered + * + * NOTE: This method short circuits the checking of circuit breakers -- the method will + * return as soon as it finds a circuit breaker that is enabled and has triggered + */ + public boolean checkAnyCircuitBreakerTripped() { + for (Map.Entry<CircuitBreakerType, CircuitBreaker> entry : circuitBreakerMap.entrySet()) { + CircuitBreaker circuitBreaker = entry.getValue(); + + if (circuitBreaker.isEnabled() && + circuitBreaker.isTripped()) { + return true; + } + } + + return false; + } + + /** + * Construct the final error message to be printed when circuit breakers trip + * @param circuitBreakerMap Input list for circuit breakers + * @return Constructed error message + */ + public static String constructFinalErrorMessageString(Map<CircuitBreakerType, CircuitBreaker> circuitBreakerMap) { + assert circuitBreakerMap != null; + + StringBuilder sb = new StringBuilder(); + + for (CircuitBreakerType circuitBreakerType : circuitBreakerMap.keySet()) { + sb.append(circuitBreakerType.toString() + " " + circuitBreakerMap.get(circuitBreakerType).getDebugInfo()); + } + + return sb.toString(); + } + + /** + * Register default circuit breakers and return a constructed CircuitBreakerManager + * instance which serves the given circuit breakers. + * + * Any default circuit breakers should be registered here + */ + public static CircuitBreakerManager buildDefaultCircuitBreakerManager(SolrConfig solrConfig) { Review comment: Fixed, thanks. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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