murblanc commented on a change in pull request #2148: URL: https://github.com/apache/lucene-solr/pull/2148#discussion_r546277024
########## File path: solr/solrj/src/java/org/apache/solr/common/cloud/PerReplicaStates.java ########## @@ -0,0 +1,587 @@ +/* + * 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.common.cloud; + +import java.io.IOException; +import java.lang.invoke.MethodHandles; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashSet; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Set; +import java.util.function.BiConsumer; + +import org.apache.solr.cluster.api.SimpleMap; +import org.apache.solr.common.MapWriter; +import org.apache.solr.common.SolrException; +import org.apache.solr.common.annotation.JsonProperty; +import org.apache.solr.common.util.ReflectMapWriter; +import org.apache.solr.common.util.StrUtils; +import org.apache.solr.common.util.WrappedSimpleMap; +import org.apache.zookeeper.CreateMode; +import org.apache.zookeeper.KeeperException; +import org.apache.zookeeper.data.ACL; +import org.apache.zookeeper.data.Stat; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static java.util.Collections.singletonList; +import static org.apache.solr.common.params.CommonParams.NAME; +import static org.apache.solr.common.params.CommonParams.VERSION; + +/** + * This represents the individual replica states in a collection + * This is an immutable object. When states are modified, a new instance is constructed + */ +public class PerReplicaStates implements ReflectMapWriter { + private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); + public static final char SEPARATOR = ':'; + + + @JsonProperty + public final String path; + + @JsonProperty + public final int cversion; + + @JsonProperty + public final SimpleMap<State> states; + + public PerReplicaStates(String path, int cversion, List<String> states) { + this.path = path; + this.cversion = cversion; + Map<String, State> tmp = new LinkedHashMap<>(); + + for (String state : states) { + State rs = State.parse(state); + if (rs == null) continue; + State existing = tmp.get(rs.replica); + if (existing == null) { + tmp.put(rs.replica, rs); + } else { + tmp.put(rs.replica, rs.insert(existing)); + } + } + this.states = new WrappedSimpleMap<>(tmp); + + } + + /**Get the changed replicas + */ + public static Set<String> findModifiedReplicas(PerReplicaStates old, PerReplicaStates fresh) { + Set<String> result = new HashSet<>(); + if (fresh == null) { + old.states.forEachKey(result::add); + return result; + } + old.states.forEachEntry((s, state) -> { + // the state is modified or missing + if (!Objects.equals(fresh.get(s) , state)) result.add(s); + }); + fresh.states.forEachEntry((s, state) -> { if (old.get(s) == null ) result.add(s); + }); + return result; + } + + /** + * This is a persist operation with retry if a write fails due to stale state + */ + public static void persist(WriteOps ops, String znode, SolrZkClient zkClient) throws KeeperException, InterruptedException { + try { + persist(ops.get(), znode, zkClient); + } catch (KeeperException.NodeExistsException | KeeperException.NoNodeException e) { + //state is stale + log.info("stale state for {} . retrying...", znode); + List<Op> freshOps = ops.get(PerReplicaStates.fetch(znode, zkClient, null)); + persist(freshOps, znode, zkClient); + log.info("retried for stale state {}, succeeded", znode); + } + } + + /** + * Persist a set of operations to Zookeeper + */ + public static void persist(List<Op> operations, String znode, SolrZkClient zkClient) throws KeeperException, InterruptedException { + if (operations == null || operations.isEmpty()) return; + log.debug("Per-replica state being persisted for :{}, ops: {}", znode, operations); + + List<org.apache.zookeeper.Op> ops = new ArrayList<>(operations.size()); + for (Op op : operations) { + //the state of the replica is being updated + String path = znode + "/" + op.state.asString; + List<ACL> acls = zkClient.getZkACLProvider().getACLsToAdd(path); + ops.add(op.typ == Op.Type.ADD ? + org.apache.zookeeper.Op.create(path, null, acls, CreateMode.PERSISTENT) : + org.apache.zookeeper.Op.delete(path, -1)); + } + try { + zkClient.multi(ops, true); + if (log.isDebugEnabled()) { + //nocommit + try { + Stat stat = zkClient.exists(znode, null, true); + log.debug("After update, cversion : {}", stat.getCversion()); + } catch (Exception e) { + } + + } + } catch (KeeperException e) { + log.error("multi op exception : " + e.getMessage() + zkClient.getChildren(znode, null, true)); + throw e; + } + + } + + + /** + * Fetch the latest {@link PerReplicaStates} . It fetches data after checking the {@link Stat#getCversion()} of state.json. + * If this is not modified, the same object is returned + */ + public static PerReplicaStates fetch(String path, SolrZkClient zkClient, PerReplicaStates current) { + try { + if (current != null) { + Stat stat = zkClient.exists(current.path, null, true); + if (stat == null) return new PerReplicaStates(path, -1, Collections.emptyList()); + if (current.cversion == stat.getCversion()) return current;// not modifiedZkStateReaderTest + } + Stat stat = new Stat(); + List<String> children = zkClient.getChildren(path, null, stat, true); + return new PerReplicaStates(path, stat.getCversion(), Collections.unmodifiableList(children)); + } catch (KeeperException e) { + throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Error fetching per-replica states", e); + } catch (InterruptedException e) { + SolrZkClient.checkInterrupted(e); + throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Thread interrupted when loading per-replica states from " + path, e); + } + } + + + private static List<Op> addDeleteStaleNodes(List<Op> ops, State rs) { + while (rs != null) { + ops.add(new Op(Op.Type.DELETE, rs)); + rs = rs.duplicate; + } + return ops; + } + + public static String getReplicaName(String s) { + int idx = s.indexOf(SEPARATOR); + if (idx > 0) { + return s.substring(0, idx); + } + return null; + } + + public State get(String replica) { + return states.get(replica); + } + + public static class Op { Review comment: `Op` class name is confusion because it is used in places where `org.apache.zookeeper.Op` is also used. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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