narendly commented on a change in pull request #744: Add read endpoints of metadata store directory service to helix rest URL: https://github.com/apache/helix/pull/744#discussion_r377462688
########## File path: helix-rest/src/main/java/org/apache/helix/rest/server/resources/zookeeper/MetadataStoreDirectoryAccessor.java ########## @@ -0,0 +1,163 @@ +package org.apache.helix.rest.server.resources.zookeeper; + +/* + * 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. + */ + +import java.util.Collection; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.NoSuchElementException; +import javax.ws.rs.GET; +import javax.ws.rs.Path; +import javax.ws.rs.QueryParam; +import javax.ws.rs.core.Response; + +import com.google.common.collect.ImmutableMap; +import org.apache.helix.rest.common.ContextPropertyKeys; +import org.apache.helix.rest.common.HelixRestNamespace; +import org.apache.helix.rest.common.HelixRestUtils; +import org.apache.helix.rest.metadatastore.MetadataStoreDirectory; +import org.apache.helix.rest.metadatastore.ZkMetadataStoreDirectory; +import org.apache.helix.rest.metadatastore.constant.MetadataStoreDirectoryConstants; +import org.apache.helix.rest.metadatastore.exceptions.InvalidRoutingDataException; +import org.apache.helix.rest.server.resources.AbstractResource; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Provides REST endpoints for accessing metadata store directory service, + * which responds to read/write requests of metadata store realms, sharding keys, etc.. + */ +@Path("") +public class MetadataStoreDirectoryAccessor extends AbstractResource { + private static final Logger LOG = LoggerFactory.getLogger(MetadataStoreDirectoryAccessor.class); + + private HelixRestNamespace _namespace; + private MetadataStoreDirectory _metadataStoreDirectory; + + /** + * Gets all metadata store realms in a namespace with the endpoint. + * + * @return Json representation of all realms. + */ + @GET + @Path("/metadata-store-realms") + public Response getAllMetadataStoreRealms() { + Map<String, Collection<String>> responseMap = new HashMap<>(1); + try { + Collection<String> realms = + getMetadataStoreDirectory().getAllMetadataStoreRealms(getHelixNamespace().getName()); + responseMap.put( + MetadataStoreDirectoryConstants.METADATA_STORE_REALMS_NAME, realms); + } catch (NoSuchElementException ex) { + return notFound(ex.getMessage()); + } + + return JSONRepresentation(responseMap); + } + + /** + * Gets sharding keys mapped at path "HTTP GET /sharding-keys" which returns all sharding keys in + * a namespace, or path "HTTP GET /sharding-keys?realm={realmName}" which returns sharding keys in + * a realm. + * + * @param realm Query param in endpoint path + * @return Json representation of a map: shardingKeys -> collection of sharding keys. + */ + @GET + @Path("/sharding-keys") + public Response getShardingKeys(@QueryParam("realm") String realm) { + Map<String, Object> responseMap; + Collection<String> shardingKeys; + try { + // If realm is not set in query param, the endpoint is: "/sharding-keys" + // to get all sharding keys in a namespace. + if (realm == null) { + shardingKeys = + getMetadataStoreDirectory().getAllShardingKeys(getHelixNamespace().getName()); + // To avoid allocating unnecessary resource, limit the map's capacity only for + // SHARDING_KEYS_NAME. + responseMap = new HashMap<>(1); + } else { + // For endpoint: "/sharding-keys?realm={realmName}" + shardingKeys = getMetadataStoreDirectory() + .getAllShardingKeysInRealm(getHelixNamespace().getName(), realm); + // To avoid allocating unnecessary resource, limit the map's capacity only for + // SHARDING_KEYS_NAME and "metadataStoreRealm". + responseMap = new HashMap<>(2); + responseMap.put("metadataStoreRealm", realm); + } + } catch (NoSuchElementException ex) { + return notFound(ex.getMessage()); + } + + responseMap.put(MetadataStoreDirectoryConstants.SHARDING_KEYS_NAME, shardingKeys); + + return JSONRepresentation(responseMap); + } + + private MetadataStoreDirectory getMetadataStoreDirectory() { + if (_metadataStoreDirectory == null) { + synchronized (this) { + if (_metadataStoreDirectory == null) { + Map<String, String> routingZkAddressMap = ImmutableMap + .of(getHelixNamespace().getName(), getHelixNamespace().getMetadataStoreAddress()); + try { + _metadataStoreDirectory = new ZkMetadataStoreDirectory(routingZkAddressMap); + } catch (InvalidRoutingDataException ex) { + // In this case, the InvalidRoutingDataException should not happen because routing + // ZK address is always valid here. + LOG.warn("Unable to create metadata store directory for routing address: {}", Review comment: routing "ZK" address? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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