murblanc commented on a change in pull request #1684: URL: https://github.com/apache/lucene-solr/pull/1684#discussion_r467453739
########## File path: solr/core/src/java/org/apache/solr/cluster/placement/PlacementPlugin.java ########## @@ -0,0 +1,41 @@ +/* + * 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.cluster.placement; + +/** + * Implemented by external plugins to control replica placement and movement on the search cluster (as well as other things + * such as cluster elasticity?) when cluster changes are required (initiated elsewhere, most likely following a Collection + * API call). + */ +public interface PlacementPlugin { Review comment: I believe Solr side would keep the configuration (map) somewhere and just pass a reference to it on every call to the plugin. So cost would be minimal. If the plugin code needs to retrieve a config value, it will basically do a `get` on that map, very low cost here as well. I don't see how a plugin can keep state between invocations with a semantic that's different from a static field, unless we create a notion of higher level context shared between invocations (and different such higher level contexts will not be shared). I suggest we skip that aspect for now and reconsider later when we implement real plugins. For now I believe the model in which the plugin is instantiated (no arg constructor, or constructor getting the config map or something simple like that) before every call to the computePlacement method would be sufficient. ---------------------------------------------------------------- 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
