chungen0126 commented on code in PR #10159: URL: https://github.com/apache/ozone/pull/10159#discussion_r3445566927
########## hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/local/PortAllocator.java: ########## @@ -0,0 +1,72 @@ +/* + * 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.hadoop.ozone.local; + +import java.io.IOException; +import java.net.ServerSocket; +import java.util.HashSet; +import java.util.Set; + +/** + * Allocates unique ports for local Ozone services. + * + * <p>This allocator ensures that each service gets a unique port, + * either by using a preferred port or by finding a free ephemeral port. + * It tracks all reserved ports to prevent conflicts when multiple + * services are started in the same JVM.</p> + */ +final class PortAllocator { + + private final Set<Integer> reserved = new HashSet<>(); + + /** + * Reserves a port for use by a local service. + * + * @param preferredPort the preferred port to use, or 0 to auto-allocate + * @return the reserved port number + * @throws IOException if the preferred port is already reserved or + * if no free port can be found + */ + int reserve(int preferredPort) throws IOException { + if (preferredPort > 0) { + if (!reserved.add(preferredPort)) { + throw new IOException("Port " + preferredPort + + " is configured more than once."); + } + return preferredPort; + } + + while (true) { + int candidate = findFreePort(); + if (reserved.add(candidate)) { + return candidate; + } + } + } + + /** + * Finds a free ephemeral port by opening and immediately closing + * a server socket. + */ + private static int findFreePort() throws IOException { Review Comment: I think the `findFreePort` method could be extracted for use by other ozone-local components. I also reviewed [PR](https://github.com/apache/ozone/pull/10455) from @henrybear327 , and it looks like he’s using similar logic there as well. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
