dschneider-pivotal commented on a change in pull request #7408: URL: https://github.com/apache/geode/pull/7408#discussion_r828304833
########## File path: geode-for-redis/src/main/java/org/apache/geode/redis/internal/eventing/BlockingCommandListener.java ########## @@ -0,0 +1,121 @@ +/* + * 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.geode.redis.internal.eventing; + +import java.util.Collections; +import java.util.List; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; + +import org.apache.geode.annotations.VisibleForTesting; +import org.apache.geode.redis.internal.commands.Command; +import org.apache.geode.redis.internal.commands.RedisCommandType; +import org.apache.geode.redis.internal.commands.executor.RedisResponse; +import org.apache.geode.redis.internal.data.RedisKey; +import org.apache.geode.redis.internal.netty.Coder; +import org.apache.geode.redis.internal.netty.ExecutionHandlerContext; + +public class BlockingCommandListener implements EventListener { + + private final ExecutionHandlerContext context; + private final Command command; + private final List<RedisKey> keys; + private final double timeoutSeconds; + private final long timeSubmitted; + private final AtomicBoolean active = new AtomicBoolean(true); + + /** + * Constructor to create an instance of a BlockingCommandListener in response to a blocking + * command. When receiving a relevant event, blocking commands simply resubmit the command + * into the Netty pipeline. + * + * @param context the associated ExecutionHandlerContext + * @param command the blocking command associated with this listener + * @param keys the list of keys the command is interested in + * @param timeoutSeconds the timeout for the command to block in seconds + */ + public BlockingCommandListener(ExecutionHandlerContext context, Command command, + List<RedisKey> keys, double timeoutSeconds) { + this.context = context; + this.command = command; + this.timeoutSeconds = timeoutSeconds; + this.keys = Collections.unmodifiableList(keys); + timeSubmitted = System.nanoTime(); + } + + @Override + public List<RedisKey> keys() { + return keys; + } + + @Override + public EventResponse process(RedisCommandType commandType, RedisKey key) { + if (!keys.contains(key)) { + return EventResponse.CONTINUE; + } + + if (active.compareAndSet(true, false)) { + resubmitCommand(); + } + return EventResponse.REMOVE_AND_STOP; + } + + @Override + public void resubmitCommand() { + // Recalculate the timeout since we've already been waiting + double adjustedTimeoutSeconds = 0; + if (timeoutSeconds > 0.0D) { + long timeoutNanos = (long) (timeoutSeconds * 1e9); + long adjustedTimeoutNanos = timeoutNanos - (System.nanoTime() - timeSubmitted); + adjustedTimeoutNanos = Math.max(1, adjustedTimeoutNanos); + adjustedTimeoutSeconds = ((double) adjustedTimeoutNanos) / 1e9; + } + + // The commands we are currently supporting all have the timeout at the end of the argument + // list. Some newer Redis 7 commands (BLMPOP and BZMPOP) have the timeout as the first argument + // after the command. We'll need to adjust this once those commands are supported. + List<byte[]> commandArguments = command.getCommandArguments(); + commandArguments.set(commandArguments.size() - 1, Coder.doubleToBytes(adjustedTimeoutSeconds)); + + context.resubmitCommand(command); + } + + @Override + public void scheduleTimeout(ScheduledExecutorService executor, EventDistributor distributor) { + if (timeoutSeconds == 0) { Review comment: is it worth also returning early if active is false? -- 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: notifications-unsubscr...@geode.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org