philipnee commented on a change in pull request #11797: URL: https://github.com/apache/kafka/pull/11797#discussion_r819086900
########## File path: connect/runtime/src/main/java/org/apache/kafka/connect/util/RetryUtil.java ########## @@ -0,0 +1,105 @@ +/* + * 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.kafka.connect.util; + +import org.apache.kafka.common.errors.RetriableException; +import org.apache.kafka.common.errors.WakeupException; +import org.apache.kafka.common.utils.Utils; +import org.apache.kafka.connect.errors.ConnectException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.time.Duration; +import java.util.Optional; +import java.util.concurrent.Callable; +import java.util.function.Supplier; + +public class RetryUtil { + private static final Logger log = LoggerFactory.getLogger(RetryUtil.class); + + /** + * The method executes the callable at least once, optionally retrying the callable if + * {@link org.apache.kafka.connect.errors.RetriableException} is being thrown. If timeout is exhausted, + * then the last exception is wrapped with a {@link org.apache.kafka.connect.errors.ConnectException} and thrown. + * + * <p>{@code description} supplies the message that indicates the purpose of the callable since the message will + * be used for logging. For example, "list offsets". If the supplier is null or the supplied string is + * null, {@call callable} will be used as the default string. + * + * <p>If {@code timeoutDuration} is set to 0, the task will be + * executed exactly once. If {@code timeoutDuration} is less than {@code retryBackoffMs}, the callable will be + * executed only once. + * + * <p>If {@code retryBackoffMs} is set to 0, no wait will happen in between the retries. + * + * @param callable the function to execute. + * @param description supplier that provides custom message for logging purpose + * @param timeoutDuration timeout duration; may not be null + * @param retryBackoffMs the number of milliseconds to delay upon receiving a + * {@link org.apache.kafka.connect.errors.RetriableException} before retrying again; + * must be 0 or more + * @throws ConnectException If the task exhausted all the retries. + */ + public static <T> T retryUntilTimeout(Callable<T> callable, Supplier<String> description, Duration timeoutDuration, long retryBackoffMs) throws Exception { + if (timeoutDuration == null) { + throw new IllegalArgumentException("timeoutDuration cannot be null"); + } + + // if null supplier or string is provided, the message will be default to "callabe" + String descriptionStr = Optional.ofNullable(description) + .map(Supplier::get) + .orElse("callable"); + + long timeoutMs = timeoutDuration.toMillis(); + + if (retryBackoffMs >= timeoutMs) { + log.warn("Call to {} will only execute once, since retryBackoffMs={} is larger than total timeoutMs={}", + descriptionStr, retryBackoffMs, timeoutMs); + } + + if (retryBackoffMs >= timeoutMs || + timeoutMs <= 0) { + // no retry + return callable.call(); + } + + long end = System.currentTimeMillis() + timeoutMs; + int attempt = 0; + Throwable lastError = null; + while (System.currentTimeMillis() <= end) { + attempt++; + try { + return callable.call(); + } catch (RetriableException | org.apache.kafka.connect.errors.RetriableException e) { + log.warn("Attempt {} to execute {} resulted in RetriableException; retrying automatically. " + + "Reason: {}", attempt, descriptionStr, e.getMessage(), e); + lastError = e; + } catch (WakeupException e) { + lastError = e; + } + + // if current time is less than the ending time, no more retry is necessary + // won't sleep if retryBackoffMs equals to 0 + long millisRemaining = Math.max(0, end - System.currentTimeMillis()); + if (millisRemaining > 0) { + Utils.sleep(retryBackoffMs); + } + } + + throw new ConnectException("Fail to execute " + descriptionStr + " after " + attempt + " attempts. Reason: " + lastError.getMessage(), lastError); Review comment: A comment on the logging message, I think they can be grammatically strange if the provided description isn't a verb. E.g., "Fail to logging error". Probably not a big deal. -- 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. 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