reswqa commented on code in PR #29: URL: https://github.com/apache/flink-connector-pulsar/pull/29#discussion_r1108081850
########## flink-connector-pulsar/src/main/java/org/apache/flink/connector/pulsar/common/handler/PulsarAdminInvocationHandler.java: ########## @@ -0,0 +1,152 @@ +/* + * 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.flink.connector.pulsar.common.handler; + +import org.apache.flink.connector.pulsar.common.config.PulsarConfiguration; + +import org.apache.flink.shaded.guava30.com.google.common.util.concurrent.RateLimiter; + +import org.apache.pulsar.client.admin.PulsarAdmin; +import org.apache.pulsar.client.admin.PulsarAdminException; +import org.apache.pulsar.client.admin.PulsarAdminException.NotFoundException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; +import java.util.Map; +import java.util.Optional; +import java.util.concurrent.ConcurrentHashMap; + +import static java.util.concurrent.TimeUnit.MILLISECONDS; +import static org.apache.flink.connector.pulsar.common.config.PulsarOptions.PULSAR_ADMIN_REQUEST_RATES; +import static org.apache.flink.connector.pulsar.common.config.PulsarOptions.PULSAR_ADMIN_REQUEST_RETRIES; +import static org.apache.flink.connector.pulsar.common.config.PulsarOptions.PULSAR_ADMIN_REQUEST_WAIT_MILLIS; +import static org.apache.flink.shaded.guava30.com.google.common.util.concurrent.Uninterruptibles.sleepUninterruptibly; +import static org.apache.flink.util.ExceptionUtils.findThrowable; + +/** A wrapper which wraps the {@link PulsarAdmin} with request retry and rate limit support. */ +public class PulsarAdminInvocationHandler implements InvocationHandler { + private static final Logger LOG = LoggerFactory.getLogger(PulsarAdminInvocationHandler.class); + + @SuppressWarnings("java:S3077") + private static volatile RateLimiter rateLimiter; + + private final PulsarAdmin admin; + private final int retryTimes; + private final long waitMillis; + private final int requestRates; + private final Map<String, Object> handlers; + + public PulsarAdminInvocationHandler(PulsarAdmin admin, PulsarConfiguration configuration) { + this.admin = admin; + this.retryTimes = configuration.get(PULSAR_ADMIN_REQUEST_RETRIES); + this.waitMillis = configuration.get(PULSAR_ADMIN_REQUEST_WAIT_MILLIS); + this.requestRates = configuration.get(PULSAR_ADMIN_REQUEST_RATES); + this.handlers = new ConcurrentHashMap<>(); + } + + @Override + public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { + Class<?> returnType = method.getReturnType(); + + // No need to proxy the void return type. + // The non-interface type is not able to proxy. + if (returnType.equals(Void.TYPE) || !returnType.isInterface()) { + return method.invoke(admin, args); + } + + String methodName = method.getName(); + if (handlers.containsKey(methodName)) { + return handlers.get(methodName); + } + + Object handler = + Proxy.newProxyInstance( + Thread.currentThread().getContextClassLoader(), + new Class[] {returnType}, + new RequestHandler(method.invoke(admin, args))); + this.handlers.put(methodName, handler); + + return handler; + } + + /** A proxy handler with retry support for all the admin request. */ + @SuppressWarnings({"java:S1193", "java:S1181", "java:S3776", "java:S112"}) + private class RequestHandler implements InvocationHandler { + + private final Object handler; + + public RequestHandler(Object handler) { + this.handler = handler; + } + + @Override + public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { + return doInvoke(method, args, retryTimes); + } + + private Object doInvoke(Method method, Object[] args, int remainingTimes) throws Throwable { + while (true) { + // Make sure the request is allowed in the given rates. + requestRateLimit(requestRates); + + try { + return method.invoke(handler, args); + } catch (InvocationTargetException e) { + Optional<PulsarAdminException> optional = + findThrowable(e, PulsarAdminException.class); + if (optional.isPresent()) { + PulsarAdminException ex = optional.get(); + if (ex instanceof NotFoundException) { + // No need to retry on such exceptions. + throw ex; + } + + remainingTimes--; + LOG.warn("Request error in Admin API, remain times: {}", remainingTimes, e); + if (remainingTimes == 0) { + throw ex; + } else { + // Sleep for the given times before executing the next query. + sleepUninterruptibly(waitMillis, MILLISECONDS); + } + } else { + throw e.getCause(); + } + } + } + } + } + + /** Request a global ratelimit which limits the total admin API request rates. */ + private static void requestRateLimit(int requestRates) { + if (rateLimiter == null) { Review Comment: Think about it and find non-lazy singleton is not very suitable for this scene, keep this implementation is good. -- This is an automated message from the Apache Git Service. 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