| /** |
| * 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. |
| */ |
| |
| #ifndef PULSAR_CPP_CONSUMER_INTERCEPTOR_H |
| #define PULSAR_CPP_CONSUMER_INTERCEPTOR_H |
| |
| #include <pulsar/Message.h> |
| #include <pulsar/Result.h> |
| #include <pulsar/defines.h> |
| |
| #include <set> |
| |
| namespace pulsar { |
| |
| class Consumer; |
| |
| /** |
| * A plugin interface that allows you to intercept (and possibly mutate) |
| * messages received by the consumer. |
| * |
| * <p>A primary use case is to hook into consumer applications for custom |
| * monitoring, logging, etc. |
| * |
| * <p>Exceptions thrown by interceptor methods will be caught, logged, but |
| * not propagated further. |
| */ |
| class PULSAR_PUBLIC ConsumerInterceptor { |
| public: |
| virtual ~ConsumerInterceptor() {} |
| /** |
| * Close the interceptor |
| */ |
| virtual void close() {} |
| |
| /** |
| * This is called just before the message is consumed. |
| * |
| * <p>This method is allowed to modify message, in which case the new message |
| * will be returned. |
| * |
| * <p>Any exception thrown by this method will be caught by the caller, logged, |
| * but not propagated to client. |
| * |
| * <p>Since the consumer may run multiple interceptors, a particular |
| * interceptor's <tt>beforeConsume</tt> callback will be called in the order. |
| * The first interceptor in the list gets the consumed message, the following interceptor will be passed |
| * the message returned by the previous interceptor, and so on. Since |
| * interceptors are allowed to modify message, interceptors may potentially |
| * get the messages already modified by other interceptors. However building a |
| * pipeline of mutable interceptors that depend on the output of the previous interceptor is |
| * discouraged, because of potential side-effects caused by interceptors |
| * potentially failing to modify the message and throwing an exception. |
| * if one of interceptors in the list throws an exception from |
| * <tt>beforeConsume</tt>, the exception is caught, logged, |
| * and the next interceptor is called with the message returned by the last |
| * successful interceptor in the list, or otherwise the original consumed |
| * message. |
| * |
| * @param consumer the consumer which contains the interceptor |
| * @param message the message to be consumed by the client |
| * @return message that is either modified by the interceptor or same message |
| * passed into the method. |
| */ |
| virtual Message beforeConsume(const Consumer& consumer, const Message& message) = 0; |
| |
| /** |
| * |
| * This is called before consumer sends the acknowledgment to the broker. |
| * |
| * <p>Any exception thrown by this method will be ignored by the caller. |
| * |
| * @param consumer the consumer which contains the interceptor |
| * @param result the result of the acknowledgement |
| * @param messageID the message id to be acknowledged |
| */ |
| virtual void onAcknowledge(const Consumer& consumer, Result result, const MessageId& messageID) = 0; |
| |
| /** |
| * |
| * This is called before consumer sends the cumulative acknowledgment to the broker. |
| * |
| * <p>Any exception thrown by this method will be ignored by the caller. |
| * |
| * @param consumer the consumer which contains the interceptor |
| * @param result the result of the cumulative acknowledgement |
| * @param messageID the message id to be acknowledged cumulatively |
| */ |
| virtual void onAcknowledgeCumulative(const Consumer& consumer, Result result, |
| const MessageId& messageID) = 0; |
| |
| /** |
| * This method will be called when a redelivery from a negative acknowledge occurs. |
| * |
| * <p>Any exception thrown by this method will be ignored by the caller. |
| * |
| * @param consumer the consumer which contains the interceptor |
| * @param messageIds the set of message ids to negative ack |
| */ |
| virtual void onNegativeAcksSend(const Consumer& consumer, const std::set<MessageId>& messageIds) = 0; |
| }; |
| |
| typedef std::shared_ptr<ConsumerInterceptor> ConsumerInterceptorPtr; |
| } // namespace pulsar |
| |
| #endif // PULSAR_CPP_CONSUMER_INTERCEPTOR_H |