ApsaraMQ for RocketMQ:Send and receive transactional messages

A figura a seguir ilustra o processo de interação das mensagens transacionais.

Para mais detalhes, consulte Mensagens transacionais.

//#include <iostream>
#include <fstream>
#ifdef _WIN32
#include <windows.h>
#include <process.h>
#else
#include "pthread.h"
#endif
#include "mq_http_sdk/mq_client.h"

using namespace std;
using namespace mq::http::sdk;

const int32_t pubMsgCount = 4;
const int32_t halfCheckCount = 3;

void processCommitRollError(AckMessageResponse& bdmResp, const std::string& messageId) {
    if (bdmResp.isSuccess()) {
        cout << "Commit/Roll Transaction Suc: " << messageId << endl;
        return;
    }
    const std::vector<AckMessageFailedItem>& failedItems =
        bdmResp.getAckMessageFailedItem();
    for (std::vector<AckMessageFailedItem>::const_iterator iter = failedItems.begin();
            iter != failedItems.end(); ++iter)
    {
        cout << "Commit/Roll Transaction ERROR: " << iter->errorCode
            << "  " << iter->receiptHandle << endl;
    }
}

#ifdef WIN32
unsigned __stdcall consumeHalfMessageThread(void *arg)
#else
void* consumeHalfMessageThread(void *arg)
#endif
{
    MQTransProducerPtr transProducer = *(MQTransProducerPtr*)(arg);
    int count = 0;
    do {
        std::vector<Message> halfMsgs;
        try {
            // Long polling: if no half message is available, the request hangs
            // on the broker for the specified duration before returning.
            transProducer->consumeHalfMessage(
                    1, // Max messages per request (max: 16)
                    3, // Long polling timeout in seconds (max: 30)
                    halfMsgs
                    );
        } catch (MQServerException& me) {
            if (me.GetErrorCode() == "MessageNotExist") {
                cout << "No half message to consume! RequestId: " + me.GetRequestId() << endl;
                continue;
            }
            cout << "Request Failed: " + me.GetErrorCode() + ".RequestId: " + me.GetRequestId() << endl;
        }
        if (halfMsgs.size() == 0) {
            continue;
        }

        cout << "Consume Half: " << halfMsgs.size() << " Messages!" << endl;
        // Process each half message and decide: commit, rollback, or defer.
        std::vector<std::string> receiptHandles;
        for (std::vector<Message>::iterator iter = halfMsgs.begin();
                iter != halfMsgs.end(); ++iter)
        {
            cout << "MessageId: " << iter->getMessageId()
                << " PublishTime: " << iter->getPublishTime()
                << " Tag: " << iter->getMessageTag()
                << " Body: " << iter->getMessageBody()
                << " FirstConsumeTime: " << iter->getFirstConsumeTime()
                << " NextConsumeTime: " << iter->getNextConsumeTime()
                << " ConsumedTimes: " << iter->getConsumedTimes()
                << " Properties: " << iter->getPropertiesAsString()
                << " Key: " << iter->getMessageKey() << endl;

            int32_t consumedTimes = iter->getConsumedTimes();
            const std::string propA = iter->getProperty("a");
            const std::string handle = iter->getReceiptHandle();
            AckMessageResponse bdmResp;
            if (propA == "1") {
                cout << "Commit msg.." << endl;
                transProducer->commit(handle, bdmResp);
                count++;
            } else if(propA == "2") {
                if (consumedTimes > 1) {
                    cout << "Commit msg.." << endl;
                    transProducer->commit(handle, bdmResp);
                    count++;
                } else {
                    cout << "Commit Later!!!" << endl;
                }
            } else if(propA == "3") {
                cout << "Rollback msg.." << endl;
                transProducer->rollback(handle, bdmResp);
                count++;
            } else {
                transProducer->commit(handle, bdmResp);
                cout << "Unkown msg.." << endl;
            }
            // Commit or rollback must complete before NextConsumeTime.
            // Otherwise, the operation fails.
            processCommitRollError(bdmResp, iter->getMessageId());
        }

    } while(count < halfCheckCount);

#ifdef WIN32
    return 0;
#else
    return NULL;
#endif
}

int main() {

    MQClient mqClient(
            // HTTP endpoint. Find this in the HTTP Endpoint section
            // of the Instance Details page in the ApsaraMQ for RocketMQ console.
            "${HTTP_ENDPOINT}",
            // Obtain AccessKey credentials from environment variables.
            // ALIBABA_CLOUD_ACCESS_KEY_ID: AccessKey ID for authentication
	          System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"),
            // ALIBABA_CLOUD_ACCESS_KEY_SECRET: AccessKey secret for authentication
	          System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET")
            );

    // Topic for publishing messages.
    // Create this topic in the ApsaraMQ for RocketMQ console.
    string topic = "${TOPIC}";
    // Instance ID. If the instance has no namespace, set this to an empty string.
    // Check the Instance Details page for namespace information.
    string instanceId = "${INSTANCE_ID}";
    // Consumer group ID. Create this in the ApsaraMQ for RocketMQ console.
    string groupId = "${GROUP_ID}";

    MQTransProducerPtr transProducer;
    if (instanceId == "") {
        transProducer = mqClient.getTransProducerRef(topic, groupId);
    } else {
        transProducer = mqClient.getTransProducerRef(instanceId, topic, groupId);
    }

    // Start a background thread to handle transaction status checks
    // (consume and resolve unacknowledged half messages).
#ifdef WIN32
    HANDLE thread;
    unsigned int threadId;
    thread = (HANDLE)_beginthreadex(NULL, 0, consumeHalfMessageThread, &transProducer, 0, &threadId);
#else
    pthread_t thread;
    pthread_create(&thread, NULL, consumeHalfMessageThread, static_cast<void *>(&transProducer));
#endif

    try {
        for (int i = 0; i < pubMsgCount; i++)
        {
            PublishMessageResponse pmResp;
            TopicMessage pubMsg("Hello, mq, trans_msg!");
            pubMsg.putProperty("a",std::to_string(i));
            pubMsg.setMessageKey("ImKey");
            pubMsg.setTransCheckImmunityTime(10);
            transProducer->publishMessage(pubMsg, pmResp);
            cout << "Publish mq message success. Topic:" << topic
                << ", msgId:" << pmResp.getMessageId()
                << ", bodyMD5:" << pmResp.getMessageBodyMD5()
                << ", Handle:" << pmResp.getReceiptHandle() << endl;

            if (i == 0) {
                // Immediately commit the first message using its receipt handle.
                // Commit or rollback must complete before TransCheckImmunityTime
                // elapses; otherwise, the operation fails.
                AckMessageResponse bdmResp;
                transProducer->commit(pmResp.getReceiptHandle(), bdmResp);
                processCommitRollError(bdmResp, pmResp.getMessageId());
            }
        }
    } catch (MQServerException& me) {
        cout << "Request Failed: " + me.GetErrorCode() << ", requestId is:" << me.GetRequestId() << endl;
    } catch (MQExceptionBase& mb) {
        cout << "Request Failed: " + mb.ToString() << endl;
    }

#ifdef WIN32
    WaitForSingleObject(thread, INFINITE);
    CloseHandle(thread);
#else
    pthread_join(thread, NULL);
#endif

    return 0;
}

Lógica de verificação de transação

A thread em segundo plano resolve cada half-message com base na propriedade personalizada a:

#include <vector>
#include <fstream>
#include "mq_http_sdk/mq_client.h"

#ifdef _WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif

using namespace std;
using namespace mq::http::sdk;

int main() {

    MQClient mqClient(
            // The HTTP endpoint, found in the HTTP Endpoint section
            // of the Instance Details page in the ApsaraMQ for RocketMQ console.
            "${HTTP_ENDPOINT}",
            // The AccessKey ID and AccessKey secret for authentication.
            // Read from environment variables to avoid hardcoding credentials.
            System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"),
            System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET")
            );

    // The topic to consume messages from. Create the topic in the ApsaraMQ for RocketMQ console.
    string topic = "${TOPIC}";
    // The consumer group ID. Create the consumer group in the ApsaraMQ for RocketMQ console.
    string groupId = "${GROUP_ID}";
    // The instance ID. If the instance has no namespace, set this to an empty string.
    // Check the namespace on the Instance Details page in the console.
    string instanceId = "${INSTANCE_ID}";

    MQConsumerPtr consumer;
    if (instanceId == "") {
        consumer = mqClient.getConsumerRef(topic, groupId);
    } else {
        consumer = mqClient.getConsumerRef(instanceId, topic, groupId, "");
    }

    do {
        try {
            std::vector<Message> messages;
            // Consume messages in long polling mode.
            // If no messages are available, the broker holds the request for the specified
            // polling duration and responds immediately when a message arrives.
            consumer->consumeMessage(
                    3, // Batch size: max messages per request. Maximum allowed: 16.
                    3, // Polling duration in seconds. Maximum allowed: 30.
                    messages
            );
            cout << "Consume: " << messages.size() << " Messages!" << endl;

            // Process each message and collect receipt handles for acknowledgment.
            std::vector<std::string> receiptHandles;
            for (std::vector<Message>::iterator iter = messages.begin();
                    iter != messages.end(); ++iter)
            {
                cout << "MessageId: " << iter->getMessageId()
                    << " PublishTime: " << iter->getPublishTime()
                    << " Tag: " << iter->getMessageTag()
                    << " Body: " << iter->getMessageBody()
                    << " FirstConsumeTime: " << iter->getFirstConsumeTime()
                    << " NextConsumeTime: " << iter->getNextConsumeTime()
                    << " ConsumedTimes: " << iter->getConsumedTimes()
                    << " Properties: " << iter->getPropertiesAsString()
                    << " Key: " << iter->getMessageKey() << endl;
                receiptHandles.push_back(iter->getReceiptHandle());
            }

            // Send an ACK to the broker. If the broker does not receive an ACK before
            // NextConsumeTime, it redelivers the message. Each receipt handle carries
            // a unique timestamp that expires after the NextConsumeTime window.
            AckMessageResponse bdmResp;
            consumer->ackMessage(receiptHandles, bdmResp);
            if (!bdmResp.isSuccess()) {
                // Log failed ACK items. A handle that has expired causes ACK failure,
                // and the broker redelivers the corresponding message.
                const std::vector<AckMessageFailedItem>& failedItems =
                    bdmResp.getAckMessageFailedItem();
                for (std::vector<AckMessageFailedItem>::const_iterator iter = failedItems.begin();
                        iter != failedItems.end(); ++iter)
                {
                    cout << "AckFailedItem: " << iter->errorCode
                        << "  " << iter->receiptHandle << endl;
                }
            } else {
                cout << "Ack: " << messages.size() << " messages suc!" << endl;
            }
        } catch (MQServerException& me) {
            if (me.GetErrorCode() == "MessageNotExist") {
                cout << "No message to consume! RequestId: " + me.GetRequestId() << endl;
                continue;
            }
            cout << "Request Failed: " + me.GetErrorCode() + ".RequestId: " + me.GetRequestId() << endl;
#ifdef _WIN32
            Sleep(2000);
#else
            usleep(2000 * 1000);
#endif
        } catch (MQExceptionBase& mb) {
            cout << "Request Failed: " + mb.ToString() << endl;
#ifdef _WIN32
            Sleep(2000);
#else
            usleep(2000 * 1000);
#endif
        }

    } while(true);
}