ApsaraMQ for RocketMQは、拡張アーキテクチャ (X/Open XA) と同様の分散トランザクション処理機能を提供し、ApsaraMQ for RocketMQのトランザクションの一貫性を確保します。 このトピックでは、C# 用HTTPクライアントSDKを使用してトランザクションメッセージを送受信する方法に関するサンプルコードを提供します。
背景情報
の前提条件
開始する前に、次の操作が実行されていることを確認してください。
SDK for C# をインストールします。 詳細については、「環境の準備」をご参照ください。
ApsaraMQ for RocketMQコンソールのコードで指定するリソースを作成します。 リソースには、インスタンス、トピック、および消費者グループが含まれます。 詳細については、「リソースの作成」 をご参照ください。
Alibaba CloudアカウントのAccessKeyペアを取得します。 詳細については、「AccessKey の作成」をご参照ください。
トランザクションメッセージの送信
次のサンプルコードは、C# 用HTTPクライアントSDKを使用してトランザクションメッセージを送信する方法の例を示しています。
using System;
using System.Collections.Generic;
using System.Threading;
using Aliyun.MQ.Model;
using Aliyun.MQ.Model.Exp;
using Aliyun.MQ.Util;
namespace Aliyun.MQ.Sample
{
public class TransProducerSample
{
// The HTTP endpoint. You can obtain the endpoint in the HTTP Endpoint section of the Instance Details page in the ApsaraMQ for RocketMQ console.
private const string _endpoint = "${HTTP_ENDPOINT}";
// Make sure that the environment variables ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET are configured.
// The AccessKey ID that is used for authentication.
private const string _accessKeyId = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_ID");
// The AccessKey secret that is used for authentication.
private const string _secretAccessKey = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_SECRET");
// The topic in which the message is produced. You must create the topic in the ApsaraMQ for RocketMQ console.
private const string _topicName = "${TOPIC}";
// The ID of the instance to which the topic belongs. You must create the instance in the ApsaraMQ for RocketMQ console.
// If the instance has a namespace, specify the ID of the instance. If the instance does not have a namespace, set the instanceID parameter to null or an empty string. You can obtain the namespace of the instance on the Instance Details page in the ApsaraMQ for RocketMQ console.
private const string _instanceId = "${INSTANCE_ID}";
// The ID of the consumer group that you created in the ApsaraMQ for RocketMQ console.
private const string _groupId = "${GROUP_ID}";
private static readonly MQClient _client = new Aliyun.MQ.MQClient(_accessKeyId, _secretAccessKey, _endpoint);
private static readonly MQTransProducer transProducer = _client.GetTransProdcuer(_instanceId, _topicName, _groupId);
static void ProcessAckError(Exception exception)
{
// If the transactional message is committed or rolled back after the time specified by the TransCheckImmunityTime parameter for the handle of the transactional message elapses or after the timeout period specified for the handle of consumeHalfMessage elapses, the commit or rollback fails. In this example, the timeout period is specified as 10 seconds for the handle of consumeHalfMessage.
if (exception is AckMessageException)
{
AckMessageException ackExp = (AckMessageException)exception;
Console.WriteLine("Ack message fail, RequestId:" + ackExp.RequestId);
foreach (AckMessageErrorItem errorItem in ackExp.ErrorItems)
{
Console.WriteLine("\tErrorHandle:" + errorItem.ReceiptHandle + ",ErrorCode:" + errorItem.ErrorCode + ",ErrorMsg:" + errorItem.ErrorMessage);
}
}
}
static void ConsumeHalfMessage()
{
int count = 0;
while (true)
{
if (count == 3)
break;
try
{
// Check for half messages. This is similar to consuming normal messages.
List<Message> messages = null;
try
{
messages = transProducer.ConsumeHalfMessage(3, 3);
} catch (Exception exp1) {
if (exp1 is MessageNotExistException)
{
Console.WriteLine(Thread.CurrentThread.Name + " No half message, " + ((MessageNotExistException)exp1).RequestId);
continue;
}
Console.WriteLine(exp1);
Thread.Sleep(2000);
}
if (messages == null)
continue;
// The message consumption logic.
foreach (Message message in messages)
{
Console.WriteLine(message);
int a = int.Parse(message.GetProperty("a"));
uint consumeTimes = message.ConsumedTimes;
try {
if (a == 1) {
// Confirm to commit the transactional message.
transProducer.Commit(message.ReceiptHandle);
count++;
Console.WriteLine("Id:" + message.Id + ", commit");
} else if (a == 2 && consumeTimes > 1) {
// Confirm to commit the transactional message.
transProducer.Commit(message.ReceiptHandle);
count++;
Console.WriteLine("Id:" + message.Id + ", commit");
} else if (a == 3) {
// Confirm to roll back the transactional message.
transProducer.Rollback(message.ReceiptHandle);
count++;
Console.WriteLine("Id:" + message.Id + ", rollback");
} else {
// Check the status next time.
Console.WriteLine("Id:" + message.Id + ", unkonwn");
}
} catch (Exception ackError) {
ProcessAckError(ackError);
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex);
Thread.Sleep(2000);
}
}
}
static void Main(string[] args)
{
// The client needs a thread or a process to process unacknowledged transactional messages.
// Start a thread to process unacknowledged transactional messages.
Thread consumeHalfThread = new Thread(ConsumeHalfMessage);
consumeHalfThread.Start();
try
{
// Cyclically send four transactional messages. Among the four messages, commit one message after the message is sent, and process the other three messages based on the specified conditions.
for (int i = 0; i < 4; i++)
{
TopicMessage sendMsg = new TopicMessage("trans_msg");
sendMsg.MessageTag = "a";
sendMsg.MessageKey = "MessageKey";
sendMsg.PutProperty("a", i.ToString());
// The time interval between the sending time of the transactional message and the start time of the first check for the status of the local transaction. This time interval specifies the relative time when the status is first checked. Unit: seconds. Valid values: 10 to 300.
// If the message is not committed or rolled back after the first back-check for the status of the local transaction, the broker initiates a back-check request for the status of the local transaction every 10 seconds within 24 hours.
sendMsg.TransCheckImmunityTime = 10;
TopicMessage result = transProducer.PublishMessage(sendMsg);
Console.WriteLine("publis message success:" + result);
try {
if (!string.IsNullOrEmpty(result.ReceiptHandle) && i == 0)
{
// After the producer sends the transactional message, the broker obtains the handle of the half message that corresponds to the transactional message, and can directly commit or roll back the half message.
transProducer.Commit(result.ReceiptHandle);
Console.WriteLine("Id:" + result.Id + ", commit");
}
} catch (Exception ackError) {
ProcessAckError(ackError);
}
}
} catch (Exception ex) {
Console.Write(ex);
}
consumeHalfThread.Join();
}
}
}トランザクションメッセージの購読
次のサンプルコードは、トランザクションメッセージをサブスクライブする方法の例を示しています。
using System;
using System.Collections.Generic;
using System.Threading;
using Aliyun.MQ.Model;
using Aliyun.MQ.Model.Exp;
using Aliyun.MQ;
namespace Aliyun.MQ.Sample
{
public class ConsumerSample
{
// The HTTP endpoint. You can obtain the endpoint in the HTTP Endpoint section of the Instance Details page in the ApsaraMQ for RocketMQ console.
private const string _endpoint = "${HTTP_ENDPOINT}";
// Make sure that the environment variables ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET are configured.
// The AccessKey ID that is used for authentication.
private const string _accessKeyId = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_ID");
// The AccessKey secret that is used for authentication.
private const string _secretAccessKey = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_SECRET");
// The topic in which the message is produced. You must create the topic in the ApsaraMQ for RocketMQ console.
private const string _topicName = "${TOPIC}";
// The ID of the instance to which the topic belongs. You must create the instance in the ApsaraMQ for RocketMQ console.
// If the instance has a namespace, specify the ID of the instance. If the instance does not have a namespace, set the instanceID parameter to null or an empty string. You can obtain the namespace of the instance on the Instance Details page in the ApsaraMQ for RocketMQ console.
private const string _instanceId = "${INSTANCE_ID}";
// The ID of the consumer group that you created in the ApsaraMQ for RocketMQ console.
private const string _groupId = "${GROUP_ID}";
private static MQClient _client = new Aliyun.MQ.MQClient(_accessKeyId, _secretAccessKey, _endpoint);
static MQConsumer consumer = _client.GetConsumer(_instanceId, _topicName, _groupId, null);
static void Main(string[] args)
{
// Cyclically consume messages in the current thread. We recommend that you use multiple threads to concurrently consume messages.
while (true)
{
try
{
// Consume messages in long polling mode.
// In long polling mode, if no message in the topic is available for consumption, the request is suspended on the broker for the specified period of time. If a message is available for consumption within the specified period of time, a response is immediately sent to the consumer. In this example, the value is specified as 3 seconds.
List<Message> messages = null;
try
{
messages = consumer.ConsumeMessage(
3, // The maximum number of messages that can be consumed at a time. In this example, the value is specified as 3. The largest value you can specify is 16.
3 // The duration of a long polling period. Unit: seconds. In this example, the value is specified as 3. The maximum value that you can specify is 30.
);
}
catch (Exception exp1)
{
if (exp1 is MessageNotExistException)
{
Console.WriteLine(Thread.CurrentThread.Name + " No new message, " + ((MessageNotExistException)exp1).RequestId);
continue;
}
Console.WriteLine(exp1);
Thread.Sleep(2000);
}
if (messages == null)
{
continue;
}
List<string> handlers = new List<string>();
Console.WriteLine(Thread.CurrentThread.Name + " Receive Messages:");
// The message consumption logic.
foreach (Message message in messages)
{
Console.WriteLine(message);
Console.WriteLine("Property a is:" + message.GetProperty("a"));
handlers.Add(message.ReceiptHandle);
}
// If the broker fails to receive an acknowledgement (ACK) for a message from the consumer before the period of time specified by the Message.nextConsumeTime parameter elapses, the broker delivers the message for consumption again.
// A unique timestamp is specified for the handle of a message each time the message is consumed.
try
{
consumer.AckMessage(handlers);
Console.WriteLine("Ack message success:");
foreach (string handle in handlers)
{
Console.Write("\t" + handle);
}
Console.WriteLine();
}
catch (Exception exp2)
{
// If the handle of the message times out, the broker fails to receive an ACK for the message from the consumer.
if (exp2 is AckMessageException)
{
AckMessageException ackExp = (AckMessageException)exp2;
Console.WriteLine("Ack message fail, RequestId:" + ackExp.RequestId);
foreach (AckMessageErrorItem errorItem in ackExp.ErrorItems)
{
Console.WriteLine("\tErrorHandle:" + errorItem.ReceiptHandle + ",ErrorCode:" + errorItem.ErrorCode + ",ErrorMsg:" + errorItem.ErrorMessage);
}
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex);
Thread.Sleep(2000);
}
}
}
}
}