FIFO 主题的代码示例 - Amazon Simple Notification Service
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FIFO 主题的代码示例

您可以使用以下代码示例,将汽车零部件价格管理示例使用案例(使用 Amazon SNS FIFO 主题)与 Amazon SQS FIFO 队列或标准队列集成。

使用 Amazon 软件开发工具包

使用 Amazon 开发工具包,您可以通过将 Amazon SNS FIFO 主题的 FifoTopic 属性设置为 true 来创建该主题。您可以通过将 Amazon SQS FIFO 队列的 FifoQueue 属性设置为 true 来创建该队列。此外,您必须将 .fifo 后缀添加到每个 FIFO 资源的名称。创建 FIFO 主题或队列后,无法将其转换为标准主题或队列。

以下代码示例创建这些 FIFO 和标准队列资源:

  • 分发价格更新的 Amazon SNS FIFO 主题

  • 为批发和零售应用程序提供这些更新的 Amazon SQS FIFO 队列

  • 用于存储记录的分析应用程序的 Amazon SQS 标准队列,可以查询这些记录以获取商业智能 (BI)

  • 将三个队列连接到主题的 Amazon SNS FIFO 订阅

本示例将设置订阅中的筛选条件策略。如果通过向主题发布消息来测试示例,请确保您发布的是带 business 属性的消息。为属性值指定 retailwholesale。否则,消息将被筛选掉,且不会传递到订阅的队列中。有关更多信息,请参阅FIFO 主题的消息筛选

Java
适用于 Java 2.x 的 SDK
注意

在 GitHub 上查看更多内容。在 Amazon 代码示例存储库 中查找完整示例,了解如何进行设置和运行。

此示例

  • 创建一个 Amazon SNS FIFO 主题、两个 Amazon SQS FIFO 队列和一个标准队列。

  • 将队列订阅到主题,发布一条消息到主题。

测试验证每个队列是否收到消息。完整的示例还显示了添加访问策略,并在最后删除了资源。

public class PriceUpdateExample { public final static SnsClient snsClient = SnsClient.create(); public final static SqsClient sqsClient = SqsClient.create(); public static void main(String[] args) { final String usage = "\n" + "Usage: " + " <topicName> <wholesaleQueueFifoName> <retailQueueFifoName> <analyticsQueueName>\n\n" + "Where:\n" + " fifoTopicName - The name of the FIFO topic that you want to create. \n\n" + " wholesaleQueueARN - The name of a SQS FIFO queue that will be created for the wholesale consumer. \n\n" + " retailQueueARN - The name of a SQS FIFO queue that will created for the retail consumer. \n\n" + " analyticsQueueARN - The name of a SQS standard queue that will be created for the analytics consumer. \n\n"; if (args.length != 4) { System.out.println(usage); System.exit(1); } final String fifoTopicName = args[0]; final String wholeSaleQueueName = args[1]; final String retailQueueName = args[2]; final String analyticsQueueName = args[3]; // For convenience, the QueueData class holds metadata about a queue: ARN, URL, // name and type. List<QueueData> queues = List.of( new QueueData(wholeSaleQueueName, QueueType.FIFO), new QueueData(retailQueueName, QueueType.FIFO), new QueueData(analyticsQueueName, QueueType.Standard)); // Create queues. createQueues(queues); // Create a topic. String topicARN = createFIFOTopic(fifoTopicName); // Subscribe each queue to the topic. subscribeQueues(queues, topicARN); // Allow the newly created topic to send messages to the queues. addAccessPolicyToQueuesFINAL(queues, topicARN); // Publish a sample price update message with payload. publishPriceUpdate(topicARN, "{\"product\": 214, \"price\": 79.99}", "Consumables"); // Clean up resources. deleteSubscriptions(queues); deleteQueues(queues); deleteTopic(topicARN); } public static String createFIFOTopic(String topicName) { try { // Create a FIFO topic by using the SNS service client. Map<String, String> topicAttributes = Map.of( "FifoTopic", "true", "ContentBasedDeduplication", "false"); CreateTopicRequest topicRequest = CreateTopicRequest.builder() .name(topicName) .attributes(topicAttributes) .build(); CreateTopicResponse response = snsClient.createTopic(topicRequest); String topicArn = response.topicArn(); System.out.println("The topic ARN is" + topicArn); return topicArn; } catch (SnsException e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } return ""; } public static void subscribeQueues(List<QueueData> queues, String topicARN) { queues.forEach(queue -> { SubscribeRequest subscribeRequest = SubscribeRequest.builder() .topicArn(topicARN) .endpoint(queue.queueARN) .protocol("sqs") .build(); // Subscribe to the endpoint by using the SNS service client. // Only Amazon SQS queues can receive notifications from an Amazon SNS FIFO // topic. SubscribeResponse subscribeResponse = snsClient.subscribe(subscribeRequest); System.out.println("The queue [" + queue.queueARN + "] subscribed to the topic [" + topicARN + "]"); queue.subscriptionARN = subscribeResponse.subscriptionArn(); }); } public static void publishPriceUpdate(String topicArn, String payload, String groupId) { try { // Create and publish a message that updates the wholesale price. String subject = "Price Update"; String dedupId = UUID.randomUUID().toString(); String attributeName = "business"; String attributeValue = "wholesale"; MessageAttributeValue msgAttValue = MessageAttributeValue.builder() .dataType("String") .stringValue(attributeValue) .build(); Map<String, MessageAttributeValue> attributes = new HashMap<>(); attributes.put(attributeName, msgAttValue); PublishRequest pubRequest = PublishRequest.builder() .topicArn(topicArn) .subject(subject) .message(payload) .messageGroupId(groupId) .messageDeduplicationId(dedupId) .messageAttributes(attributes) .build(); final PublishResponse response = snsClient.publish(pubRequest); System.out.println(response.messageId()); System.out.println(response.sequenceNumber()); System.out.println("Message was published to " + topicArn); } catch (SnsException e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } }
  • 有关 API 的详细信息,请参阅《Amazon SDK for Java 2.x API 参考》中的以下主题。

Python
SDK for Python (Boto3)
注意

在 GitHub 上查看更多内容。在 Amazon 代码示例存储库 中查找完整示例,了解如何进行设置和运行。

创建 Amazon SNS FIFO 主题,将 Amazon SQS FIFO 队列和标准队列订阅到主题,并发布一条消息到主题。

def usage_demo(): """Shows how to subscribe queues to a FIFO topic.""" print("-" * 88) print("Welcome to the `Subscribe queues to a FIFO topic` demo!") print("-" * 88) sns = boto3.resource("sns") sqs = boto3.resource("sqs") fifo_topic_wrapper = FifoTopicWrapper(sns) sns_wrapper = SnsWrapper(sns) prefix = "sqs-subscribe-demo-" queues = set() subscriptions = set() wholesale_queue = sqs.create_queue( QueueName=prefix + "wholesale.fifo", Attributes={ "MaximumMessageSize": str(4096), "ReceiveMessageWaitTimeSeconds": str(10), "VisibilityTimeout": str(300), "FifoQueue": str(True), "ContentBasedDeduplication": str(True), }, ) queues.add(wholesale_queue) print(f"Created FIFO queue with URL: {wholesale_queue.url}.") retail_queue = sqs.create_queue( QueueName=prefix + "retail.fifo", Attributes={ "MaximumMessageSize": str(4096), "ReceiveMessageWaitTimeSeconds": str(10), "VisibilityTimeout": str(300), "FifoQueue": str(True), "ContentBasedDeduplication": str(True), }, ) queues.add(retail_queue) print(f"Created FIFO queue with URL: {retail_queue.url}.") analytics_queue = sqs.create_queue(QueueName=prefix + "analytics", Attributes={}) queues.add(analytics_queue) print(f"Created standard queue with URL: {analytics_queue.url}.") topic = fifo_topic_wrapper.create_fifo_topic("price-updates-topic.fifo") print(f"Created FIFO topic: {topic.attributes['TopicArn']}.") for q in queues: fifo_topic_wrapper.add_access_policy(q, topic.attributes["TopicArn"]) print(f"Added access policies for topic: {topic.attributes['TopicArn']}.") for q in queues: sub = fifo_topic_wrapper.subscribe_queue_to_topic( topic, q.attributes["QueueArn"] ) subscriptions.add(sub) print(f"Subscribed queues to topic: {topic.attributes['TopicArn']}.") input("Press Enter to publish a message to the topic.") message_id = fifo_topic_wrapper.publish_price_update( topic, '{"product": 214, "price": 79.99}', "Consumables" ) print(f"Published price update with message ID: {message_id}.") # Clean up the subscriptions, queues, and topic. input("Press Enter to clean up resources.") for s in subscriptions: sns_wrapper.delete_subscription(s) sns_wrapper.delete_topic(topic) for q in queues: fifo_topic_wrapper.delete_queue(q) print(f"Deleted subscriptions, queues, and topic.") print("Thanks for watching!") print("-" * 88) class FifoTopicWrapper: """Encapsulates Amazon SNS FIFO topic and subscription functions.""" def __init__(self, sns_resource): """ :param sns_resource: A Boto3 Amazon SNS resource. """ self.sns_resource = sns_resource def create_fifo_topic(self, topic_name): """ Create a FIFO topic. Topic names must be made up of only uppercase and lowercase ASCII letters, numbers, underscores, and hyphens, and must be between 1 and 256 characters long. For a FIFO topic, the name must end with the .fifo suffix. :param topic_name: The name for the topic. :return: The new topic. """ try: topic = self.sns_resource.create_topic( Name=topic_name, Attributes={ "FifoTopic": str(True), "ContentBasedDeduplication": str(False), }, ) logger.info("Created FIFO topic with name=%s.", topic_name) return topic except ClientError as error: logger.exception("Couldn't create topic with name=%s!", topic_name) raise error @staticmethod def add_access_policy(queue, topic_arn): """ Add the necessary access policy to a queue, so it can receive messages from a topic. :param queue: The queue resource. :param topic_arn: The ARN of the topic. :return: None. """ try: queue.set_attributes( Attributes={ "Policy": json.dumps( { "Version": "2012-10-17", "Statement": [ { "Sid": "test-sid", "Effect": "Allow", "Principal": {"AWS": "*"}, "Action": "SQS:SendMessage", "Resource": queue.attributes["QueueArn"], "Condition": { "ArnLike": {"aws:SourceArn": topic_arn} }, } ], } ) } ) logger.info("Added trust policy to the queue.") except ClientError as error: logger.exception("Couldn't add trust policy to the queue!") raise error @staticmethod def subscribe_queue_to_topic(topic, queue_arn): """ Subscribe a queue to a topic. :param topic: The topic resource. :param queue_arn: The ARN of the queue. :return: The subscription resource. """ try: subscription = topic.subscribe( Protocol="sqs", Endpoint=queue_arn, ) logger.info("The queue is subscribed to the topic.") return subscription except ClientError as error: logger.exception("Couldn't subscribe queue to topic!") raise error @staticmethod def publish_price_update(topic, payload, group_id): """ Compose and publish a message that updates the wholesale price. :param topic: The topic to publish to. :param payload: The message to publish. :param group_id: The group ID for the message. :return: The ID of the message. """ try: att_dict = {"business": {"DataType": "String", "StringValue": "wholesale"}} dedup_id = uuid.uuid4() response = topic.publish( Subject="Price Update", Message=payload, MessageAttributes=att_dict, MessageGroupId=group_id, MessageDeduplicationId=str(dedup_id), ) message_id = response["MessageId"] logger.info("Published message to topic %s.", topic.arn) except ClientError as error: logger.exception("Couldn't publish message to topic %s.", topic.arn) raise error return message_id @staticmethod def delete_queue(queue): """ Removes an SQS queue. When run against an AWS account, it can take up to 60 seconds before the queue is actually deleted. :param queue: The queue to delete. :return: None """ try: queue.delete() logger.info("Deleted queue with URL=%s.", queue.url) except ClientError as error: logger.exception("Couldn't delete queue with URL=%s!", queue.url) raise error
  • 有关 API 详细信息,请参阅《Amazon SDK for Python (Boto3) API 参考》中的以下主题。

SAP ABAP
SDK for SAP ABAP
注意

查看 GitHub,了解更多信息。在 Amazon 代码示例存储库 中查找完整示例,了解如何进行设置和运行。

创建 FIFO 主题并为此订阅 Amazon SQS FIFO 队列,然后向 Amazon SNS 主题发布消息。

" Creates a FIFO topic. " DATA lt_tpc_attributes TYPE /aws1/cl_snstopicattrsmap_w=>tt_topicattributesmap. DATA ls_tpc_attributes TYPE /aws1/cl_snstopicattrsmap_w=>ts_topicattributesmap_maprow. ls_tpc_attributes-key = 'FifoTopic'. ls_tpc_attributes-value = NEW /aws1/cl_snstopicattrsmap_w( iv_value = 'true' ). INSERT ls_tpc_attributes INTO TABLE lt_tpc_attributes. TRY. DATA(lo_create_result) = lo_sns->createtopic( iv_name = iv_topic_name it_attributes = lt_tpc_attributes ). DATA(lv_topic_arn) = lo_create_result->get_topicarn( ). ov_topic_arn = lv_topic_arn. " ov_topic_arn is returned for testing purposes. " MESSAGE 'FIFO topic created' TYPE 'I'. CATCH /aws1/cx_snstopiclimitexcdex. MESSAGE 'Unable to create more topics. You have reached the maximum number of topics allowed.' TYPE 'E'. ENDTRY. " Subscribes an endpoint to an Amazon Simple Notification Service (Amazon SNS) topic. " " Only Amazon Simple Queue Service (Amazon SQS) FIFO queues can be subscribed to an SNS FIFO topic. " TRY. DATA(lo_subscribe_result) = lo_sns->subscribe( iv_topicarn = lv_topic_arn iv_protocol = 'sqs' iv_endpoint = iv_queue_arn ). DATA(lv_subscription_arn) = lo_subscribe_result->get_subscriptionarn( ). ov_subscription_arn = lv_subscription_arn. " ov_subscription_arn is returned for testing purposes. " MESSAGE 'SQS queue was subscribed to SNS topic.' TYPE 'I'. CATCH /aws1/cx_snsnotfoundexception. MESSAGE 'Topic does not exist.' TYPE 'E'. CATCH /aws1/cx_snssubscriptionlmte00. MESSAGE 'Unable to create subscriptions. You have reached the maximum number of subscriptions allowed.' TYPE 'E'. ENDTRY. " Publish message to SNS topic. " TRY. DATA lt_msg_attributes TYPE /aws1/cl_snsmessageattrvalue=>tt_messageattributemap. DATA ls_msg_attributes TYPE /aws1/cl_snsmessageattrvalue=>ts_messageattributemap_maprow. ls_msg_attributes-key = 'Importance'. ls_msg_attributes-value = NEW /aws1/cl_snsmessageattrvalue( iv_datatype = 'String' iv_stringvalue = 'High' ). INSERT ls_msg_attributes INTO TABLE lt_msg_attributes. DATA(lo_result) = lo_sns->publish( iv_topicarn = lv_topic_arn iv_message = 'The price of your mobile plan has been increased from $19 to $23' iv_subject = 'Changes to mobile plan' iv_messagegroupid = 'Update-2' iv_messagededuplicationid = 'Update-2.1' it_messageattributes = lt_msg_attributes ). ov_message_id = lo_result->get_messageid( ). " ov_message_id is returned for testing purposes. " MESSAGE 'Message was published to SNS topic.' TYPE 'I'. CATCH /aws1/cx_snsnotfoundexception. MESSAGE 'Topic does not exist.' TYPE 'E'. ENDTRY.
  • 有关 API 详细信息,请参阅适用于 SAP ABAP 的 Amazon SDK 的 API 参考中的以下主题。

接收来自 FIFO 订阅的消息

现在,您可以在三个订阅的应用程序中接收价格更新。如 FIFO 主题示例使用案例 中所示,每个使用者应用程序的入口点是 Amazon SQS 队列,其相应的 Amazon Lambda 函数可以自动轮询。当 Amazon SQS 队列是 Lambda 函数的事件源时,Lambda 会根据需要扩展其轮询器队列,以高效地使用消息。

有关更多信息,请参阅 Amazon Lambda 开发人员指南中的将 Amazon Lambda 与 Amazon SQS 结合使用。有关编写自己的队列轮询器的信息,请参阅 Amazon Simple Queue Service 开发人员指南中的 Amazon SQS 标准和 FIFO 队列的建议Amazon Simple Queue Service API 参考 中的 ReceiveMessage

使用 Amazon CloudFormation

利用 Amazon CloudFormation,您可以使用模板文件,创建并配置 Amazon 资源的集合作为单一单元。本部分提供的模板示例,用于创建以下内容:

  • 分发价格更新的 Amazon SNS FIFO 主题

  • 为批发和零售应用程序提供这些更新的 Amazon SQS FIFO 队列

  • 用于存储记录的分析应用程序的 Amazon SQS 标准队列,可以查询这些记录以获取商业智能 (BI)

  • 将三个队列连接到主题的 Amazon SNS FIFO 订阅

  • 指定订阅者应用程序的筛选策略只接收他们需要的价格更新

注意

如果通过向主题发布消息来测试此代码示例,请确保您发布的是带 business 属性的消息。为属性值指定 retailwholesale。否则,消息将被筛选掉,且不会传递到订阅的队列中。

{ "AWSTemplateFormatVersion": "2010-09-09", "Resources": { "PriceUpdatesTopic": { "Type": "AWS::SNS::Topic", "Properties": { "TopicName": "PriceUpdatesTopic.fifo", "FifoTopic": true, "ContentBasedDeduplication": false, "ArchivePolicy": { "MessageRetentionPeriod": "30" } } }, "WholesaleQueue": { "Type": "AWS::SQS::Queue", "Properties": { "QueueName": "WholesaleQueue.fifo", "FifoQueue": true, "ContentBasedDeduplication": false } }, "RetailQueue": { "Type": "AWS::SQS::Queue", "Properties": { "QueueName": "RetailQueue.fifo", "FifoQueue": true, "ContentBasedDeduplication": false } }, "AnalyticsQueue": { "Type": "AWS::SQS::Queue", "Properties": { "QueueName": "AnalyticsQueue" } }, "WholesaleSubscription": { "Type": "AWS::SNS::Subscription", "Properties": { "TopicArn": { "Ref": "PriceUpdatesTopic" }, "Endpoint": { "Fn::GetAtt": [ "WholesaleQueue", "Arn" ] }, "Protocol": "sqs", "RawMessageDelivery": "false", "FilterPolicyScope": "MessageBody", "FilterPolicy": { "business": [ "wholesale" ] } } }, "RetailSubscription": { "Type": "AWS::SNS::Subscription", "Properties": { "TopicArn": { "Ref": "PriceUpdatesTopic" }, "Endpoint": { "Fn::GetAtt": [ "RetailQueue", "Arn" ] }, "Protocol": "sqs", "RawMessageDelivery": "false", "FilterPolicyScope": "MessageBody", "FilterPolicy": { "business": [ "retail" ] } } }, "AnalyticsSubscription": { "Type": "AWS::SNS::Subscription", "Properties": { "TopicArn": { "Ref": "PriceUpdatesTopic" }, "Endpoint": { "Fn::GetAtt": [ "AnalyticsQueue", "Arn" ] }, "Protocol": "sqs", "RawMessageDelivery": "false" } }, "SalesQueuesPolicy": { "Type": "AWS::SQS::QueuePolicy", "Properties": { "PolicyDocument": { "Statement": [ { "Effect": "Allow", "Principal": { "Service": "sns.amazonaws.com" }, "Action": [ "sqs:SendMessage" ], "Resource": "*", "Condition": { "ArnEquals": { "aws:SourceArn": { "Ref": "PriceUpdatesTopic" } } } } ] }, "Queues": [ { "Ref": "WholesaleQueue" }, { "Ref": "RetailQueue" }, { "Ref": "AnalyticsQueue" } ] } } } }

有关使用 Amazon CloudFormation 模板部署 Amazon 资源的更多信息,请参阅 Amazon CloudFormation 用户指南中的入门