amazon-web-services - 我可以仅在 SQS 中的消息计数达到目标值时触发 lambda 吗？

Question

我正在编写 AWS Lambda 以从 SQS 读取消息，然后在过滤后将一些消息保存到 S3。由于 80% 的消息会被过滤掉，我决定为 100000 条 SQS 消息编写一次 S3。

是否可以仅在 SQS 中的消息达到 10000 时才触发 Lambda？

Answer 1

在 AWS CloudWatch 的帮助下是可能的.

您可以配置一个 AWS CloudWatch 警报，一旦您的 SQS 队列收到 100000 条可见消息，它就会触发“AlarmAction”。如果出现“警报”，您将通知 SNS 主题，然后触发您的 AWS Lambda。

如果您正在使用 AWS CloudFormation它可能如下所示:

AWSTemplateFormatVersion: 2010-09-09
Resources:
  Queue:
    Type: AWS::SQS::Queue

  QueueVisibleMessagesTopic:
    Type: AWS::SNS::Topic

  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

  Lambda:
    Type: AWS::Lambda::Function
    Properties:
      Handler: handler.index
      Role: !GetAtt LambdaExecutionRole.Arn
      Runtime: nodejs8.10
      MemorySize: 128
      Timeout: 10

  LambdaSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint: !GetAtt Lambda.Arn
      Protocol: lambda
      TopicArn: !Ref QueueVisibleMessagesTopic

  LambdaSubscriptionPermissions:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt Lambda.Arn
      Action: lambda:InvokeFunction
      Principal: sns.amazonaws.com
      SourceArn: !Ref QueueVisibleMessagesTopic

  QueueVisibleMessagesAlarm:
    Type: AWS::CloudWatch::Alarm
    Properties:
      Namespace: AWS/SQS
      MetricName: ApproximateNumberOfMessagesVisible
      Dimensions:
        - Name: QueueName
          Value: !GetAtt Queue.QueueName
      Statistic: Sum
      Period: 300
      EvaluationPeriods: 1
      ComparisonOperator: GreaterThanOrEqualToThreshold
      Threshold: 100000
      AlarmActions:
        - !Ref QueueVisibleMessagesTopic