amazon-web-services - 定义 cloudFormation 脚本时，无法从 lambda 函数中的环境访问 SNS_TOPIC_ARN 值

Question

这是我的云形成脚本

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs12.x
      Events:
        HelloWorldApi:
          Type: Api
          Properties:
            Path: /
            Method: GET
    Policies:
      - SNSPublishMessagePolicy:
          TopicName: !GetAtt HelloWorldTopic.TopicName
    Environment:
      Variables:
        SNS_TOPIC_ARN: !Ref HelloWorldTopic
  HelloWorldTopic:
    Type: AWS::SNS::Topic
    Properties:
      Subscription:
        - Endpoint: benja<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="197470776d757c7c2f2929597e74787075377a7674" rel="noreferrer noopener nofollow">[email protected]</a>
          Protocol: email`enter code here`

这是我的 Lambda 函数:

const aws = require('aws-sdk');
aws.config.update({ region: 'eu-west-2' });
const sns = new aws.SNS({ region: 'us-east-1' });

exports.handler = async function (event, context) {
  console.log('SNS_TOPIC_ARN: ' + process.env.SNS_TOPIC_ARN);
  const params = {
    Message: 'Hello World!',
    Subject: 'SNS Notification from Lambda',
    TopicArn: process.env.SNS_TOPIC_ARN,
  };
  try {
    await sns.publish(params).promise();
    return { statusCode: 200, body: 'Message sent' };
  } catch (err) {
    return { statusCode: 500, body: JSON.stringify(err) };
  }
};

每次发出 API 请求时，由于某种原因，我都会收到一条错误消息:“参数无效:TopicArn 或 TargetArn 原因:所需参数没有值”。

如有任何建议，我们将不胜感激。

Answer 1

我注意到模板存在一些问题。

Environment 和 Policies 应位于 Properties 下，就在 Type 下方。目前其外部Properties

此外，我相信 Policies 格式有点错误。通常情况下是这样的

Policies:
- AWSLambdaExecute
- Version: '2012-10-17' 
  Statement:
    - Effect: Allow
      Action:
        - s3:GetObject
        - s3:GetObjectACL
      Resource: 'arn:aws:s3:::my-bucket/*'

在您的情况下，这将是 sns:publish 以及类似的内容