aws-cloudformation - AWS CDK参数错误: Value of property Parameters must be an object with String (or simple type) properties

Question

更新

接受的答案如下 Victor是正确的解决方法。

我联系了 AWS Support，确认了该错误。他们意识到了这个问题，并将我链接到这两个链接以跟踪此案例。

... During my investigation and replication of the issue, I noticed that this issue seems to be with how CDK handles the VPCEndpoint resource as its parameters include a list of DNS entries with them.
This is a known issue with the resource:
https://github.com/aws/aws-cdk/issues/5897
https://github.com/aws/aws-cdk/issues/9488

在此之前，如果您遇到此问题，解决方案就在这里。

---

原始问题

我期望能够开箱即用地使用 Fn.select 和 Fn.split，但是下面的代码有一些非常奇怪的行为，想知道我是否在做一些意想不到的事情。

我希望输出包含声明的函数fn::Select [1, fn:split [ fn:select [0, getAttr [ Something ] ] ] ]

但实际上我看到的只是getAttr [something]，这导致属性参数的值必须是具有String(或简单类型)属性的对象 部署期间

感谢任何帮助

这是重现错误的代码

#!/usr/bin/env node
import 'source-map-support/register';
import {App, aws_ec2, aws_lambda, Fn, NestedStack, NestedStackProps, Stack, StackProps } from 'aws-cdk-lib';
import { Construct } from 'constructs';

const app = new App();

export class MainStack extends Stack {
  constructor(scope: Construct, id: string, props: StackProps) {
    super(scope, id, props);
    new Nested1(this, 'first', {})
  }
}
export class Nested1 extends NestedStack {
  constructor(scope: Construct, id: string, props: NestedStackProps) {
    super(scope, id, props);

    const vpc = new aws_ec2.Vpc(this, 'vpc', {
      subnetConfiguration: [{
        cidrMask: 28,
        name: 'private-test-bug',
        subnetType: aws_ec2.SubnetType.PRIVATE_ISOLATED,
      }]
    })
    const apiEndpoint = new aws_ec2.InterfaceVpcEndpoint(this, `apiEndpoint`, {
      service: {
        name: 'com.amazonaws.eu-central-1.execute-api',
        port: 443,
      },
      vpc: vpc,
      subnets: {
        subnets: vpc.isolatedSubnets,
        onePerAz: true
      },
      open: true,
      privateDnsEnabled: false,
    });
    //  BUG IS HERE
    new Nested2(this, 'nested2', { VpcEndpoint: apiEndpoint }) // CDK should handle and parse the reference, but it dont
  }
}

export interface Nested2StackProps extends NestedStackProps { VpcEndpoint: aws_ec2.InterfaceVpcEndpoint; }
export class Nested2 extends NestedStack {
  constructor(scope: Construct, id: string, props: Nested2StackProps) {
    super(scope, id, props);

    const lambda = new aws_lambda.Function(this, 'lambda-function', {
      code: aws_lambda.Code.fromInline(`exports.handler = (event, context) => { console.log(process.env.dns_name) }`),
      handler: 'index.handler',
      runtime: aws_lambda.Runtime.NODEJS_16_X,
      environment: { dns_name: Fn.select(1, Fn.split(':', Fn.select(0, props.VpcEndpoint.vpcEndpointDnsEntries))) } // USAGE IS HERE
    })
  }
}

new MainStack (app, 'TestStack', {
  env: { account: process.env.CDK_DEFAULT_ACCOUNT, region: process.env.CDK_DEFAULT_REGION },
});

Answer 1

简而言之，它看起来像是 CDK 中的一个错误。 CDK 尝试将数组作为参数发送到嵌套模板。相反，它应该连接数组并将其作为字符串传递。

我建议解决该问题。我将代码分成两部分。首先，我解释一下这个想法并展示一些代码片段。最后，我展示完整的解决方案。

我们在嵌套堆栈中定义参数，如下所示:

  const stack = new NestedStack(scope, id, {
    parameters: {
      VpcEndpointDnsEntries: props.VpcEndpointDnsEntries
    },
  })

在代码中，我们为此参数创建一个对象，并使用它来获取参数值。

  const endpoints = new CfnParameter(stack, 'VpcEndpointDnsEntries', {
    type: 'List<String>',
    description: 'List of entries.'
  })

// Read the value:

const strings = endpoints.valueAsList

在最后一步中，我们几乎像往常一样将参数传递给嵌套堆栈，只是我们加入了字符串。

  createNestedStack(stack, 'NestedStack',
    { VpcEndpointDnsEntries: Fn.join(',', apiEndpoint.vpcEndpointDnsEntries) })

请注意，lambda 函数不起作用，它会引发运行时异常。否则，堆栈和嵌套堆栈将正常部署。

请在下面找到完整的代码。

抱歉，我现在真的很着急。我计划今晚修复语法并更新答案。

import { App, CfnParameter, Fn, NestedStack, Stack } from 'aws-cdk-lib'
import { env } from 'process'
import { InterfaceVpcEndpoint, Vpc } from 'aws-cdk-lib/aws-ec2'
import { Code, Function, Runtime } from 'aws-cdk-lib/aws-lambda'

function createMainStack (scope, id, props) {
  const stack = new Stack(scope, id, props)

  const vpc = Vpc.fromLookup(stack, 'Vpc', { vpcName: 'WarehousePrinters' })

  const apiEndpoint = new InterfaceVpcEndpoint(stack, `ApiEndpoint`, {
    service: {
      name: 'com.amazonaws.eu-west-1.execute-api',
      port: 443,
    },
    vpc,
    subnets: { subnets: vpc.privateSubnets, onePerAz: true },
    open: true,
    privateDnsEnabled: false,
  })

  createNestedStack(stack, 'NestedStack', { VpcEndpointDnsEntries: Fn.join(',', apiEndpoint.vpcEndpointDnsEntries) })

  return stack
}

function createNestedStack (scope, id, props) {
  const stack = new NestedStack(scope, id, {
    parameters: {
      VpcEndpointDnsEntries: props.VpcEndpointDnsEntries
    },
  })

  const endpoints = new CfnParameter(stack, 'VpcEndpointDnsEntries', {
    type: 'List<String>',
    description: 'List of entries.'
  })

  new Function(stack, 'LambdaFunction', {
    code: Code.fromInline(`export function handler = () => console.log(env.dns_name)`),
    handler: 'index.handler',
    runtime: Runtime.NODEJS_16_X,
    environment: {
      dns_name: Fn.select(1, Fn.split(':', Fn.select(0, endpoints.valueAsList)))
    }
  })

  return stack
}

const app = new App()
createMainStack(app, 'MainStack', {
  env: { account: env.CDK_DEFAULT_ACCOUNT, region: env.CDK_DEFAULT_REGION }
})