能否使用导出栈的LogicalId？Fn::GetAtt调用报错问题

Let's break down why you're hitting this CloudFormation error and how to fix it step by step:

1. Verify the Logical ID Exists Exactly as Typed #

CloudFormation is case-sensitive when it comes to resource Logical IDs. First, double-check that your custom API Gateway resource is defined in the resources: Resources section of your serverless.yml with the exact ID rApiGatewayVehRestApi:

resources:
  Resources:
    rApiGatewayVehRestApi:
      Type: AWS::ApiGateway::RestApi
      Properties:
        Name: VehicleServiceAPI
        # Add any other required properties here (like Description, etc.)

If there's even a tiny typo (e.g., rapigatewayvehrestapi or RApiGatewayVehRestApi), CloudFormation won't recognize the resource.

2. Ensure You're Referencing the Resource Correctly #

When using Fn::GetAtt to fetch the RootResourceId, make sure the syntax is correct and the resource lives in the same CloudFormation template (which it should if you're defining it in your Serverless config):

# Example: Using RootResourceId in a child API resource
rApiGatewayVehResource:
  Type: AWS::ApiGateway::Resource
  Properties:
    ParentId:
      Fn::GetAtt: [rApiGatewayVehRestApi, RootResourceId] # Correct syntax
    RestApiId:
      Ref: rApiGatewayVehRestApi
    PathPart: "vehicles"

3. Avoid Conflicts with Serverless's Default API Gateway #

If you're using both a custom API Gateway (rApiGatewayVehRestApi) and Serverless's auto-generated default API (created when you add events to your functions), you might be accidentally referencing the wrong resource. To fix this:

• Disable the default API Gateway in your provider config (Serverless v3+):

  provider:
    name: aws
    runtime: nodejs6.10 # Quick note: This runtime is EOL—upgrade to nodejs18.x or later for security support
    stage: dev
    region: us-east-1 # Fill in your target region
    apiGateway:
      disableDefaultApi: true # Turns off the auto-generated API
  

• Make sure all your function events explicitly reference your custom API's RestApiId.

4. If Referencing an Exported Resource (Cross-Stack) #

If you're trying to pull the RootResourceId from a previously deployed stack where you exported rApiGatewayVehRestApi, you can't use Fn::GetAtt. Instead, use Fn::ImportValue:

First, confirm the original stack exports the value:

# In the original stack's serverless.yml
resources:
  Outputs:
    ApiGatewayRootResourceId:
      Value:
        Fn::GetAtt: [rApiGatewayVehRestApi, RootResourceId]
      Export:
        Name: ${self:service}-${self:stage}-RootResourceId

Then reference it in your current stack:

ParentId:
  Fn::ImportValue: ${self:service}-${self:stage}-RootResourceId

Common Pitfalls to Watch For #

• Typos in Logical IDs (case sensitivity is brutal here!)
• Trying to reference a resource defined in a different stack without using ImportValue
• Forgetting to disable the default API Gateway when using a custom one
• Using an outdated Node.js runtime (nodejs6.10 hasn't been supported since 2019—upgrade to avoid other issues!)

内容的提问来源于stack exchange，提问作者Abirami