aws cloudformation 如何在映射块中使用条件？

Question

Hi I have the following mapping that I wanted to use condition statements in:

Conditions:
  IsChinaSite:
    !Equals [!Ref SiteType, 'ChinaSite']


Mappings:
  Environment2Env:
    Develop:
      ENV: Dev
      ApiRegion: us-east-1  # There is no test CN data so we are going to keep using test US data in test envs
    Test:
      ENV: Qual
      ApiRegion: us-east-1
    Staging:
      ENV: Test
      ApiRegion: us-east-1
    Production:
      ENV: Prod
      FleetApiRegion: !If[IsChinaSite, ap-northeast-1, us-east-1]

As you can see I am trying to sigv4 sign to a different region depending on the value of an input param in the prod version of my site. However after reading the docs it seems you cant use condition statements in the Mappings block of your template. How/where should I go about checking the IsChinaSite condition?

Answer 1

I image you can mix an If and FindInMap to get the result you want

Conditions:
  IsChinaSite:
    !Equals [!Ref SiteType, 'ChinaSite']


Mappings:
  Environment2Env:
    Develop:
      ENV: Dev
      ApiRegion: us-east-1
    Test:
      ENV: Qual
      ApiRegion: us-east-1
    Staging:
      ENV: Test
      ApiRegion: us-east-1
    USProduction:
      Env: Prod
      ApiRegion: us-east-1
    ChinaProduction:
      ENV: Prod
      ApiRegion: ap-northeast-1

Resources:
  Ec2Instance:
    Type: AWS::EC2::Instance
    Properties:
      AvailabilityZone:
        !If
          - IsChainSite
          - !FindInMap [Environment2Env, ChinaProduction, ApiRegion]
          - !FindInMap [Environment2Env, USProduction, ApiRegion]

Answer 2

Ended up having to just split out the regions into their own mapping under each env. Wound up with this:

Mappings:
  Environment2Env:
    Develop:
      ENV: Dev
    Test:
      ENV: Qual
    Staging:
      ENV: Test
    USProduction:
      Env: Prod
    ChinaProduction:
      ENV: Prod

  Develop:
    ROW: us-east-1
    ChinaSite: us-east-1
  Test:
    ROW: us-east-1
    ChinaSite: us-east-1
  Staging:
    ROW: us-east-1
    ChinaSite: us-east-1
  Production:
    ROW: us-east-1
    ChinaSite: ap-northeast-1

This solution worked for me because thankfully I was only parameterizing with 2 dimensions (the max/min dimensions required to make a cloudformation mapping) but that was kind of dumb luck. Had I been in a situation where I needed to deploy in multiple envs, with multiple types of sites, AND each type of site had some sort of sub-type, I would have been scr---d. I still think the right answer here is something that can support x^n number of dimensions so I don't think I am going to accept my own answer but I wanted to share my solution to my problem.