Fn::If condition based on environment for Cloudformation Parameters - aws-cloudformation

Question

Based on the environment, I am trying to set the URL for a variable: It staging my URL should be https://staging.DNHostedZoneName , if prod - it should just be https://DNSHostedZoneName:
Here's my condition:
Conditions:
IsEnvProd: Fn::Equals [ !Ref Env, 'prod' ]
IsEnvStage: Fn::Equals [ !Ref Env, 'stage' ]
Here's where its been evaluated:
Environment:
- Name: NODE_ENV
Value: !Ref NodeEnv
- Fn::If:
- IsEnvStage
- Name: CORE_URL
Value:
Fn::Join:
- ""
- - "https://"
- "staging"
- "."
- !Ref DnsHostedZoneName
- Name: NCVCORE_URL
Value:
Fn::Join:
- ""
- - "https://"
- !Ref DnsHostedZoneName
I am getting the following error:
Template format error: Conditions can only be boolean operations on parameters and other conditions

Answer 1

Without the full template, it is difficult to try to recreate the issue, but here your snippets refactored with a possible error removed.
Adjusted the conditionals to use all shorthand.
Conditions:
IsEnvProd: !Equals [!Ref "Env", "prod"]
IsEnvStage: !Equals [!Ref "Env", "stage"]
There was an additional space in the YAML so that has been removed, and reformatted.
Environment:
- Name: "NODE_ENV"
Value: !Ref "NodeEnv"
- !If
- "IsEnvStage"
- Name: "CORE_URL"
Value: !Sub "https://staging.${DnsHostedZoneName}"
- Name: "NCVCORE_URL"
Value: !Sub "https://${DnsHostedZoneName}"

Answer 2

Usually the conditions defined are used as an attribute to an aws resource and you specify the name of the condition as a value. You can try https://krunal4amity.github.io - it is an online cloudformation template generator. It takes away a lot of such dreadful work.

Answer 3

You can try to orchestrate creation of specific resources using AWS::NoValue
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html
Below is taken from variables creation for LambdaFunction
Conditions:
IsProd: !Equals [!Ref Env, "production"]
Environment:
Variables:
USER: !If [IsProd, !GetAtt ...., Ref: AWS::NoValue]