06_conditions.yml

AWSTemplateFormatVersion: "2010-09-09"
Description: "RDS instance for various environments"

Parameters:
  Environment:
    Type: String
    AllowedValues:
      - dev
      - stage
      - prod

# https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/conditions-section-structure.html

Conditions:
  CreateProdResources: !Equals [ !Ref Environment, prod ] # yaml shorthand could be confusing (!=)
  
  CreateProdResourcesUsEast1: !And
    - !Equals [!Ref AWS::Region, "us-east-1"]
    - !Condition CreateProdResources
   # !Equals
   # Fn::Equals:


Resources:
  RdsDbInstance:
    Type: "AWS::RDS::DBInstance"
    DeletionPolicy: !If [CreateProdResources, "Snapshot", AWS::NoValue]
    Properties:
      AllocatedStorage: !If [CreateProdResources, 100, 10] # https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-conditions.html
      AllowMajorVersionUpgrade: false
      AutoMinorVersionUpgrade: true
      BackupRetentionPeriod: !If [CreateProdResources, 35, 5]
      DBClusterIdentifier: myDBCluster # reminder: see update requires replacement
      DBInstanceClass: !If [CreateProdResources, "db.m5.2xlarge", "db.m5.large"]
      Engine: postgres # https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBInstance.html
      EngineVersion: 9.6.6
      Iops: !If [CreateProdResources, 3000, 1000]
      MultiAZ: !Condition CreateProdResources
      StorageEncrypted: !Condition CreateProdResources # https://github.com/awsdocs/aws-cloudformation-user-guide/issues/3
      StorageType: io1
      Tags:
        - Name: Environment
          Value: !Ref Environment