Addon template to create an Elasticache cluster

redis.yml

Parameters:
  App:
    Type: String
    Description: Your application's name.
  Env:
    Type: String
    Description: The environment name your service, job, or workflow is being deployed to.
  Name:
    Type: String
    Description: The name of the service, job, or workflow being deployed.

Resources:
  # Subnet group to control where the Redis gets placed
  RedisSubnetGroup:
    Type: AWS::ElastiCache::SubnetGroup
    Properties:
      Description: Group of subnets to place Redis into
      SubnetIds: !Split [ ',', { 'Fn::ImportValue': !Sub '${App}-${Env}-PrivateSubnets' } ]
  
  # Security group to add the Redis cluster to the VPC,
  # and to allow the Fargate containers to talk to Redis on port 6379
  RedisSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: "Redis Security Group"
      VpcId: { 'Fn::ImportValue': !Sub '${App}-${Env}-VpcId' }
  
  # Enable ingress from other ECS services created within the environment.
  RedisIngress:
    Type: AWS::EC2::SecurityGroupIngress
    Properties:
      Description: Ingress from Fargate containers
      GroupId: !Ref 'RedisSecurityGroup'
      IpProtocol: tcp
      FromPort: 6379
      ToPort: 6379
      SourceSecurityGroupId: { 'Fn::ImportValue': !Sub '${App}-${Env}-EnvironmentSecurityGroup' }

  # The cluster itself.
  Redis:
    Type: AWS::ElastiCache::CacheCluster
    Properties:
      Engine: redis
      CacheNodeType: cache.m4.large
      NumCacheNodes: 1
      CacheSubnetGroupName: !Ref 'RedisSubnetGroup'
      VpcSecurityGroupIds:
        - !GetAtt 'RedisSecurityGroup.GroupId'

  # Redis endpoint stored in SSM so that other services can retrieve the endpoint.
  RedisEndpointAddressParam:
    Type: AWS::SSM::Parameter
    Properties:
      Name: !Sub '/${App}/${Env}/${Name}/redis'   # Other services can retrieve the endpoint from this path.
      Type: String
      Value: !GetAtt 'Redis.RedisEndpoint.Address'

Outputs:
  RedisEndpoint:
    Description: The endpoint of the redis cluster
    Value: !GetAtt 'Redis.RedisEndpoint.Address'