AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: APPNAMEHERE Lambda (ALB)

Parameters:

  RailsEnv:
    Type: String
    Default: production
    AllowedValues:
      - staging
      - production
  VpcId:
    Type: AWS::EC2::VPC::Id
  Subnets:
    Type: List<AWS::EC2::Subnet::Id>

Resources:

  RailsLoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Name: APPNAMEHERE
      Scheme: internet-facing
      Subnets: !Ref Subnets
      SecurityGroups:
        - !Ref RailsSecurityGroup

  RailsLoadBalancerTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    DependsOn: RailsFunctionInvokePermission
    Properties:
      TargetType: lambda
      TargetGroupAttributes:
        - Key: lambda.multi_value_headers.enabled
          Value: true
      Targets:
        - Id: !GetAtt RailsFunction.Arn

  RailsLoadBalancerHttpListener:
    Type: 'AWS::ElasticLoadBalancingV2::Listener'
    Properties:
      DefaultActions:
        - TargetGroupArn: !Ref RailsLoadBalancerTargetGroup
          Type: forward
      LoadBalancerArn: !Ref RailsLoadBalancer
      Port: 80
      Protocol: HTTP

  RailsSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Allow HTTP
      VpcId: !Ref VpcId
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0

  RailsFunctionInvokePermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt RailsFunction.Arn
      Action: 'lambda:InvokeFunction'
      Principal: elasticloadbalancing.amazonaws.com

  RailsFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: .
      Handler: app.handler
      Runtime: ruby2.5
      MemorySize: 512
      Timeout: 30
      Environment:
        Variables:
          RAILS_ENV: !Ref RailsEnv
      FunctionName: !Join [ '', [ 'APPNAMEHERE-', !Ref RailsEnv, '-', !Ref 'AWS::Region' ] ]
      AutoPublishAlias: live

Outputs:

  RailsLoadBalancerDNSNAme:
    Description: Application Load Balancer DNS Name
    Value: !GetAtt RailsLoadBalancer.DNSName

  RailsFunctionArn:
    Description: Lambda ARN
    Value: !GetAtt RailsFunction.Arn