AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Sample AWS SAM App for Cache Extension demo application

Globals:
  Function:
    Timeout: 10

Parameters:
  DatabaseName: 
    Type: String
    Description: Please enter a name for the database
    Default: "DynamoDbTable"
  ParameterValue:
    Type: String
    Description: Parameter value stored in Systems Manager Parameter Store
    Default: "MyParameter"
  SecretValue:
    Type: String
    Description: Secret value stored in AWS Secrets manager
    Default: "MySecret"
    NoEcho: true

      
Resources:
  # Sample Dynamo DB Table 
  DynamoDBTable: 
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: 
        Ref: DatabaseName
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - AttributeName: "pKey"
          AttributeType: "S"
        - AttributeName: "sKey"
          AttributeType: "S"
      KeySchema: 
        - AttributeName: "pKey"
          KeyType: "HASH"
        - AttributeName: "sKey"
          KeyType: "RANGE"

  # Sample SSM Parameter 
  SSMParameter:
    Type: AWS::SSM::Parameter
    Properties: 
      Name: "CacheExtensions_Parameter1"
      Type: "String"
      Value: 
        Ref: ParameterValue

  # Sample Secret record
  SecretRecord:
    Type: AWS::SecretsManager::Secret
    Properties:
      Name: "secret_info"
      SecretString: 
        Ref: SecretValue

  # Cache Extension - Lambda Function
  SampleFunction:
    Type: AWS::Serverless::Function
    DependsOn: 
      - DynamoDBTable
      - SSMParameter
    Properties:
      CodeUri: ../example-function/
      Handler: index.handler
      Runtime: nodejs12.x
      Environment: 
        Variables:
          databaseName: 
            Ref: DatabaseName
      Layers: 
        - !Ref CacheExtensionLayer
      Policies:
        - AmazonSSMReadOnlyAccess
        - DynamoDBReadPolicy:
            TableName: !Ref DynamoDBTable     
        - SSMParameterReadPolicy:
            ParameterName: !Ref SSMParameter
        - SSMParameterReadPolicy:
            ParameterName: !Ref SSMParameter
        - AWSSecretsManagerGetSecretValuePolicy:
            SecretArn: !Ref SecretRecord
  
  # Cache Extension - Lambda Layer
  CacheExtensionLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      ContentUri: ../bin/
      CompatibleRuntimes:
        - nodejs12.x
        - python3.8
        - java11
        - go1.x
      LayerName: Cache_Extension_Layer
      Description: Caching layer for DynamoDB
  
  # PutEntry Lambda function to put data to Dynamo DB Table 
  DatabaseEntry:
    Type: AWS::Serverless::Function
    DependsOn: 
      - DynamoDBTable
    Properties:
      Handler: index.handler
      Runtime: nodejs12.x
      Timeout: 15
      CodeUri: DatabaseEntryCode/
      Policies:
        - DynamoDBWritePolicy:
            TableName: !Ref DynamoDBTable

  # Custom Resource to invoke the PutEntry Lambda function   
  CustomResource:
    Type: Custom::LambdaInvoker
    DependsOn: DatabaseEntry
    Properties:
      ServiceToken: 
        Fn::GetAtt: [ DatabaseEntry , "Arn" ]
      DBName: 
        Ref: DatabaseName

Outputs:

  SampleCacheExtensionsFunction:
    Description: "Sample Cache Extensions Lambda Function ARN"
    Value: !GetAtt SampleFunction.Arn