AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Description: Sam application to deploy lambda.
Parameters: 
    FunctionNameParameter:
        Type: String
        Default: aws-db-workshop-ddb-stream-processor
        Description: Name of the Lambda function. Default is aws-db-workshop-ddb-stream-processor
    LambdaLayerNameParameter:
        Type: String
        Description: Name of the Lambda Layer.
    DatabaseName:
        Type: String
        Description: Name of the Amazon Aurora database containing the trips table
    DatabaseHostName:
        Type: String
        Description: Name of the host of the Amazon Aurora database containing the trips table
    DatabasePort:
        Type: Number
        Default: 5432
        Description: Port number of the Amazon Aurora database containing the trips table. Default is 5432
    DatabaseUserName:
        Type: String
        Description: User name of the Amazon Aurora database containing the trips table
    DatabasePassword:
        Type: String
        Description: Password of the Amazon Aurora database containing the trips table
    DDBTableName:
        Type: String
        Description: Name of the Amazon DynamoDB table. Default name is 'aws-db-workshop-trips'
        Default: aws-db-workshop-trips
    DDBStreamName:
        Type: String
        Description: Name of the Amazon DynamoDB stream
    SecurityGroupIds: 
        Type: List<AWS::EC2::SecurityGroup::Id>
        Description: Security Group IDs that Lambda will use
    VpcSubnetIds: 
        Type: List<AWS::EC2::Subnet::Id>
        Description: VPC Subnet IDs that Lambda will use (min 2 for HA)
Resources:
    PGConnectionLayer:
        Type: AWS::Serverless::LayerVersion
        Properties:
            LayerName: !Ref LambdaLayerNameParameter
            Description: Python PostgreSQL Connection Library
            ContentUri: dependencies/pg8000-layer.zip
            CompatibleRuntimes: 
                - python3.7
            LicenseInfo: 'BSD'
            RetentionPolicy: Delete
    TripsDDBStreamProcessorFunction:
        Type: 'AWS::Serverless::Function'
        Properties:
            FunctionName: !Ref FunctionNameParameter
            Handler: lambda_function.lambda_handler
            Runtime: python3.7
            CodeUri: .
            Description: Process completed taxi trip information from Amazon DynamoDB Streams and publishes the information to the trips table in Amazon Aurora database
            MemorySize: 3008
            Timeout: 900
            Layers:
                - !Ref PGConnectionLayer
            Events:
                Stream:
                    Type: DynamoDB
                    Properties: 
                        Stream: 
                            !Sub
                                - 'arn:${AWS::Partition}:dynamodb:${AWS::Region}:${AWS::AccountId}:table/${tableName}/${streamName}'
                                - {tableName: !Ref DDBTableName, streamName: !Ref DDBStreamName }
                        StartingPosition: LATEST
                        BatchSize: 10
                        Enabled: True
            VpcConfig:
                SecurityGroupIds: !Ref SecurityGroupIds
                SubnetIds : !Ref VpcSubnetIds
            Policies:
                - VPCAccessPolicy: {}
                - DynamoDBStreamReadPolicy: 
                    TableName: !Ref DDBTableName
                    StreamName: !Ref DDBStreamName
            Environment:
                Variables:
                    PG_DATABASE: !Ref DatabaseName
                    PG_HOST: !Ref DatabaseHostName
                    PG_PORT: !Ref DatabasePort
                    PG_USER: !Ref DatabaseUserName
                    PG_PASSWORD : !Ref DatabasePassword
            Tags:
                Name: !Ref FunctionNameParameter
                Purpose: 'aws-db-workshop'