AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  Timestream integration

Parameters:
  ParamBinaryDecoderName:
    Type: String
    Default: sample_device
    Description: Name of binary decoder as configured in src-iotrule-transformation/app.py
    
  TopicError:
    Type: String
    Default: dt/lorawanerror
    Description: Name of MQTT topic for to publish IoT Rule action error messages

  TopicDebug:
    Type: String
    Default: debug
    Description: 
        |
        Prefix of a MQTT topic to publish debugging information.'

Resources:
  ############################################################################################
  # Payload transformation Lambda function to be called from AWS IoT Core. This function will refer to 
  # layer "DecoderLayer" to include the necessary decoding libraries 
  ############################################################################################

  WriteLoRaWANDataToTimestreamFunction:
    Type: AWS::Serverless::Function
    Name: !Sub '${AWS::StackName}-WriteLoRaWANDataToTimestreamFunction'
    Properties:
      CodeUri: src-lambda-write-to-timestream
      Handler: app.lambda_handler
      Runtime: python3.7
      Timeout: 10
      Environment:
        Variables:
          DB_NAME: !Ref TimestreamDatabase
          TABLE_NAME_TELEMETRY: !Select [ "1", !Split [ "|" , !Ref TimestreamTableTelemetry]]
          TABLE_NAME_METADATA: !Select [ "1", !Split [ "|" , !Ref TimestreamTableMetadata]]
      Policies:
         -  Statement:
            - Sid: Pol1
              Effect: Allow
              Action:
                - timestream:WriteRecords
              Resource: !GetAtt TimestreamTableTelemetry.Arn
            - Sid: Pol2
              Effect: Allow
              Action:
                - timestream:WriteRecords
              Resource: !GetAtt TimestreamTableMetadata.Arn
            - Sid: Pol3
              Effect: Allow
              Action:
                - timestream:DescribeEndpoints
              Resource: "*"

  WriteLoRaWANDataToTimestreamFunctionPermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt WriteLoRaWANDataToTimestreamFunction.Arn
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com


  TransformLoRaWANBinaryPayloadForTimestreamFunction:
    Type: AWS::Serverless::Function
    Name: !Sub '${AWS::StackName}TransformLoRaWANBinaryPayloadForTimestreamFunction'
    Properties:
      CodeUri: src-lambda-transform
      Handler: app.lambda_handler
      Runtime: python3.7
      Layers:  
        - Ref:  LoRaWANPayloadDecoderLayer
      Timeout: 10

  TransformLoRaWANBinaryPayloadForTimestreamFunctionPermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !GetAtt TransformLoRaWANBinaryPayloadForTimestreamFunction.Arn
      Action: lambda:InvokeFunction
      Principal: iot.amazonaws.com


              

  ############################################################################################
  # LAYERS
  ############################################################################################
  LoRaWANPayloadDecoderLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: !Sub '${AWS::StackName}-LoRaWANPayloadDecoderLayer'
      Description: Payload decoders for LoRaWAN devices
      ContentUri: src-layer-payload-decoders
      CompatibleRuntimes:
        - python3.8
      RetentionPolicy: Retain
  
  ############################################################################################
  # This IoT Rule converts a binary message to a JSON message using a payload decoder, and then 
  # writes the payload of message and metadata into a Amazon Timestream database.
  # Incoming message topic: 
  # dt/lorawanbinary/<application id>/<device type id>/<device id>
  # Example:
  # dt/lorawanbinary/moisture/dragino_lht65/12345678
  ############################################################################################
  
  WriteLoRaWANDataToTimestreamRule:

    Type: "AWS::IoT::TopicRule"
    Properties:
      RuleName: !Sub '${AWS::StackName}_WriteLoRaWANDataToTimestream_${ParamBinaryDecoderName}'
      TopicRulePayload:
        AwsIotSqlVersion: "2016-03-23"
        RuleDisabled: false

        Sql:
            !Sub 
              - |
                SELECT aws_lambda("${LambdaARN}",
                                  {"PayloadDecoderName": "${ParamBinaryDecoderName}", 
                                  "PayloadData":PayloadData, 
                                  "WirelessDeviceId": DeviceId, 
                                   "WirelessMetadata": WirelessMetadata}) as transformed_message, 
                        WirelessDeviceId as transformed_message.WirelessDeviceId,                                   
                        WirelessMetadata.LoRaWAN.DevEui as transformed_message.DevEui,
                        WirelessDeviceId as lns_message.WirelessDeviceId, 
                        WirelessMetadata as lns_message.WirelessMetadata,
                        PayloadData as lns_message.PayloadData
              - { LambdaARN: !GetAtt TransformLoRaWANBinaryPayloadForTimestreamFunction.Arn }      
        Actions:
            - Lambda:
                FunctionArn:  !GetAtt WriteLoRaWANDataToTimestreamFunction.Arn
            - Republish:
                RoleArn: !GetAtt StoreLoRaWANPayloadInTimestreamRuleRepublishActionRole.Arn
                Topic:
                  !Join [
                      "",
                      [
                        !Ref TopicDebug
                      ],
                    ]
                Qos: 0

        ErrorAction:
            Republish:
              RoleArn: !GetAtt StoreLoRaWANPayloadInTimestreamRuleRepublishActionRole.Arn
              Topic: !Ref TopicError
              Qos: 0

  
  StoreLoRaWANPayloadInTimestreamRuleRepublishActionRole:
      Type: "AWS::IAM::Role"
      Properties:
        AssumeRolePolicyDocument:
          Version: 2012-10-17
          Statement:
            - Effect: Allow
              Principal:
                Service:
                  - iot.amazonaws.com
              Action:
                - "sts:AssumeRole"
        Policies:
          - PolicyName: root
            PolicyDocument:
              Version: 2012-10-17
              Statement:
                - Effect: Allow
                  Action: iot:Publish
                  Resource:
                    !Join [
                      "",
                      [
                        "arn:aws:iot:",
                        !Ref "AWS::Region",
                        ":",
                        !Ref "AWS::AccountId",
                        ":topic/",
                        !Ref TopicDebug,
                        "/*"
                      ],
                    ]
                - Effect: Allow
                  Action: iot:Publish
                  Resource:
                    !Join [
                      "",
                      [
                        "arn:aws:iot:",
                        !Ref "AWS::Region",
                        ":",
                        !Ref "AWS::AccountId",
                        ":topic/",
                        !Ref TopicError
                      ],
                    ]



  

  TimestreamDatabase:
    Type: AWS::Timestream::Database
    Properties:
      DatabaseName: !Sub ${AWS::StackName}LoRaWANDatabase

  TimestreamTableTelemetry:
    Type: AWS::Timestream::Table
    Properties:
      TableName: !Sub ${AWS::StackName}LoRaWANTelemetryTable
      DatabaseName:
        Ref: TimestreamDatabase
      RetentionProperties:
        MemoryStoreRetentionPeriodInHours: '24'
        MagneticStoreRetentionPeriodInDays: '5'
  
  TimestreamTableMetadata:
      Type: AWS::Timestream::Table
      Properties:
        TableName: !Sub ${AWS::StackName}LoRaWANMetadataTable
        DatabaseName:
          Ref: TimestreamDatabase
        RetentionProperties:
          MemoryStoreRetentionPeriodInHours: '24'
          MagneticStoreRetentionPeriodInDays: '5'

        
Outputs:
  DatabaseName:
    Description: "Database Name"
    Value: !Ref TimestreamDatabase
  TableNameTelemetry:
    Description: "Table Name for Telemetry "
    Value: !Select [ "1", !Split [ "|" , !Ref TimestreamTableTelemetry]]
  TableNameMetadata:
    Description: "Table Name for Metadata"
    Value: !Select [ "1", !Split [ "|" , !Ref TimestreamTableMetadata]]
  WriteLoRaWANDataToTimestreamFunctionArn:
    Value: !Ref WriteLoRaWANDataToTimestreamFunction
  TransformLoRaWANBinaryPayloadForTimestreamFunctionArn:
    Value: !Ref TransformLoRaWANBinaryPayloadForTimestreamFunction