AWSTemplateFormatVersion: 2010-09-09
Description: DynamoDB Backup
Resources:
  SourceS3Bucket:
    Type: 'AWS::S3::Bucket'
    Properties:
        BucketEncryption:
            ServerSideEncryptionConfiguration:
                - ServerSideEncryptionByDefault:
                    SSEAlgorithm: 'AES256'
        VersioningConfiguration:
            Status: Enabled
  
  DynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties: 
      TableName: !Sub 'order_transaction_${AWS::StackName}'
      AttributeDefinitions: 
        - AttributeName: order_id
          AttributeType: S
        - AttributeName: item_id
          AttributeType: S
      KeySchema: 
        - AttributeName: order_id
          KeyType: HASH
        - AttributeName: item_id
          KeyType: RANGE
      ProvisionedThroughput: 
        ReadCapacityUnits: 5
        WriteCapacityUnits: 5
  
  ProcessLambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - lambda.amazonaws.com
          Action:
          - sts:AssumeRole
      Policies:
        - PolicyName: allowLambdaLogs
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
            - Effect: Allow
              Action:
              - 'logs:CreateLogGroup'
              - 'logs:CreateLogStream'
              - 'logs:PutLogEvents'
              Resource: arn:aws:logs:*:*:*

  CsvToDDBLambdaRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - lambda.amazonaws.com
                - s3.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole'
        - 'arn:aws:iam::aws:policy/AWSLambdaInvocation-DynamoDB'
        - 'arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess'
      Policies:
        - PolicyName: policyname
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Resource: !GetAtt DynamoDBTable.Arn
                Action:
                  - 'dynamodb:PutItem'
                  - 'dynamodb:BatchWriteItem'
  CsvToDDBLambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      Handler: index.lambda_handler
      Role: !GetAtt 
        - CsvToDDBLambdaRole
        - Arn
      Code:
        ZipFile: !Join 
          - |+

          - - import json
            - import boto3
            - import os
            - import csv
            - import codecs
            - import sys
            - ''
            - s3 = boto3.resource('s3')
            - dynamodb = boto3.resource('dynamodb')
            - ''
            - 'bucket = os.environ[''bucket'']'
            - 'key = os.environ[''key'']'
            - 'tableName = os.environ[''table'']'
            - ''
            - 'def lambda_handler(event, context):'
            - ''
            - ''
            - '   #get() does not store in memory'
            - '   try:'
            - '       obj = s3.Object(bucket, key).get()[''Body'']'
            - '   except:'
            - '       print("S3 Object could not be opened. Check environment variable. ")'
            - '   try:'
            - '       table = dynamodb.Table(tableName)'
            - '   except:'
            - '       print("Error loading DynamoDB table. Check if table was created correctly and environment variable.")'
            - ''
            - '   batch_size = 100'
            - '   batch = []'
            - ''
            - '   #DictReader is a generator; not stored in memory'
            - '   for row in csv.DictReader(codecs.getreader(''utf-8'')(obj)):'
            - '      if len(batch) >= batch_size:'
            - '         write_to_dynamo(batch)'
            - '         batch.clear()'
            - ''
            - '      batch.append(row)'
            - ''
            - '   if batch:'
            - '      write_to_dynamo(batch)'
            - ''
            - '   return {'
            - '      ''statusCode'': 200,'
            - '      ''body'': json.dumps(''Uploaded to DynamoDB Table'')'
            - '   }'
            - ''
            - ''
            - 'def write_to_dynamo(rows):'
            - '   try:'
            - '      table = dynamodb.Table(tableName)'
            - '   except:'
            - '      print("Error loading DynamoDB table. Check if table was created correctly and environment variable.")'
            - ''
            - '   try:'
            - '      with table.batch_writer() as batch:'
            - '         for i in range(len(rows)):'
            - '            batch.put_item('
            - '               Item=rows[i]'
            - '            )'
            - '   except:'
            - '      print("Error executing batch_writer")'
      Runtime: python3.7
      Timeout: 900
      MemorySize: 3008
      Environment:
        Variables:
          bucket: !Ref SourceS3Bucket
          key: 'order_data.csv'
          table: !Ref DynamoDBTable
Outputs:
  SourceS3Bucket:
    Value: !Ref SourceS3Bucket