template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
    This template deploys a code sample for testing an asynchronous architecture using Python.

Parameters:
  DeployTestResources:
    Description: The parameter instructs the template whether or not to deploy test resources to your environment.
    Default: "True"
    Type: String
    AllowedValues:
      - "True"
      - "False"
    ConstraintDescription: Allowed values are True and False

Conditions:
  CreateTestResources: !Equals [!Ref DeployTestResources, "True"]

Globals: # https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-specification-template-anatomy-globals.html
    Function:
        Timeout: 15
        MemorySize: 256
        Runtime: python3.9
        Tracing: Active # https://docs.aws.amazon.com/lambda/latest/dg/lambda-x-ray.html
        # Embed Lambda Powertools as a shared Layer
        # See: https://awslabs.github.io/aws-lambda-powertools-python/latest/#lambda-layer
        Layers: # 
            - !Sub arn:aws:lambda:${AWS::Region}:017000801446:layer:AWSLambdaPowertoolsPython:9
        Environment:
            Variables:
                DESTINATION_BUCKET: 
                  !Sub "async-destination-${AWS::StackName}-${AWS::AccountId}"
                RESULTS_TABLE: 
                  !Sub "async-results-${AWS::StackName}-${AWS::AccountId}"                
                # Powertools env vars: https://awslabs.github.io/aws-lambda-powertools-python/#environment-variables
                LOG_LEVEL: INFO
                POWERTOOLS_LOGGER_SAMPLE_RATE: 0.1
                POWERTOOLS_LOGGER_LOG_EVENT: true
                POWERTOOLS_METRICS_NAMESPACE: MyServerlessApplication
                POWERTOOLS_SERVICE_NAME: async

Resources:
  SourceBucket:
    Type: AWS::S3::Bucket
    UpdateReplacePolicy: Delete
    Properties:
      BucketName: 
        !Sub "async-source-${AWS::StackName}-${AWS::AccountId}"
      BucketEncryption:
        ServerSideEncryptionConfiguration:
        - ServerSideEncryptionByDefault:
            SSEAlgorithm: AES256
      PublicAccessBlockConfiguration:
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true

  DestinationBucket:
    Type: AWS::S3::Bucket
    UpdateReplacePolicy: Delete
    Properties:
      BucketName:
        !Sub "async-destination-${AWS::StackName}-${AWS::AccountId}"
      BucketEncryption:
        ServerSideEncryptionConfiguration:
        - ServerSideEncryptionByDefault:
            SSEAlgorithm: AES256
      PublicAccessBlockConfiguration:
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true

  ToUppercaseTextTransformer:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: 
        !Sub "ToUppercaseTextTransformer-${AWS::StackName}-${AWS::AccountId}"
      CodeUri: src/
      Handler: app.handler
      Policies:
        - S3ReadPolicy:
            BucketName: 
              !Sub "async-source-${AWS::StackName}-${AWS::AccountId}"
        - S3CrudPolicy:
            BucketName: 
              !Sub "async-destination-${AWS::StackName}-${AWS::AccountId}"
      Events:
        FileUpload:
          Type: S3
          Properties:
            Bucket: !Ref SourceBucket
            Events: s3:ObjectCreated:*
            Filter:
              S3Key:
                Rules:
                  - Name: suffix
                    Value: '.txt'

  AsyncTransformTestResultsTable:
    Type: AWS::DynamoDB::Table
    Condition: CreateTestResources
    Properties: 
      TableName: 
        !Sub "async-results-${AWS::StackName}-${AWS::AccountId}"
      AttributeDefinitions: 
        - AttributeName: id
          AttributeType: S
      KeySchema: 
        - AttributeName: id
          KeyType: HASH
      ProvisionedThroughput: 
        ReadCapacityUnits: 2
        WriteCapacityUnits: 2

  DestinationBucketListener:
    Type: AWS::Serverless::Function
    Condition: CreateTestResources
    Properties:
      FunctionName: 
        !Sub "DestinationBucketListener-${AWS::StackName}-${AWS::AccountId}"
      CodeUri: tests/integration
      Handler: event_listener_lambda.handler
      Policies:
        - DynamoDBWritePolicy:
            TableName: !Ref AsyncTransformTestResultsTable
        - S3ReadPolicy:
            BucketName: 
              !Sub "async-destination-${AWS::StackName}-${AWS::AccountId}"
      Events:
        FileUpload:
          Type: S3
          Properties:
            Bucket: !Ref DestinationBucket
            Events: s3:ObjectCreated:*
            Filter:
              S3Key:
                Rules:
                  - Name: suffix
                    Value: '.txt'


Outputs:

    SourceBucketName:
      Description: "Source bucket for asynchronous testing sample"
      Value: !Ref SourceBucket

    DestinationBucketName:
      Description: "Destination bucket for asynchronous testing sample"
      Value: !Ref DestinationBucket

    DestinationBucketListenerName:
      Condition: CreateTestResources
      Description: "Lambda Function to listen for test results"
      Value: !Ref DestinationBucketListener

    AsyncTransformTestResultsTable:
      Condition: CreateTestResources
      Description: "DynamoDB table to persist test results"
      Value: !Ref AsyncTransformTestResultsTable