cloudformation_template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Parameters:
  BotName:
    Type: String
    Default: chatgpt-bot
  FunctionHandler:
    Type: String
    Default: 'com.anderb.chatbot.BotApplication::handleRequest'
  OpenAIApiKey:
    Type: String
    NoEcho: true
  AllowedUsers:
    Type: String
    Description: Comma separated whitelisted telegram user ids
  BotToken:
    Type: String
    NoEcho: true
    Description: 'Example: 1234567890:xxxxxxxxx'
  BotUsername:
    Type: String
    Description: Must start with @
  S3Bucket:
    Type: String
    Description: S3 bucket with function archive
  S3Key:
    Type: String
    Description: Function archive name

Resources:
  ChatHistoryTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub '${BotName}-history'
      AttributeDefinitions:
        - AttributeName: chat_id
          AttributeType: N
      KeySchema:
        - AttributeName: chat_id
          KeyType: HASH
      BillingMode: PAY_PER_REQUEST

  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      Policies:
        - PolicyName: ChatBotCloudWatchDynamoDBPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - logs:CreateLogGroup
                  - logs:CreateLogStream
                  - logs:PutLogEvents
                Resource: arn:aws:logs:*:*:*
              - Effect: Allow
                Action:
                  - dynamodb:PutItem
                  - dynamodb:GetItem
                Resource: !Sub 'arn:aws:dynamodb:${AWS::Region}:${AWS::AccountId}:table/${BotName}-history'

  ChatGPTBotFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: !Sub '${BotName}-function'
      Description: 'Lambda backend for Telegram Bot'
      Runtime: java11
      Handler: !Ref FunctionHandler
      Code:
        S3Bucket: !Ref S3Bucket
        S3Key: !Ref S3Key
      Role: !GetAtt LambdaExecutionRole.Arn
      Timeout: 300
      MemorySize: 512
      Environment:
        Variables:
          AI_MODEL: gpt-3.5-turbo
          OPENAI_API_KEY: !Ref OpenAIApiKey
          OPENAI_API_URL: https://api.openai.com/v1/chat/completions
          ALLOWED_USERS: !Ref AllowedUsers
          BOT_TOKEN: !Ref BotToken
          BOT_URL: !Sub 'https://${MyApi}.execute-api.${AWS::Region}.amazonaws.com/prod/${BotName}'
          BOT_USERNAME: !Ref BotUsername
          JAVA_TOOL_OPTIONS: -Dorg.slf4j.simpleLogger.defaultLogLevel=debug
          DYNAMO_TABLE_NAME: !Sub '${BotName}-history'
          HISTORY_LENGTH: 8
          SESSION_MAX_LIFETIME: 120
      Architectures:
        - arm64

  MyApi:
    Type: AWS::ApiGateway::RestApi
    Properties:
      Name: !Sub '${BotName}-api'
      Description: !Sub 'API Gateway for ${BotName}'
      EndpointConfiguration:
        Types:
          - REGIONAL

  MyFunctionResource:
    Type: AWS::ApiGateway::Resource
    Properties:
      RestApiId: !Ref MyApi
      ParentId: !GetAtt MyApi.RootResourceId
      PathPart: !Ref BotName

  MyFunctionMethod:
    Type: AWS::ApiGateway::Method
    Properties:
      RestApiId: !Ref MyApi
      ResourceId: !Ref MyFunctionResource
      HttpMethod: POST
      AuthorizationType: NONE
      Integration:
        Type: AWS
        IntegrationHttpMethod: POST
        Uri: !Sub 'arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ChatGPTBotFunction.Arn}/invocations'
        PassthroughBehavior: WHEN_NO_MATCH
        RequestParameters:
          integration.request.header.X-Amz-Invocation-Type: "'Event'"
        IntegrationResponses:
          - StatusCode: 200
            ResponseTemplates:
              application/json: ''
        ContentHandling: CONVERT_TO_TEXT
      MethodResponses:
        - StatusCode: 200

  ApiGatewayDeployment:
    Type: AWS::ApiGateway::Deployment
    DependsOn: MyFunctionMethod
    Properties:
      RestApiId: !Ref MyApi
      StageName: prod

  LambdaInvokePermission:
    Type: AWS::Lambda::Permission
    Properties:
      FunctionName: !Ref ChatGPTBotFunction
      Action: lambda:InvokeFunction
      Principal: apigateway.amazonaws.com
      SourceArn: !Sub 'arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${MyApi}/*/POST/${BotName}'

Outputs:
  TableNameOutput:
    Description: DynamoDB table name
    Value: !Sub '${BotName}-history'
  FunctionNameOutput:
    Description: Lambda Function name
    Value: !Sub '${BotName}-function'
  RestApiNameOutput:
    Description: ApiGateway RestApi name
    Value: !Sub '${BotName}-api'
  ApiEndpointUrl:
    Description: The URL of the API endpoint
    Value: !Sub 'https://${MyApi}.execute-api.${AWS::Region}.amazonaws.com/prod/${BotName}'