template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: LearnIA Chat Assistant Lambda

Parameters:
  Environment:
    Type: String
    Default: dev
  
  AtlasUri:
    Type: String
    NoEcho: true
  
  PostgresHost:
    Type: String
  
  PostgresPassword:
    Type: String
    NoEcho: true
  
  CorsAllowOrigin:
    Type: String
    Default: 'https://www.learn-ia.app'

  BedrockModelArn:
    Type: String
    Description: ARN del inference profile de Bedrock a utilizar
    Default: arn:aws:bedrock:us-west-2:974724840334:inference-profile/us.amazon.nova-pro-v1:0

Globals:
  Api:
    Cors:
      AllowOrigin: !Sub "'${CorsAllowOrigin}'"
      AllowMethods: "'GET,POST,DELETE,OPTIONS'"
      AllowHeaders: "'Content-Type,Authorization,X-User-Id'"

Resources:
  ChatSessionsTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub 'learnia-chat-sessions-${Environment}'
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - AttributeName: session_id
          AttributeType: S
        - AttributeName: timestamp
          AttributeType: N
        - AttributeName: user_id
          AttributeType: S
        - AttributeName: learning_path_id
          AttributeType: S
      KeySchema:
        - AttributeName: session_id
          KeyType: HASH
        - AttributeName: timestamp
          KeyType: RANGE
      TimeToLiveSpecification:
        Enabled: true
        AttributeName: ttl
      GlobalSecondaryIndexes:
        - IndexName: UserPathIndex
          KeySchema:
            - AttributeName: user_id
              KeyType: HASH
            - AttributeName: learning_path_id
              KeyType: RANGE
          Projection:
            ProjectionType: ALL
      Tags:
        - Key: Project
          Value: LearnIA
        - Key: Environment
          Value: !Ref Environment

  ChatAssistantFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub learnia-chat-assistant-${Environment}
      Runtime: python3.12
      Handler: chat_handler.lambda_handler
      CodeUri: src/
      Timeout: 120
      MemorySize: 1024
      Layers:
        - !Ref CertificatesLayer
      Environment:
        Variables:
          # DynamoDB
          CHAT_SESSIONS_TABLE: !Ref ChatSessionsTable
          SESSION_TTL_DAYS: 30
          MAX_HISTORY_MESSAGES: 10
          # MongoDB
          ATLAS_URI: !Ref AtlasUri
          DATABASE_NAME: learnia_db
          COLLECTION_NAME: courses
          # PostgreSQL
          POSTGRES_HOST: !Ref PostgresHost
          POSTGRES_PORT: 5432
          POSTGRES_DB: postgres
          POSTGRES_USER: postgres
          POSTGRES_PASSWORD: !Ref PostgresPassword
          DB_SSL: "true"
          DB_CA_PATH: /opt/certs/rds-us-east-2-bundle.pem
          # Bedrock
          BEDROCK_REGION: us-west-2
          BEDROCK_MODEL_ID: !Ref BedrockModelArn
          BEDROCK_TEMPERATURE: 0.7
          BEDROCK_MAX_TOKENS: 2048
          CORS_ALLOW_ORIGIN: !Ref CorsAllowOrigin
      Policies:
        - AWSLambdaBasicExecutionRole
        - DynamoDBCrudPolicy:
            TableName: !Ref ChatSessionsTable
        - Statement:
            - Effect: Allow
              Action:
                - dynamodb:Query
              Resource: !Sub '${ChatSessionsTable.Arn}/index/*'
            - Effect: Allow
              Action:
                - bedrock:InvokeModel
              Resource:
                - arn:aws:bedrock:us-west-2::foundation-model/us.amazon.nova-pro-v1:0
                - !Ref BedrockModelArn
            - Effect: Allow
              Action:
                - cloudwatch:PutMetricData
              Resource: '*'
      Events:
        SendMessage:
          Type: Api
          Properties:
            Path: /chat/message
            Method: POST
            RestApiId: !Ref ChatAssistantApi
        GetHistory:
          Type: Api
          Properties:
            Path: /chat/history/{session_id}
            Method: GET
            RestApiId: !Ref ChatAssistantApi
        GetSessions:
          Type: Api
          Properties:
            Path: /chat/sessions
            Method: GET
            RestApiId: !Ref ChatAssistantApi
        DeleteSession:
          Type: Api
          Properties:
            Path: /chat/session/{session_id}
            Method: DELETE
            RestApiId: !Ref ChatAssistantApi

  ChatAssistantApi:
    Type: AWS::Serverless::Api
    Properties:
      StageName: Prod
      Cors:
        AllowOrigin: !Sub "'${CorsAllowOrigin}'"
        AllowMethods: "'GET,POST,DELETE,OPTIONS'"
        AllowHeaders: "'Content-Type,Authorization,X-User-Id'"

  CertificatesLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: !Sub learnia-rds-ca-chat-${Environment}
      Description: RDS CA bundle for SSL connections
      ContentUri: layer-certs/certs/
      CompatibleRuntimes:
        - python3.12

Outputs:
  ChatAssistantApiUrl:
    Description: Chat Assistant API endpoint
    Value: !Sub 'https://${ChatAssistantApi}.execute-api.${AWS::Region}.amazonaws.com/Prod'
  
  ChatAssistantFunctionArn:
    Description: Lambda Function ARN
    Value: !GetAtt ChatAssistantFunction.Arn
  
  ChatSessionsTableName:
    Description: DynamoDB table name
    Value: !Ref ChatSessionsTable