使用Serverless.yaml创建Lex Bot时无法添加Bedrock QnA Intent的解决

• IAM角色权限不足：当前配置的Lex Bot角色仅包含日志操作权限，没有允许调用AWS Bedrock模型的权限，导致Lex无法访问Bedrock服务处理QnA请求。
• Intent类型配置错误：Bedrock QnA属于生成式Intent，不能按照普通自定义Intent或内置Intent的方式配置，必须明确指定IntentType: Generative，并配置关联Bedrock模型的参数。
• 区域模型兼容性问题：需确认使用的AWS区域（eu-west-2）支持目标Bedrock模型，比如Anthropic Claude 3系列在该区域是可用的。

1. 更新IAM角色权限 #

在LexBotRole的PolicyDocument中添加Bedrock访问权限，允许调用指定的Bedrock模型：

Policies:
  - PolicyName: LexBotPolicy
    PolicyDocument:
      Version: "2012-10-17"
      Statement:
        - Effect: Allow
          Action:
            - logs:CreateLogGroup
            - logs:CreateLogStream
            - logs:PutLogEvents
          Resource: "arn:aws:logs:*:*:*"
        - Effect: Allow
          Action:
            - bedrock:InvokeModel
          Resource: "arn:aws:bedrock:eu-west-2::model/anthropic.claude-3-haiku-20240307-v1:0" # 根据需求替换模型ARN

2. 添加Bedrock QnA生成式Intent #

在BotLocales的Intents列表中添加生成式QnA Intent，配置IntentType和GenerativeIntentSetting：

# Lex Bot Definition
MyLexBot:
  Type: AWS::Lex::Bot
  Properties:
    Name: MySampleBot
    RoleArn: !GetAtt LexBotRole.Arn
    DataPrivacy:
      ChildDirected: false
    IdleSessionTTLInSeconds: 300
    BotLocales:
      - LocaleId: en_US
        NluConfidenceThreshold: 0.40
        Intents:
          - Name: GreetingIntent
            SampleUtterances:
              - Utterance: Hello
              - Utterance: Hi
            IntentClosingSetting:
              ClosingResponse:
                MessageGroupsList:
                  - Message:
                      PlainTextMessage:
                        Value: "Hello! How can I help you today?"
          - Name: FallbackIntent
            ParentIntentSignature: AMAZON.FallbackIntent
            IntentClosingSetting:
              ClosingResponse:
                MessageGroupsList:
                  - Message:
                      PlainTextMessage:
                        Value: "I'm sorry, I didn't understand that. Can you please rephrase?"
          # 添加Bedrock QnA生成式Intent
          - Name: BedrockQnAIntent
            IntentType: Generative
            GenerativeIntentSetting:
              PromptSpecification:
                PromptTemplates:
                  - PromptTemplate: |
                      Answer the user's question clearly and concisely.
                      User question: {inputTranscript}
              GenerationSetting:
                GenerationConfig:
                  MaxTokenCount: 1000
                  Temperature: 0.7
                  TopP: 0.9
              BedrockModelSetting:
                ModelArn: "arn:aws:bedrock:eu-west-2::model/anthropic.claude-3-haiku-20240307-v1:0" # 与IAM权限中的模型ARN一致
            SampleUtterances:
              - Utterance: "How do I reset my password?"
              - Utterance: "What's your return policy?"
              - Utterance: "Tell me about your services"

关键配置说明 #

• IntentType: 必须设置为Generative，标识这是一个生成式Intent，关联Bedrock模型。
• PromptSpecification: 定义引导Bedrock模型生成回答的提示模板，{inputTranscript}会替换为用户的实际提问内容。
• BedrockModelSetting: 指定要使用的Bedrock模型ARN，需确保该模型在eu-west-2区域可用，且IAM角色拥有该模型的调用权限。
• SampleUtterances: 提供示例提问，帮助Lex识别用户的QnA类请求并路由到该Intent。

内容的提问来源于stack exchange，提问作者Thomas Joseph