使用sam deploy部署API Gateway时遇No integration defined for method错误求助

以下是针对该问题的排查方向和解决方法：

• 检查OpenAPI文件的集成配置
  用OpenAPI定义API Gateway时，必须通过x-amazon-apigateway-integration扩展指定请求转发的目标Lambda函数。确保api.yaml中对应路径的method下包含该配置块，示例如下：

  paths:
    /your-endpoint:
      get:
        responses:
          '200':
            description: Success response
        x-amazon-apigateway-integration:
          type: aws_proxy
          uri: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${LambdaFunctionArn}/invocations
          httpMethod: POST
          credentials: arn:aws:iam::${AWS::AccountId}:role/YourApiGatewayExecutionRole
  

  注意type需设为aws_proxy（Lambda代理集成），httpMethod固定为POST，uri指向你的Lambda函数ARN，credentials是API Gateway调用Lambda所需的IAM角色ARN。

• 动态传递Lambda ARN到OpenAPI文件
  不要在api.yaml中硬编码Lambda ARN，而是在template.yaml中通过!Sub动态注入，避免环境不一致问题。示例：

  Resources:
    MyApi:
      Type: AWS::Serverless::Api
      Properties:
        StageName: prod
        DefinitionBody:
          !Sub
            - |
              openapi: 3.0.1
              info:
                title: My API
                version: 1.0.0
              paths:
                /your-endpoint:
                  get:
                    responses:
                      '200':
                        description: OK
                    x-amazon-apigateway-integration:
                      type: aws_proxy
                      uri: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${LambdaArn}/invocations
                      httpMethod: POST
                      credentials: !GetAtt ApiGatewayRole.Arn
            - LambdaArn: !GetAtt MyLambdaFunction.Arn
  

• 添加API Gateway调用Lambda的权限
  新增Lambda权限资源，允许API Gateway触发你的Lambda函数：

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

• 验证OpenAPI文件完整性
  确认api.yaml中定义的所有路径和method都配置了对应的集成块，不能仅定义路径和响应规则而遗漏集成配置。

内容的提问来源于stack exchange，提问作者Nilotpal