如何通过AWS CDK构建含API网关与Lambda的AWS Amplify后端

核心原因 #

你直接通过CDK创建的Lambda和API Gateway属于独立AWS资源，未纳入Amplify的后端管理体系，因此Amplify控制台不会自动识别展示这些资源，前端aws-amplify库也无法自动关联。要实现关联，需通过Amplify专用CloudFormation资源或CDK构造将资源绑定到Amplify App。

方案1：通过Amplify CloudFormation资源关联（适配现有CDK代码） #

在现有代码基础上，添加Amplify后端环境、后端函数和后端API的CloudFormation资源，将已创建的Lambda和API Gateway绑定到Amplify App：

class AmplifyInfraStack(Stack):
    def __init__(self, scope: Construct, construct_id: str, **kwargs) -> None:
        super().__init__(scope, construct_id, **kwargs)

        # 创建Amplify App
        amplify_app = amplify.CfnApp(self, "MyApp", name='MyAppName')

        # 创建Lambda函数
        lambda_function = lambda_.Function(
            self, 
            'MyFunction', 
            code=lambda_.InlineCode(inline_code),
            handler='index.lambda_handler', 
            runtime=lambda_.Runtime.PYTHON_3_9
        )

        # 创建API Gateway
        api = apiGateway.LambdaRestApi(self, 'MyAPI', handler=lambda_function)

        # 创建Amplify后端环境（关联后端资源的基础）
        backend_env = amplify.CfnBackendEnvironment(self, "MyBackendEnv",
            app_id=amplify_app.attr_app_id,
            environment_name="prod",
            stack_name="AmplifyBackendProdStack"
        )

        # 将Lambda关联为Amplify后端函数，让控制台识别
        amplify_backend_function = amplify.CfnBackendFunction(self, "AmplifyMyFunction",
            app_id=amplify_app.attr_app_id,
            environment_name=backend_env.environment_name,
            function_name="MyFunction",
            lambda_function_config=amplify.CfnBackendFunction.LambdaFunctionConfigProperty(
                lambda_arn=lambda_function.function_arn,
                runtime="PYTHON_3_9"
            )
        )

        # 将API Gateway关联为Amplify后端API，让控制台识别
        amplify_backend_api = amplify.CfnBackendAPI(self, "AmplifyMyAPI",
            app_id=amplify_app.attr_app_id,
            environment_name=backend_env.environment_name,
            api_name="MyAPI",
            backend_api_config=amplify.CfnBackendAPI.BackendAPIConfigProperty(
                rest_api_config=amplify.CfnBackendAPI.RestAPIConfigProperty(
                    endpoint=api.url,
                    authorization_type="NONE"  # 根据需求调整认证类型，如API_KEY、AWS_IAM等
                )
            )
        )

关键说明 #

• CfnBackendEnvironment：为Amplify App创建后端环境，是关联后端资源的基础载体
• CfnBackendFunction：将已有Lambda的ARN绑定到Amplify后端体系，使控制台识别为Amplify托管函数
• CfnBackendAPI：将API Gateway的URL和配置绑定到Amplify后端，控制台会展示该API条目

方案2：配置前端aws-amplify对接外部资源 #

若无需在Amplify控制台展示资源，仅需前端能调用API，可通过Amplify App环境变量注入API信息，再在前端手动配置：

1. 在CDK中为Amplify App添加环境变量 #

amplify_app = amplify.CfnApp(self, "MyApp", 
    name='MyAppName',
    environment_variables={
        "API_URL": api.url,
        "AWS_REGION": self.region
    }
)

2. 前端配置aws-amplify #

在前端代码中手动导入API配置：

import { Amplify, API } from 'aws-amplify';

Amplify.configure({
  API: {
    endpoints: [
      {
        name: "MyAPI",
        endpoint: process.env.REACT_APP_API_URL, // 对应Amplify环境变量
        region: process.env.REACT_APP_AWS_REGION
      }
    ]
  }
});

// API调用示例
API.get("MyAPI", "/your-path").then(response => {
  console.log(response);
});

注意事项 #

• 方案1需确保Lambda和API Gateway的权限配置正确，可通过CDK为Amplify执行角色添加对应资源的调用权限
• 认证类型需根据实际场景调整，如使用AWS_IAM认证时，前端需配置IAM身份验证逻辑，确保用户具备API和Lambda的调用权限

内容的提问来源于stack exchange，提问作者Fin M.