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aws(学习笔记第三十六课) apigw-http-api-lambda-dynamodb

• 使用api gateway中使用lambda+dynamodb

学习内容：

• 使用api gateway
• 使用lambda
• 使用dynamodb

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1. 整体架构

1.1 代码链接

• 代码链接（apigw-http-api-lambda-dynamodb-python-cdk）
• aws(学习笔记第十四课) 面向NoSQL DB的DynamoDB
  可以复习下以前的dynamodb的知识。

1.2 整体架构

• API gateway访问lambda函数
• lambda通过终端节点访问dynamodb

2. 代码解析

2.1 创建vpc

# VPCvpc = ec2.Vpc(self,"Ingress",cidr="10.1.0.0/16",subnet_configuration=[ec2.SubnetConfiguration(name="Private-Subnet", subnet_type=ec2.SubnetType.PRIVATE_ISOLATED,cidr_mask=24)],)

这里，只创建private subnet。

2.2 创建vpc的终端节点

通常，private subnet里面的lambda是没有办法访问dynamodb的，如果想访问。有两种方式：

• 一种是通过给public subnet里面设定NAT gateway。
• 另一种通过vpc endpoint，即vpc的终端节点。终端节点需要执行面向的service，这里是dynamodb。

 # Create VPC endpointdynamo_db_endpoint = ec2.GatewayVpcEndpoint(self,"DynamoDBVpce",service=ec2.GatewayVpcEndpointAwsService.DYNAMODB,vpc=vpc,)

2.3 对vpc的终端节点设定policy

# This allows to customize the endpoint policydynamo_db_endpoint.add_to_policy(iam.PolicyStatement(  # Restrict to listing and describing tablesprincipals=[iam.AnyPrincipal()],actions=[                "dynamodb:DescribeStream","dynamodb:DescribeTable","dynamodb:Get*","dynamodb:Query","dynamodb:Scan","dynamodb:CreateTable","dynamodb:Delete*","dynamodb:Update*","dynamodb:PutItem"],resources=["*"],))

这里设定通过该endpoint，任何resource都能够进行dynamodb相关的操作。

2.4 创建dynamodb的``table

        # Create DynamoDb Tabledemo_table = dynamodb_.Table(self,TABLE_NAME,partition_key=dynamodb_.Attribute(name="id", type=dynamodb_.AttributeType.STRING),)

2.5 创建lambda函数

        # Create the Lambda function to receive the requestapi_hanlder = lambda_.Function(self,"ApiHandler",function_name="apigw_handler",runtime=lambda_.Runtime.PYTHON_3_9,code=lambda_.Code.from_asset("lambda/apigw-handler"),handler="index.handler",vpc=vpc,vpc_subnets=ec2.SubnetSelection(subnet_type=ec2.SubnetType.PRIVATE_ISOLATED),memory_size=1024,timeout=Duration.minutes(5),)

2.6 lambda函数的代码（/lambda/apigw-handler/）

def handler(event, context):table = os.environ.get("TABLE_NAME")logging.info(f"## Loaded table name from environemt variable DDB_TABLE: {table}")if event["body"]:item = json.loads(event["body"])logging.info(f"## Received payload: {item}")year = str(item["year"])title = str(item["title"])id = str(item["id"])dynamodb_client.put_item(TableName=table,Item={"year": {"N": year}, "title": {"S": title}, "id": {"S": id}},)message = "Successfully inserted data!"return {"statusCode": 200,"headers": {"Content-Type": "application/json"},"body": json.dumps({"message": message}),}else:logging.info("## Received request without a payload")dynamodb_client.put_item(TableName=table,Item={"year": {"N": "2012"},"title": {"S": "The Amazing Spider-Man 2"},"id": {"S": str(uuid.uuid4())},},)message = "Successfully inserted data!"return {"statusCode": 200,"headers": {"Content-Type": "application/json"},"body": json.dumps({"message": message}),}

2.7 为dynamodb的table设定lambda函数的权限，以及通过env设定表名

        # grant permission to lambda to write to demo tabledemo_table.grant_write_data(api_hanlder)api_hanlder.add_environment("TABLE_NAME", demo_table.table_name)

2.8 创建api gateway，并设定handler为lambda函数

        # Create API Gatewayapigw_.LambdaRestApi(self,"Endpoint",handler=api_hanlder,)

3 执行整个架构

3.1 开始部署

cdk --require-approval never deploy

3.2 访问API gateway