Tạo hàm order_management Lambda

Trong bước này, chúng ta sẽ tạo một hàm order_management Lambda mới bằng cách sử dụng mẫu SAM.

Chuẩn bị

  1. Mở template.yaml trong mã nguồn bạn đã tải xuống trước đó.

    • Bình luận khối mã này.

      # BookApiDeployment:
#   Type: AWS::ApiGateway::Deployment
#   Properties:
#     RestApiId: !Ref BookApi
#   DependsOn:
#     - BookApiGet
#     - BookApiCreate
#     - BookApiDelete
#     - LoginApi
#     - RegisterApi
#     - ConfirmApi

BookApiStage:
  Type: AWS::ApiGateway::Stage
  Properties:
    RestApiId: !Ref BookApi
    StageName: !Ref stage
#     DeploymentId: !Ref BookApiDeployment

      CreateOrderManagementFunction

  2. Chạy các lệnh dưới đây.

    sam build
sam validate
sam deploy

    CreateOrderManagementFunction

Tạo hàm FcjOrderManagement

  1. Mở template.yaml trong mã nguồn bạn đã tải xuống trước đó.

    • Thêm các đoạn mã sau để tạo hàm FcjOrderManagement.

      FcjOrderManagementFunction:
  Type: AWS::Serverless::Function
  Properties:
    CodeUri: fcj-book-shop/order_management
    Handler: order_management.lambda_handler
    Runtime: python3.11
    FunctionName: order_management
    Environment:
      Variables:
        SQS_QUEUE_URL: !Ref checkoutQueueUrl
        ORDER_TABLE_NAME: !Ref orderTable
    Architectures:
      - x86_64
    Policies:
      - Statement:
          - Sid: VisualEditor0
            Effect: Allow
            Action:
              - dynamodb:Scan
              - dynamodb:Query
            Resource:
              - !Sub "arn:aws:dynamodb:${AWS::Region}:${AWS::AccountId}:table/${orderTable}"
          - Sid: VisualEditor1
            Effect: Allow
            Action:
              - sqs:*
            Resource:
              - !Sub "arn:aws:sqs:${AWS::Region}:${AWS::AccountId}:${checkoutQueueName}"

FcjOrderManagementApi:
  Type: AWS::ApiGateway::Method
  Properties:
    HttpMethod: GET
    RestApiId: !Ref BookApi
    ResourceId: !Ref FcjCheckoutOrderResource
    AuthorizationType: NONE
    Integration:
      Type: AWS_PROXY
      IntegrationHttpMethod: POST # For Lambda integrations, you must set the integration method to POST
      Uri: !Sub >-
        arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${FcjOrderManagementFunction.Arn}/invocations
    MethodResponses:
      - StatusCode: "200"
        ResponseParameters:
          method.response.header.Access-Control-Allow-Origin: true
          method.response.header.Access-Control-Allow-Methods: true
          method.response.header.Access-Control-Allow-Headers: true

FcjOrderManagementApiInvokePermission:
  Type: AWS::Lambda::Permission
  Properties:
    FunctionName: !Ref FcjOrderManagementFunction
    Action: lambda:InvokeFunction
    Principal: apigateway.amazonaws.com
    SourceAccount: !Ref "AWS::AccountId"

      CreateOrderManagementFunction

  2. Cấu trúc thư mục như sau.

    fcj-book-shop-sam-ws3
├── fcj-book-shop
│   ├── checkout_order
│   │   └── checkout_order.py
│   ├── order_management
│   │   └── order_management.py
│   ├── ...
│
└── template.yaml

    • Tạo thư mục order_management trong thư mục fcj-book-shop-sam-ws6/fcj-book-shop/.

    • Tạo tệp order_management.py và sao chép mã sau vào đó.

      import os
import json
import boto3

headers = {
    "Content-Type": "application/json",
    "Access-Control-Allow-Origin": "*",
    "Access-Control-Allow-Methods": "OPTIONS,POST,GET,DELETE",
    "Access-Control-Allow-Headers": "Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token"
}

dynamodb = boto3.resource('dynamodb')
sqs = boto3.client('sqs')

# Get value of the environment variables
table_name = os.getenv('ORDER_TABLE_NAME')
queue_url = os.getenv('SQS_QUEUE_URL')


def get_messages_from_sqs(messages):
    # Get the total number of messages in the queue
    response = sqs.get_queue_attributes(
        QueueUrl=queue_url,
        AttributeNames=['ApproximateNumberOfMessages']
    )
    total_messages = int(response['Attributes']['ApproximateNumberOfMessages'])

    while len(messages) < total_messages:
        # Receive messages from SQS queue
        received_message_res = sqs.receive_message(
            QueueUrl=queue_url,
            MaxNumberOfMessages=10,
            WaitTimeSeconds=20
        )

        if 'Messages' in received_message_res:
            for message in received_message_res['Messages']:
                messages.append({
                    "receiptHandle": message["ReceiptHandle"],
                    "books": json.loads(message["Body"])['books'],
                    "price": json.loads(message["Body"])['price'],
                    "status": "Unprocessed"
                })


def get_messages_from_dynamodb(messages):
    table = dynamodb.Table(table_name)

    try:
        res = table.scan()
        orders = res.get('Items', [])
        aggregated_orders = {}

        for order in orders:
            order_id = order['id']

            book = {
                'id': order['book_id'],
                'name': order['name'],
                'qty': order['qty'],
            }

            if order_id not in aggregated_orders:
                aggregated_orders[order_id] = {
                    'id': order_id,
                    'books': [book],
                    'price': order['price']
                }

            else:
                aggregated_orders[order_id]['books'].append(book)

        for order in aggregated_orders.values():
            messages.append({
                "receiptHandle": "",
                "books": order['books'],
                "price": order['price'],
                "status": "Processed"
            })

    except Exception as e:
        print(f"Error reading from DynamoDB: {e}")
        raise Exception(f"Error reading from DynamoDB: {e}")


def lambda_handler(event, context):
    messages = []

    # Get messages from sqs
    get_messages_from_sqs(messages)

    # Get Messages from DynamoDB
    get_messages_from_dynamodb(messages)

    return {
        'statusCode': 200,
        'body': json.dumps(messages),
        'headers': headers
    }

      CreateOrderManagementFunction

  3. Bỏ bình luận khối mã này.

    BookApiDeployment:
  Type: AWS::ApiGateway::Deployment
  Properties:
    RestApiId: !Ref BookApi
  DependsOn:
    - BookApiGet
    - BookApiCreate
    - BookApiDelete
    - LoginApi
    - RegisterApi
    - ConfirmApi
    - FcjCheckoutOrderApi
    - FcjOrderManagementApi

BookApiStage:
  Type: AWS::ApiGateway::Stage
  Properties:
    RestApiId: !Ref BookApi
    StageName: !Ref stage
    DeploymentId: !Ref BookApiDeployment

    CreateOrderManagementFunction

  4. Chạy các lệnh dưới đây.

    sam build
sam validate
sam deploy

    CreateOrderManagementFunction

Kiểm tra việc tạo

  1. Mở Amazon API Gateway console.

    • Nhấp vào fcj-serverless-api. CreateOrderManagementFunction
    • Nhấp vào Resources trên menu bên trái.
    • Kiểm tra /order vừa được tạo. CreateOrderManagementFunction

  2. Mở Amazon Lambda console.

    • Nhấp vào Functions trên menu bên trái.
    • Chọn hàm order_management. CreateOrderManagementFunction
    • Tại trang order_management, kiểm tra hàm vừa được tạo. CreateOrderManagementFunction