Create delete_order Lambda function

In this step, we will create a new delete_order Lambda function using a SAM template.

Preparation

1. Open template.yaml in the source code you downloaded before.

   • Comment this code block.

     # BookApiDeployment:
     #   Type: AWS::ApiGateway::Deployment
     #   Properties:
     #     RestApiId: !Ref BookApi
     #   DependsOn:
     #     - BookApiGet
     #     - BookApiCreate
     #     - BookApiDelete
     #     - LoginApi
     #     - RegisterApi
     #     - ConfirmApi
     #     - FCAJCheckoutOrderApi
     #     - FCAJOrderManagementApi
     #     - FCAJHandleOrderApi
     
     BookApiStage:
       Type: AWS::ApiGateway::Stage
       Properties:
         RestApiId: !Ref BookApi
         StageName: !Ref stage
     #     DeploymentId: !Ref BookApiDeployment
     

     

2. Run the below commands.

   sam validate
   sam build
   

   

3. Deploy the updated stack.

   sam deploy
   

   

4. Wait for the deployment to complete.

   

Create FCAJDeleteOrder function

1. Open template.yaml in the source code you downloaded before.

   • Add the following scripts below to create FCAJDeleteOrder function.

     FCAJDeleteOrderFunction:
       Type: AWS::Serverless::Function
       Properties:
         CodeUri: fcaj-book-shop/delete_order
         Handler: delete_order.lambda_handler
         Runtime: python3.13
         FunctionName: delete_order
         Environment:
           Variables:
             SQS_QUEUE_URL: !Ref checkoutQueueUrl
         Architectures:
           - x86_64
         Policies:
           - Statement:
               - Sid: VisualEditor0
                 Effect: Allow
                 Action:
                   - sqs:*
                 Resource:
                   - !Sub "arn:aws:sqs:${AWS::Region}:${AWS::AccountId}:${checkoutQueueName}"
     

     

     FCAJDeleteOrderApi:
       Type: AWS::ApiGateway::Method
       Properties:
         HttpMethod: DELETE
         RestApiId: !Ref BookApi
         ResourceId: !Ref FCAJCheckoutOrderResource
         AuthorizationType: NONE
         Integration:
           Type: AWS_PROXY
           IntegrationHttpMethod: POST # For Lambda integrations, you must set the integration method to POST
           Uri: !Sub >-
             arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${FCAJDeleteOrderFunction.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
     
     FCAJDeleteOrderApiInvokePermission:
       Type: AWS::Lambda::Permission
       Properties:
         FunctionName: !Ref FCAJDeleteOrderFunction
         Action: lambda:InvokeFunction
         Principal: apigateway.amazonaws.com
         SourceAccount: !Ref "AWS::AccountId"
     

     

2. The directory structure is as follows.

   fcaj-book-shop
   ├── fcaj-book-shop
   │   ├── checkout_order
   │   │   └── checkout_order.py
   │   ├── order_management
   │   │   └── order_management.py
   │   ├── handle_order
   │   │   └── handle_order.py
   │   ├── delete_order
   │   │   └── delete_order.py
   │   ├── ...
   │
   └── template.yaml
   

   • Create delete_order folder in fcaj-book-shop/fcaj-book-shop/ folder.

   • Create delete_order.py file and copy the following code to it.

     import json
     import boto3
     import os
     
     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"
     }
     
     sqs = boto3.client('sqs')
     
     # Get value of the environment variables
     queue_url = os.getenv('SQS_QUEUE_URL')
     
     
     def lambda_handler(event, context):
         order = json.loads(event['body'])
     
         try:
             if 'receiptHandle' in order and order['receiptHandle']:
                 sqs.delete_message(
                     QueueUrl=queue_url,
                     ReceiptHandle=order['receiptHandle']
                 )
     
             else:
                 raise Exception("No receiptHandle provided")
     
         except Exception as e:
             print(f"Error deleting order: {e}")
             raise Exception(f"Error deleting order: {e}")
     
         return {
             'statusCode': 200,
             'headers': headers,
             'body': json.dumps('Order deleted successfully')
         }
     

     

3. Uncomment this code block.

   BookApiDeployment:
     Type: AWS::ApiGateway::Deployment
     Properties:
       RestApiId: !Ref BookApi
     DependsOn:
       - BookApiGet
       - BookApiCreate
       - BookApiDelete
       - LoginApi
       - RegisterApi
       - ConfirmApi
       - FCAJCheckoutOrderApi
       - FCAJOrderManagementApi
       - FCAJHandleOrderApi
       - FCAJDeleteOrderApi
   
   BookApiStage:
     Type: AWS::ApiGateway::Stage
     Properties:
       RestApiId: !Ref BookApi
       StageName: !Ref stage
       DeploymentId: !Ref BookApiDeployment
   

   

4. Run the below commands.

   sam validate
   sam build
   

   

5. Deploy the updated stack.

   sam deploy
   

   

6. Wait for the deployment to complete.

   

Check the creation

1. Open Amazon API Gateway console.

   • Click fcaj-serverless-api.
   • Click Resources on the left menu.
   • Check /order resource with DELETE, GET, OPTIONS, POST methods.

2. Open Amazon Lambda console.

   • Click Functions on the left menu.
   • Choose delete_order function.
   • At delete_order page, check the function that just created.