lambda-durable-human-approval-sam: Fix hardcoded API Gateway URL by using environment variable

Author: kakakakakku

lambda-durable-human-approval-sam/src/lambda_function.py

@@ -29,8 +29,7 @@ def lambda_handler(event, context: DurableContext):
     description = body.get('description', 'No description')
 
     # Get API Gateway URL from environment or construct it
-    region = os.environ.get('AWS_REGION', 'us-east-2')
-    api_base_url = f"https://w8a9tempjb.execute-api.{region}.amazonaws.com/prod"
+    api_base_url = os.environ['API_BASE_URL']
 
     print(f"Starting approval workflow for request: {request_id}")
     print(f"API Base URL: {api_base_url}")

lambda-durable-human-approval-sam/template.yaml

@@ -36,6 +36,7 @@ Resources:
   CallbackHandlerFunction:
     Type: AWS::Serverless::Function
     Properties:
+      FunctionName: !Sub '${AWS::StackName}-CallbackHandlerFunction'
       CodeUri: src/
       Handler: callback_handler.lambda_handler
       Runtime: python3.14
@@ -56,6 +57,7 @@ Resources:
   ApprovalFunction:
     Type: AWS::Serverless::Function
     Properties:
+      FunctionName: !Sub '${AWS::StackName}-ApprovalFunction'
       CodeUri: src/
       Handler: lambda_function.lambda_handler
       Runtime: python3.14
@@ -68,6 +70,7 @@ Resources:
         Variables:
           APPROVAL_TOPIC_ARN: !Ref ApprovalTopic
           CALLBACK_TABLE_NAME: !Ref CallbackTable
+          API_BASE_URL: !Sub 'https://${ApprovalApi}.execute-api.${AWS::Region}.amazonaws.com/prod'
       Policies:
         - SNSPublishMessagePolicy:
             TopicName: !GetAtt ApprovalTopic.TopicName
@@ -134,7 +137,7 @@ Resources:
               x-amazon-apigateway-integration:
                 type: aws
                 httpMethod: POST
-                uri: !Sub 'arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${ApprovalFunction.Arn}:live/invocations'
+                uri: !Sub 'arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${AWS::StackName}-ApprovalFunction:live/invocations'
                 requestParameters:
                   integration.request.header.X-Amz-Invocation-Type: "'Event'"
                 responses: