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lambda-durable-human-approval-sam: Fix hardcoded API Gateway URL by using environment variable #2921

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lambda-durable-human-approval-sam: Fix hardcoded API Gateway URL by using environment variable #2921

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lambda-durable-human-approval-sam: Fix hardcoded API Gateway URL by u…
kakakakakku Feb 1, 2026
9426048
lambda-durable-human-approval-sam: Fix README for wrong pattern name
kakakakakku Jan 31, 2026
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10 changes: 5 additions & 5 deletions lambda-durable-human-approval-sam/README.md
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Expand Up @@ -4,7 +4,7 @@ This pattern demonstrates a human-in-the-loop approval workflow using AWS Lambda

**Important:** Please check the [AWS documentation](https://docs.aws.amazon.com/lambda/latest/dg/durable-functions.html) for regions currently supported by AWS Lambda durable functions.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/lambda-durable-hitl-approval-sam
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@kakakakakku kakakakakku Feb 1, 2026

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note: It's wrong url

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/lambda-durable-human-approval-sam

## Architecture

Expand Down Expand Up @@ -44,7 +44,7 @@ The pattern uses Lambda durable functions to implement a cost-effective approval

1. Navigate to the pattern directory:
```bash
cd lambda-durable-hitl-approval-sam
cd lambda-durable-human-approval-sam
```

2. Build the SAM application:
Expand Down Expand Up @@ -197,14 +197,14 @@ sam deploy --parameter-overrides ApproverEmail=new-email@example.com

Monitor the durable function:
```bash
aws logs tail /aws/lambda/lambda-durable-hitl-approval-ApprovalFunction-XXXXX \
aws logs tail /aws/lambda/lambda-durable-human-approval-ApprovalFunction \
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@kakakakakku kakakakakku Feb 1, 2026

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note: Update CloudWatch Logs log group name because I set FunctionName in SAM template

--region us-east-2 \
--follow
```

Monitor the callback handler:
```bash
aws logs tail /aws/lambda/lambda-durable-hitl-approv-CallbackHandlerFunction-XXXXX \
aws logs tail /aws/lambda/lambda-durable-human-approval-CallbackHandlerFunction \
--region us-east-2 \
--follow
```
Expand All @@ -214,7 +214,7 @@ aws logs tail /aws/lambda/lambda-durable-hitl-approv-CallbackHandlerFunction-XXX
## Cleanup

```bash
sam delete --stack-name lambda-durable-hitl-approval --region us-east-2
sam delete --stack-name lambda-durable-human-approval --region us-east-2
```


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3 changes: 1 addition & 2 deletions lambda-durable-human-approval-sam/src/lambda_function.py
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Expand Up @@ -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"
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@kakakakakku kakakakakku Feb 1, 2026

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note: Here is hardcoded API Gateway URL

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}")
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5 changes: 4 additions & 1 deletion lambda-durable-human-approval-sam/template.yaml
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Expand Up @@ -36,6 +36,7 @@ Resources:
CallbackHandlerFunction:
Type: AWS::Serverless::Function
Properties:
FunctionName: !Sub '${AWS::StackName}-CallbackHandlerFunction'
CodeUri: src/
Handler: callback_handler.lambda_handler
Runtime: python3.14
Expand All @@ -56,6 +57,7 @@ Resources:
ApprovalFunction:
Type: AWS::Serverless::Function
Properties:
FunctionName: !Sub '${AWS::StackName}-ApprovalFunction'
CodeUri: src/
Handler: lambda_function.lambda_handler
Runtime: python3.14
Expand All @@ -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'
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@kakakakakku kakakakakku Feb 1, 2026

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note: To pass the API_BASE_URL environment variable to the Lambda function, we needed to resolve a circular dependency between the Lambda function and API Gateway. To break this cycle, we explicitly set the Lambda FunctionName and manually constructed the ARN in the API Gateway integration URI. This reduces the dependency to a one-way reference from the Lambda function to API Gateway, resolving the circular dependency😀

Policies:
- SNSPublishMessagePolicy:
TopicName: !GetAtt ApprovalTopic.TopicName
Expand Down Expand Up @@ -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:
Expand Down