Azure Function

An Azure Function that processes debit transactions. This function takes a transaction ID and transaction data as input and calls the E-check Debit API.

Features

• Async Processing: Built with async/await for optimal performance
• Error Handling: Comprehensive error handling with detailed logging
• Request Tracking: Each request gets a unique request ID for tracking
• Timeout Management: Configurable timeouts for external API calls
• Environment Configuration: Uses environment variables for configuration

Setup

Prerequisites

• Python 3.8 or higher

• Azure Functions Core Tools

  • ubuntu

    1. curl https://packages.microsoft.com/keys/microsoft.asc | gpg --dearmor > microsoft.gpg

    2. sudo mv microsoft.gpg /etc/apt/trusted.gpg.d/microsoft.gpg

    3. sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-ubuntu-$(lsb_release -cs)-prod $(lsb_release -cs) main" > /etc/apt/sources.list.d/dotnetdev.list'

    4. apt-get update

    5. apt-get install azure-functions-core-tools-4

    6. curl http://localhost:7071/api/health

• Azure subscription (for deployment)

Local Development

1. Install dependencies:

   chmod +x setup.sh
   ./setup.sh
   
   source venv/bin/activate

2. Configure environment variables: Copy .env.template to .env and update the values:

   cp .env.template .env

   Edit .env with your actual API credentials:

   _BASE_URL=https://your-actual--url.com
   _AUTH_TOKEN=your-actual-auth-token
   

3. Run locally:

   func start

API Usage

Endpoint

• Method: POST
• Path: /api/debit
• Authentication: Function key required

Request Body

{
  "transaction_id": "TXN123456"
}

Response

Success Response (200)

{
  "success": true,
  "status_code": 200,
  "response_data": " API response data",
  "transaction_id": "TXN123456",
  "request_id": "uuid-here",
  "processing_time_ms": 1250.5
}

Error Response (4xx/5xx)

{
  "success": false,
  "status_code": 400,
  "error_message": "Error description",
  "transaction_id": "TXN123456",
  "request_id": "uuid-here",
  "processing_time_ms": 150.2
}

Deployment

Deploy to Azure from system

1. Install Azure CLI:

• curl -sL https://aka.ms/InstallAzureCLIDeb | sudo bash
• chmod +x deployment.sh
• ./deployment.sh
• Create a Storage Account from the Portal
• ./deployment.sh

2. Add environment variables: Portal > Function App > Settings > Environment Variables

3. Validate variables using this command: az functionapp config appsettings list --name payliance-function-app-1756466897 --resource-group payliance-rg --output table

4. func azure functionapp publish payliance-poc --python

Default Values

The function uses the following default values:

• Routing Number: 121000358
• Account Number: 5428610017522
• SEC Code: POS (if not provided)
• Account Type: Personal Checking
• Request Timeout: 30 seconds
• Connection Timeout: 10 seconds

Logging

The function provides comprehensive logging including:

• Request processing start/end
• API call details
• Error conditions
• Processing time metrics
• Request IDs for correlation

Logs are available in:

• Local development: Console output
• Azure: Application Insights and Function App logs

Error Handling

The function handles various error scenarios:

• Missing required fields: Returns 400 with descriptive error
• API timeouts: Returns 408 with timeout message
• HTTP errors: Returns appropriate status code with error details
• Network errors: Returns 500 with connection error details
• Unexpected errors: Returns 500 with generic error message

Testing

Local Testing with curl

curl -X POST "http://localhost:7071/api/debit" \
  -H "Content-Type: application/json" \
  -d '{
    "transaction_id": "TEST123"
  }'

Security Considerations

• Store sensitive configuration (API tokens) in Azure Key Vault for production
• Use managed identity for Azure resource access
• Enable authentication/authorization on the Function App
• Implement IP restrictions if needed
• Monitor and alert on function executions

Troubleshooting

Common Issues

1. Import errors: Ensure all dependencies are in requirements.txt
2. Authentication errors: Verify _AUTH_TOKEN is correct
3. Connection errors: Check _BASE_URL and network connectivity
4. Timeout errors: Adjust timeout values if needed

Debug Logging

Enable verbose logging by setting log level in host.json or through environment variables.

Updating Service bus settings

az servicebus queue update --name transactions --namespace-name transactions-payliance --resource-group payliance-rg --max-delivery-count 5 --lock-duration PT5M

Testing service bus with Azure Function

./setup_local_testing.sh python3 test_servicebus_local.py --send-message --transaction-id "10525241839999953614" ./cleanup_local_testing.sh