Add Azure Functions backend with OpenAI integration for chatbot

[Copilot]

Implements Task 1.4.1: HTTP-triggered Azure Function to handle chatbot queries via Azure OpenAI.

Implementation

• Function endpoint: POST /api/chat accepts user messages and optional conversation history, returns AI responses
• OpenAI integration: Azure OpenAI client with environment-based credentials (AZURE_OPENAI_API_KEY, AZURE_OPENAI_ENDPOINT)
• System prompt: AlpineBot persona specialized in Swiss information
• Input validation: JSON parsing, message presence, conversation history structure validation with 400 responses
• Error handling: Configuration errors, OpenAI API failures, empty response handling with appropriate status codes

API Contract

# Request
{
  "message": "What are the main cities in Switzerland?",
  "conversation_history": [  # Optional
    {"role": "user", "content": "Tell me about Switzerland"},
    {"role": "assistant", "content": "Switzerland is..."}
  ]
}

# Response
{
  "response": "The main cities include Zurich, Geneva...",
  "status": "success"
}

Dependencies

• azure-functions==1.24.0 - Function runtime
• openai==2.8.1 - Azure OpenAI SDK

Pinned versions for reproducible builds. Zero vulnerabilities (verified via gh-advisory-database and CodeQL).

Testing

10 unit tests covering:

• Missing/malformed inputs (JSON, message, conversation history)
• Configuration validation (missing credentials)
• OpenAI error scenarios (API errors, empty responses)
• Successful chat flow with/without history

All tests pass with mocked OpenAI client.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• cdn.functions.azure.com
  • Triggering command: /usr/bin/func func start (dns block)
• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Task 1.4.1: Create an Azure Function for the chatbot backend.</issue_title>
<issue_description>Task 1.4.1: Create an Azure Function for the chatbot backend.
The goal is to successfully and securely connect the chatbot to OpenAI to receive user's queries, and send the response back.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Task 1.4.1: Create an Azure Function for the chatbot backend. #72

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[fpittelo]

ok