Fix issue #3609: Add URL validation for Ollama connections

[devin-ai-integration]

Fix issue #3609: Add URL validation for Ollama connections

Summary

Adds early URL validation specifically for Ollama connections to provide clear, actionable error messages when users specify invalid URLs like http://192.168.0.300:11434. Previously, users would get a cryptic "No route to host" error from litellm after the request failed.

Key Changes:

• Added _validate_base_url() method to validate URL format and IP addresses
• Extended _validate_call_params() to validate Ollama base_url and api_base parameters
• Added comprehensive test coverage for invalid IPs, malformed URLs, and valid URLs
• Only validates URLs for Ollama models to avoid affecting other LLM providers

Before: litellm.APIConnectionError: OllamaException - [Errno 65] No route to host
After: Invalid Ollama base_url: 'http://192.168.0.300:11434'. Please check that the URL format is correct and the IP address is valid. Example: 'http://localhost:11434' or 'http://192.168.1.100:11434'

Review & Testing Checklist for Human

⚠️ 3 critical items to verify:

• Test the reported bug scenario: Create an LLM with model="ollama/llama3.1" and base_url="http://192.168.0.300:11434" and verify it shows the new clear error message instead of the cryptic litellm error
• Test edge cases in validation logic: Try various URL formats (IPv6, internationalized domains, unusual ports) and IP addresses (edge cases like 192.168.0.1, 192.168.1.255) to ensure the validation logic handles them correctly
• Verify no regressions: Test existing working Ollama configurations (localhost, valid private IPs, domain names) to ensure they still work without throwing validation errors

Notes

• The IP detection uses a heuristic (all(part.isdigit() for part in hostname.split('.')) and len(hostname.split('.')) == 4) which may have edge cases worth testing
• Model detection uses simple string matching ("ollama" in self.model.lower()) - verify this doesn't accidentally affect other providers
• Non-Ollama models should completely skip this validation even with invalid URLs

Requested by: João ([email protected]) via Slack
Devin session: https://app.devin.ai/sessions/c740336126bb41529cf6799c59db01a7

[devin-ai-integration]

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