Refactor LangChain AI Handler for Async and Performance

- Add async LLM object creation and invocation
- Branch parameter handling by LLM type
- Enhance error logging and handler consistency
- Add performance and concurrency test code

tests/unittest/test_langchain.py

@@ -0,0 +1,89 @@
+import asyncio
+import os
+import time
+from pr_agent.algo.ai_handlers.langchain_ai_handler import LangChainOpenAIHandler
+from pr_agent.config_loader import get_settings
+
+def check_settings():
+    print('Checking settings...')
+    settings = get_settings()
+    
+    # Check OpenAI settings
+    if not hasattr(settings, 'openai'):
+        print('OpenAI settings not found')
+        return False
+    
+    if not hasattr(settings.openai, 'key'):
+        print('OpenAI API key not found')
+        return False
+    
+    print('OpenAI API key found')
+    return True
+
+async def measure_performance(handler, num_requests=3):
+    print(f'\nRunning performance test with {num_requests} requests...')
+    start_time = time.time()
+    
+    # Create multiple requests
+    tasks = [
+        handler.chat_completion(
+            model='gpt-3.5-turbo',
+            system='You are a helpful assistant',
+            user=f'Test message {i}',
+            temperature=0.2
+        ) for i in range(num_requests)
+    ]
+    
+    # Execute requests concurrently
+    responses = await asyncio.gather(*tasks)
+    
+    end_time = time.time()
+    total_time = end_time - start_time
+    avg_time = total_time / num_requests
+    
+    print(f'Performance results:')
+    print(f'Total time: {total_time:.2f} seconds')
+    print(f'Average time per request: {avg_time:.2f} seconds')
+    print(f'Requests per second: {num_requests/total_time:.2f}')
+    
+    return responses
+
+async def test():
+    print('Starting test...')
+    
+    # Check settings first
+    if not check_settings():
+        print('Please set up your environment variables or configuration file')
+        print('Required: OPENAI_API_KEY')
+        return
+    
+    try:
+        handler = LangChainOpenAIHandler()
+        print('Handler created')
+        
+        # Basic functionality test
+        response = await handler.chat_completion(
+            model='gpt-3.5-turbo',
+            system='You are a helpful assistant',
+            user='Hello',
+            temperature=0.2,
+            img_path='test.jpg'
+        )
+        print('Response:', response)
+        
+        # Performance test
+        await measure_performance(handler)
+        
+    except Exception as e:
+        print('Error:', str(e))
+        print('Error type:', type(e))
+        print('Error details:', e.__dict__ if hasattr(e, '__dict__') else 'No additional details')
+
+if __name__ == '__main__':
+    # Print environment variables (without showing the actual key)
+    print('Environment variables:')
+    print('OPENAI_API_KEY:', 'Set' if os.getenv('OPENAI_API_KEY') else 'Not set')
+    print('OPENAI_API_TYPE:', os.getenv('OPENAI_API_TYPE', 'Not set'))
+    print('OPENAI_API_BASE:', os.getenv('OPENAI_API_BASE', 'Not set'))
+    
+    asyncio.run(test())