add LangChain AI Handler

pr_agent/algo/ai_handlers/langchain_ai_handler.py

@@ -0,0 +1,45 @@
+from pr_agent.algo.ai_handlers.base_ai_handler import BaseAiHandler
+from langchain.chat_models import ChatOpenAI
+from langchain.prompts.chat import (
+    ChatPromptTemplate,
+    HumanMessagePromptTemplate,
+    SystemMessagePromptTemplate,
+)
+from langchain.schema import SystemMessage, HumanMessage
+
+
+from pr_agent.config_loader import get_settings
+from pr_agent.log import get_logger
+
+OPENAI_RETRIES = 5
+chat = ChatOpenAI(openai_api_key = get_settings().openai.key, model="gpt-4")
+
+class LangChainAIHandler(BaseAiHandler):
+    def __init__(self):
+        # Initialize OpenAIHandler specific attributes here
+        try:
+            super().__init__()            
+        
+        except AttributeError as e:
+            raise ValueError("OpenAI key is required") from e
+    @property
+    def deployment_id(self):
+        """
+        Returns the deployment ID for the OpenAI API.
+        """
+        return get_settings().get("OPENAI.DEPLOYMENT_ID", None)
+        
+    async def chat_completion(self, model: str, system: str, user: str, temperature: float = 0.2):
+        try:
+
+            messages=[SystemMessage(content=system), HumanMessage(content=user)]
+            
+            # get a chat completion from the formatted messages
+            resp = chat(messages)
+            get_logger().info("AI response: ", resp.content)
+            finish_reason="completed"
+            return resp.content, finish_reason
+        
+        except (Exception) as e:
+            get_logger().error("Unknown error during OpenAI inference: ", e)
+            raise e

pr_agent/algo/utils.py

@@ -11,6 +11,7 @@ import yaml
 from pr_agent.algo.ai_handlers.litellm_ai_handler import LiteLLMAiHandler
 from pr_agent.algo.ai_handlers.base_ai_handler import BaseAiHandler
 from pr_agent.algo.ai_handlers.openai_ai_handler import OpenAIHandler
+from pr_agent.algo.ai_handlers.langchain_ai_handler import LangChainAIHandler
 from starlette_context import context
 from pr_agent.config_loader import get_settings, global_settings
 from pr_agent.log import get_logger
@@ -309,4 +310,4 @@ def try_fix_yaml(review_text: str) -> dict:
     return data
 
 def get_ai_handler() -> BaseAiHandler:
-    return OpenAIHandler()
+    return LangChainAIHandler()