fix: langfuse talk to model (#3535)

# Description

Please include a summary of the changes and the related issue. Please
also include relevant motivation and context.

## Checklist before requesting a review

Please delete options that are not relevant.

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented hard-to-understand areas
- [ ] I have ideally added tests that prove my fix is effective or that
my feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged

## Screenshots (if appropriate):

---------

Co-authored-by: Stan Girard <[email protected]>

core/quivr_core/rag/quivr_rag.py

@@ -12,9 +12,9 @@
 from langchain_core.runnables import RunnableLambda, RunnablePassthrough
 from langchain_core.vectorstores import VectorStore
 
+from quivr_core.llm import LLMEndpoint
 from quivr_core.rag.entities.chat import ChatHistory
 from quivr_core.rag.entities.config import RetrievalConfig
-from quivr_core.llm import LLMEndpoint
 from quivr_core.rag.entities.models import (
     ParsedRAGChunkResponse,
     ParsedRAGResponse,
@@ -24,6 +24,7 @@
 )
 from quivr_core.rag.prompts import custom_prompts
 from quivr_core.rag.utils import (
+    LangfuseService,
     combine_documents,
     format_file_list,
     get_chunk_metadata,
@@ -32,6 +33,8 @@
 )
 
 logger = logging.getLogger("quivr_core")
+langfuse_service = LangfuseService()
+langfuse_handler = langfuse_service.get_handler()
 
 
 class IdempotentCompressor(BaseDocumentCompressor):
@@ -173,7 +176,7 @@ def answer(
                 "chat_history": history,
                 "custom_instructions": (self.retrieval_config.prompt),
             },
-            config={"metadata": metadata},
+            config={"metadata": metadata, "callbacks": [langfuse_handler]},
         )
         response = parse_response(
             raw_llm_response, self.retrieval_config.llm_config.model
@@ -206,7 +209,7 @@ async def answer_astream(
                 "chat_history": history,
                 "custom_personality": (self.retrieval_config.prompt),
             },
-            config={"metadata": metadata},
+            config={"metadata": metadata, "callbacks": [langfuse_handler]},
         ):
             # Could receive this anywhere so we need to save it for the last chunk
             if "docs" in chunk:

core/quivr_core/rag/quivr_rag_langgraph.py

@@ -28,8 +28,6 @@
 from langgraph.types import Send
 from pydantic import BaseModel, Field
 
-from langfuse.callback import CallbackHandler
-
 from quivr_core.llm import LLMEndpoint
 from quivr_core.llm_tools.llm_tools import LLMToolFactory
 from quivr_core.rag.entities.chat import ChatHistory
@@ -41,6 +39,7 @@
 )
 from quivr_core.rag.prompts import custom_prompts
 from quivr_core.rag.utils import (
+    LangfuseService,
     collect_tools,
     combine_documents,
     format_file_list,
@@ -50,8 +49,8 @@
 
 logger = logging.getLogger("quivr_core")
 
-# Initialize Langfuse CallbackHandler for Langchain (tracing)
-langfuse_handler = CallbackHandler()
+langfuse_service = LangfuseService()
+langfuse_handler = langfuse_service.get_handler()
 
 
 class SplittedInput(BaseModel):
@@ -502,7 +501,7 @@ async def rewrite(self, state: AgentState) -> AgentState:
         task_ids = [jobs[1] for jobs in async_jobs] if async_jobs else []
 
         # Replace each question with its condensed version
-        for response, task_id in zip(responses, task_ids):
+        for response, task_id in zip(responses, task_ids, strict=False):
             tasks.set_definition(task_id, response.content)
 
         return {**state, "tasks": tasks}
@@ -558,7 +557,7 @@ async def tool_routing(self, state: AgentState):
         )
         task_ids = [jobs[1] for jobs in async_jobs] if async_jobs else []
 
-        for response, task_id in zip(responses, task_ids):
+        for response, task_id in zip(responses, task_ids, strict=False):
             tasks.set_completion(task_id, response.is_task_completable)
             if not response.is_task_completable and response.tool:
                 tasks.set_tool(task_id, response.tool)
@@ -599,7 +598,7 @@ async def run_tool(self, state: AgentState) -> AgentState:
         )
         task_ids = [jobs[1] for jobs in async_jobs] if async_jobs else []
 
-        for response, task_id in zip(responses, task_ids):
+        for response, task_id in zip(responses, task_ids, strict=False):
             _docs = tool_wrapper.format_output(response)
             _docs = self.filter_chunks_by_relevance(_docs)
             tasks.set_docs(task_id, _docs)
@@ -652,7 +651,7 @@ async def retrieve(self, state: AgentState) -> AgentState:
         task_ids = [task[1] for task in async_jobs] if async_jobs else []
 
         # Process responses and associate docs with tasks
-        for response, task_id in zip(responses, task_ids):
+        for response, task_id in zip(responses, task_ids, strict=False):
             _docs = self.filter_chunks_by_relevance(response)
             tasks.set_docs(task_id, _docs)  # Associate docs with the specific task
 
@@ -715,7 +714,7 @@ async def dynamic_retrieve(self, state: AgentState) -> AgentState:
             task_ids = [jobs[1] for jobs in async_jobs] if async_jobs else []
 
             _n = []
-            for response, task_id in zip(responses, task_ids):
+            for response, task_id in zip(responses, task_ids, strict=False):
                 _docs = self.filter_chunks_by_relevance(response)
                 _n.append(len(_docs))
                 tasks.set_docs(task_id, _docs)

core/quivr_core/rag/utils.py

@@ -4,6 +4,7 @@
 from langchain_core.messages import AIMessage, BaseMessage, HumanMessage, SystemMessage
 from langchain_core.messages.ai import AIMessageChunk
 from langchain_core.prompts import format_document
+from langfuse.callback import CallbackHandler
 
 from quivr_core.rag.entities.config import WorkflowConfig
 from quivr_core.rag.entities.models import (
@@ -195,3 +196,11 @@ def collect_tools(workflow_config: WorkflowConfig):
         activated_tools += f"Tool {i+1} description: {tool.description}\n\n"
 
     return validated_tools, activated_tools
+
+
+class LangfuseService:
+    def __init__(self):
+        self.langfuse_handler = CallbackHandler()
+
+    def get_handler(self):
+        return self.langfuse_handler