Langfuse Tracing not showing up on UI

[nthanapaisal]

Hi,

so I have a FastAPI app that retrieves prompts from Langfuse. I can retrieve prompts and trace_id from the code below but I cannot see traces inside the Langfuse UI project. I am unsure what I am doing wrong.

Langfuse SDK 2.52.0
Python 3.10.16

@router.post("/get_prompt")
async def route1(payload: RequestStruct)
 langfuse_client = Langfuse(
   secret=secret,
   public=public,
   host="hosturl",
   httpx_client=httpx.client(verify=cert),
   timeout=60
 )
 res = service(langfuse_client)
 langfuse_client .flush()

@observe()
def service(langfuse_client):
 return call_api(langfuse_client)

@observe(as_type="generation")
def call_api(langfuse_client):
  langfuse_context.update_current_trace(
    sesssion_id="abc123",
    user_id="1",
    tags=[]
 )
 trace_id = langfuse_context.get_current_trace_id()
  return  langfuse_client.get_prompt("prompt1", type="chat", version=1)
```

[dosubot[bot]]

Hello, @nthanapaisal! I'm here to help you with your Langfuse tracing issue. I'm a bot designed to assist with bug fixes, answer questions, and guide you in becoming a contributor. Let's work together to tackle this issue!

I found a similar discussion that might be helpful: Langgraph with langfuse, which was last updated on July 25, 2024. It includes examples and might provide insights into your issue ^[1].

For your specific issue, here are some troubleshooting steps to ensure traces appear in the Langfuse UI:

1. Verify API Credentials: Ensure that the secret and public keys used in your Langfuse client initialization match those in your Langfuse project settings.

2. Check Tracing Configuration: Make sure the host URL is correctly set to the appropriate Langfuse endpoint. If you are self-hosting or using a specific data region, ensure the host is configured accordingly.

3. Inspect Logs for Errors: Check your application logs for any errors related to Langfuse. Enable debug logging if necessary to get more detailed information.

4. Manual Flushing: Since you are using langfuse_client.flush(), ensure it is called at the right time to flush events before the application exits. This is crucial in short-lived applications.

5. Network Issues: Ensure there are no network issues preventing data from being sent to Langfuse. Verify that your network settings allow outbound connections to the Langfuse endpoints.

6. Batching Configuration: Adjust the batching configuration if necessary. Ensure that flushAt and flushInterval settings are appropriate for your application's throughput.

7. Custom Trace Properties: Ensure that the session_id, user_id, and tags are correctly set and that the trace_id is being properly updated and used.

8. Use of @observe() Decorator: The @observe() decorator should automatically handle traces and spans. Ensure it is correctly applied to the functions you want to trace.

By following these steps, you should be able to identify and resolve the issue preventing traces from appearing in the Langfuse UI ^[2].

To continue talking to Dosu, mention @dosu.

[jannikmaierhoefer]

Hi @nthanapaisal, If you are able to fetch the prompts they should also show up in the UI. Did you check if you are on the right project within the Langfuse UI? We recently introduced Organisations that can contain multiple Projects.

[jannikmaierhoefer]

Hi @nthanapaisal, did you manage to see your traces in the Langfuse UI?

[nthanapaisal]

hi

so I was calling observe incorrectly. The solution was to do it this way

#decorator
from langfuse.decorators import LangfuseDecorator
ld = LangfuseDecorator()
ld.configure(..)

# client
langfuse = Langfuse()

thanks!