Multiple traces created for a single LiveKit call instead of one unified trace

[gulamsarvar-bluebash]

Hi team,

I’m integrating Langfuse with LiveKit, and I’m running into an issue with trace management.

Currently, for a single call/session in LiveKit, Langfuse is automatically creating multiple traces instead of keeping everything under one unified trace. My goal is to have one trace per call/session, with child spans inside that trace for different steps (LLM calls, tool usage, events, etc.).

Even though I’m explicitly setting up a root span and trace in my custom method

Langfuse still creates separate traces for events happening during the same call.

Questions:
How can I prevent Langfuse from creating multiple traces automatically in LiveKit integration?
Is there a way to disable auto-trace creation and use only my custom trace management logic?

[longcw]

I am also not sure why this would happen, a workaround is adding a session id langfuse.session.id to the spans so they will be grouped into a single session in langfuse https://github.com/livekit/agents/blob/livekit-agents@1.2.8/examples/voice_agents/langfuse_trace.py#L112.

[badbye]

Encountered the same issue (occurs unstably):

[longcw]

probably fixed by #3454

[marctorsoc]

Seeing this again since the update to 3.1 from 2.1.18. All traces have the same session_id. But for some reason, a new trace is created for every interaction (LLM response, TTS, etc). This is my integration code based on the example:

def get_trace_provider() -> TracerProvider:
    public_key = os.getenv("LANGFUSE_PUBLIC_KEY")
    secret_key = os.getenv("LANGFUSE_SECRET_KEY")
    host = os.getenv("LANGFUSE_HOST")

    if not public_key or not secret_key or not host:
        raise ValueError("LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, and LANGFUSE_HOST must be set")

    langfuse_auth = base64.b64encode(f"{public_key}:{secret_key}".encode()).decode()
    os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = f"{host.rstrip('/')}/api/public/otel"
    os.environ["OTEL_EXPORTER_OTLP_HEADERS"] = f"Authorization=Basic {langfuse_auth}"

    trace_provider = TracerProvider()
    return trace_provider


def setup_langfuse(ctx: JobContext):
    logger.info("Setting up Langfuse tracing")

    trace_provider = get_trace_provider()
    trace_provider.add_span_processor(BatchSpanProcessor(OTLPSpanExporter()))

    # metadata will be set as attributes on all spans created by the tracer
    langfuse_session_id = ctx.room.name

    set_tracer_provider(
        trace_provider,
        metadata={
            "langfuse.session.id": langfuse_session_id,
            "langfuse.environment": os.getenv("LANGFUSE_TRACING_ENVIRONMENT", "dev"),
        },
    )

    async def flush_trace():
        logger.info("Flushing Langfuse trace")
        trace_provider.force_flush()

    ctx.add_shutdown_callback(flush_trace)