dataframer-journey 0.1.0

Automatic journey_id propagation for DataFramer — inbound extraction, outbound header injection, Langfuse trace stamping

dataframer-journey

Automatic journey_id propagation for DataFramer user-signal stitching. One line per service; after that the journey id flows browser → service → service → trace without anyone threading it by hand.

Install

pip install dataframer-journey

Zero runtime dependencies. Patches apply only to libraries you already have (requests, httpx, langfuse).

Usage

FastAPI / Starlette:

from dataframer_journey import instrument

app = FastAPI()
instrument(app)

Django — call instrument() at the end of settings.py and add the middleware:

MIDDLEWARE = [
    ...,
    'dataframer_journey.django.JourneyIdMiddleware',
]

import dataframer_journey
dataframer_journey.instrument()

That's it. From then on:

• Inbound: the journey id is read off each incoming request (baggage header → X-Journey-Id header → df_journey_id cookie set by @dataframer/signals) into request-scoped context.
• Outbound: every outgoing requests/httpx call automatically carries it to the next service (both X-Journey-Id and W3C baggage, so it also rides existing OpenTelemetry propagation). Explicitly-set headers are never overwritten.
• Traces: every Langfuse trace created during the request gets metadata.journey_id (and a journey:<id> tag) stamped automatically. Explicit metadata wins; the stamp is merge-if-absent.

Non-HTTP entry points (queue consumers, scheduled jobs): take the id from the payload yourself —

from dataframer_journey import with_journey, get_journey_id

with with_journey(payload["journey_id"]):
    ...  # traces created here are stamped; outbound calls carry the id

Notes

• Langfuse SDK v2 is supported; v3 (OpenTelemetry-based) stamping is not implemented yet and logs a warning.
• The browser side is @dataframer/signals, which generates the journey id and sends it on requests to your API.
• CORS: if your frontend and API are on different origins, allow the X-Journey-Id (or baggage) request header in your API's CORS config. Same-site setups need nothing — the cookie carries it.