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Anyone else having trouble with the Python SDK in async applications?

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(@amandaj)
Reputable Member
Joined: 1 week ago
Posts: 148
Topic starter   [#17563]

I've been conducting a deep evaluation of Traceloop's observability platform for my team's event-driven analytics pipeline, which is built heavily on Python's `asyncio`. While I appreciate the depth of telemetry the platform promises, I've encountered significant and persistent challenges when integrating the official `traceloop-sdk` into asynchronous application contexts.

My primary issue revolves around span creation and context propagation within concurrent tasks. The SDK seems to lose context when operations are yielded, leading to orphaned spans or spans with incorrect parent-child relationships. This, of course, completely breaks the utility of the trace for any meaningful funnel or user behavior analysis, as the causal sequence of events is lost.

Here is a simplified example of the pattern that consistently fails:

```python
import asyncio
from traceloop.sdk import Traceloop

Traceloop.init(app_name="async_test")

async def nested_operation(item_id: int):
# This often becomes a root span, not a child of `process_items`
with Traceloop.start_span(name=f"process_item_{item_id}"):
await asyncio.sleep(0.1)
return item_id * 2

async def main_workflow():
with Traceloop.start_span(name="process_items"):
tasks = [nested_operation(i) for i in range(3)]
results = await asyncio.gather(*tasks)
return results

# Running this results in a flat trace of four independent spans.
asyncio.run(main_workflow())
```

**Specific symptoms observed:**

* **Context Loss in Gather/Gather Unordered:** Child spans created inside tasks executed via `asyncio.gather` do not maintain the parent span context.
* **Inconsistent with OpenTelemetry:** The SDK's async support appears to lag behind the current OpenTelemetry Python SDK's capabilities for context management using `opentelemetry.context`.
* **Blocking Operations:** There are indications that some instrumentation wrappers introduce blocking calls, which can negate the performance benefits of an async architecture.

I have attempted workarounds, such as manually passing context tokens or using the underlying OpenTelemetry API directly, but this defeats the purpose of using Traceloop's abstraction layer. My current hypothesis is that the SDK's decorators and context managers are not fully leveraging `contextvars` for async context isolation.

My questions for the community are:

1. Has anyone successfully deployed the Traceloop Python SDK in a high-concurrency `asyncio` or `FastAPI` application? If so, what was your configuration pattern?
2. Are there known best practices or required monkey patches to ensure span hierarchy is preserved across `await` boundaries?
3. Is this a recognized limitation in the current SDK version, and is there a roadmap for first-class async support?

I am preparing a detailed comparison table of observability tools focusing on async Python support, and the resolution of this issue will significantly impact my evaluation. Any shared experiences or insights would be invaluable.

— Amanda


Data > opinions


   
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(@data_pipeline_rookie_42)
Estimable Member
Joined: 3 months ago
Posts: 93
 

Yeah, we ran into the same parent-child mapping issue when instrumenting our async data ingestion tasks. It's like the SDK's context carrier doesn't survive the event loop switch. We had to wrap our task creation in a specific pattern.

Instead of just `asyncio.create_task(nested_operation(item_id))`, we started manually passing a parent context. Something like:

```python
ctx = Traceloop.get_current_context()
task = asyncio.create_task(nested_operation(item_id, parent_ctx=ctx))
```

And then inside the task, you have to set that context before starting the span. It's a total pain and feels like the SDK should handle this. Have you found any workarounds that are less manual? I'm scared to roll this out to production without it being rock solid.



   
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