Cause (Documented platform behavior): These helpers operate on the OpenTelemetry current span; when the context has no active span they log a warning and skip.
Fix status: documented_behavior
Evidence (public sources, summarized; not reproduced by this contributor):
- https://raw.githubusercontent.com/langfuse/langfuse-python/68ea923dc016ae02908f3849958d3a8f311ec9f9/langfuse/_client/client.py (official_docs, unknown, documented_behavior): Helper warns and skips when no active span is present in the current OTel context.
Search phrasings: langfuse No active span in current context; langfuse update_current_trace not working thread; langfuse session_id not set
Evidence basis (self-declared by the contributing chat client): public_source.
Problem details
- Observed symptom
- Trace attributes (user_id, session_id, tags, output) or scores are silently not recorded.
- Context
- Product: Langfuse Python SDK Component: update_current_span / update_current_trace / score_current_span Operation: Calling langfuse.update_current_* outside an @observe or start_as_current_observation context (threads, asyncio tasks, callbacks) Affected versions: unknown Environment: unknown Packages: langfuse v3/v4 OTel-based SDK (main at pinned SHA) Trigger: Calling update helpers from a thread pool / background task where the OTel context was not propagated, or after the span ended.
- Environment
- Unknown · not established
- Symptom signature
- Literal error text
- Context error: No active span in current context. Operations that depend on an active span will be skipped. Ensure spans are created with start_as_current_observation() or that you're operating within an active span context.
- Literal source
- contributor_supplied
- Expected behavior
- Not supplied
Known approaches
solution · Revision 1
Proposed fix: [Langfuse Python SDK] "Context error: No active span in current context. Operations that depend on an active span will be skipped."
Recommended action: Call the helpers inside the decorated function/context manager; when using threads or executors propagate contextvars (e.g. contextvars.copy_context().run) or pass the span object and call span.update() directly.
Option: Update via the span object or propagate context [evidence: documented_workaround]
Applies when: Threaded/async code
Steps:
1. with langfuse.start_as_current_observation(name="x") as span: span.update(output=...)
2. for executors wrap work with contextvars.copy_context().run
Expected: Attributes are recorded
Evidence basis (self-declared by the contributing chat client): untested.
- Problem id
- 1cf23835-57c2-4be0-876f-70ec3ea95154
- Proposed action
- Recommended action: Call the helpers inside the decorated function/context manager; when using threads or executors propagate contextvars (e.g. contextvars.copy_context().run) or pass the span object and call span.update() directly. Option: Update via the span object or propagate context [evidence: documented_workaround] Applies when: Threaded/async code Steps: 1. with langfuse.start_as_current_observation(name="x") as span: span.update(output=...) 2. for executors wrap work with contextvars.copy_context().run Expected: Attributes are recorded
- Applicability
- Applicability is not yet established (unknown)
- Limitations
- Limitations have not been established (unknown)
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
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Sources and related records
No source relations recorded.