Phoenix tracing broken, only "workflow" chain arrived

[Graf2242]

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Dify version

1.9.0

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

1. Create any workflow
2. Set up phoenix monitoring for this workflow
3. Run workflow

Also, here is worker logs:

2025-09-25 15:17:28.686 ERROR [Dummy-12] [arize_phoenix_trace.py:154] - [Arize/Phoenix] Error in the trace: 'str' object has no attribute 'created_at'
Traceback (most recent call last):
  File "/app/api/core/ops/arize_phoenix_trace/arize_phoenix_trace.py", line 139, in trace
    self.workflow_trace(trace_info)
  File "/app/api/core/ops/arize_phoenix_trace/arize_phoenix_trace.py", line 195, in workflow_trace
    created_at = node_execution.created_at or datetime.now()
                 ^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'created_at'
2025-09-25 15:17:28.690 INFO [Dummy-12] [ops_trace_task.py:50] - error:
'str' object has no attribute 'created_at'

Also, here is what i see in Phoenix

✔️ Expected Behavior

I got whole detailed trace in Phoenix

And how it look with Dify 1.8.0

❌ Actual Behavior

I got only "root" Workflow trace, but no any node traces

[dosubot]

This issue is a known bug in Dify 1.9.0: Phoenix tracing only shows the root workflow trace and not node-level traces because of a code limitation and a guard clause that skipped tracing when message_data was None. This also led to the 'str' object has no attribute 'created_at' error, since the code expected a node execution object but received a string instead. The fix for this was merged in PR #22547, which removes the problematic guard, ensures node executions are properly traced, and restores detailed node-level traces in Phoenix.

To resolve the issue, make sure your deployment includes the changes from PR #22547. If not, update your Dify instance or manually apply the patch. Once the fix is present, you should see full node-level traces in Phoenix and the AttributeError should disappear. More details and confirmation of the fix are in issue #22504.

To reply, just mention @dosu.

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