feat(span_processor): add debug mode for abandoned spans #107
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# Motivation This feature is inspired from the go tracer DataDog/dd-trace-go#2188 It's hard to understand and locate spans that are never finished. This PR adds a debug mode to the tracer that will track the age and root span name of traces, and * log warnings from time to time if the traces are older than some amount of time. * log warning if some traces are still open during tracer shutdown # Implementation This feature should not add any cost to the tracer if it is not enabled, but requires storing some extra data associated with each trace. In order to not use any extra memory if the feature is not enabled, I track it in an additional registry which is only used in debug mode. This registry tracks the root span name, and the age of the trace. The debug mode is controlled by 2 new configurations: * DD_TRACE_DEBUG_OPEN_SPANS * DD_TRACE_OPEN_SPAN_TIMEOUT In order to test this feature correctly, I added extra code to intercept and store logs during integration tests. This is done through a thread local Logger, which is overridden and propagated locally during tests. Everything is hidden behind the test-utils feature and should thus be zero cost
bantonsson
reviewed
Nov 7, 2025
supported-configurations.json
Outdated
| "propertyKeys": ["trace_debug_open_spans"] | ||
| } | ||
| ], | ||
| "DD_TRACE_OPEN_SPAN_TIMEOUT": [ |
Collaborator
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This one is in the wrong alphabetical order. I also think it's weird that it's not named in the same way as DD_TRACE_DEBUG_OPEN_SPANS, since it's related. Naming it DD_TRACE_DEBUG_OPEN_SPANS_TIMEOUT would make more sense.
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Author
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I agree, I picked these names because they were the ones used by the go tracer for it's debug mode
I'll probably change the timeout one to DD_TRACE_DEBUG_OPEN_SPANS_TIMEOUT, as I don't think it's that bad to have different configs between languages in this specific case
bantonsson
approved these changes
Nov 10, 2025
iunanua
reviewed
Nov 10, 2025
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| #[cfg(feature = "test-utils")] | ||
| wait_agent_info_ready: default.wait_agent_info_ready, | ||
| span_metrics_interval: default.span_metrics_interval, |
Collaborator
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is missing here a #[cfg(feature = "test-utils")]?
Suggested change
| #[cfg(feature = "test-utils")] | |
| wait_agent_info_ready: default.wait_agent_info_ready, | |
| span_metrics_interval: default.span_metrics_interval, | |
| #[cfg(feature = "test-utils")] | |
| wait_agent_info_ready: default.wait_agent_info_ready, | |
| #[cfg(feature = "test-utils")] | |
| span_metrics_interval: default.span_metrics_interval, |
iunanua
reviewed
Nov 10, 2025
Comment on lines
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| #[cfg(feature = "test-utils")] | ||
| wait_agent_info_ready: false, | ||
| span_metrics_interval: Duration::from_secs(10), |
Collaborator
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and here?
Suggested change
| #[cfg(feature = "test-utils")] | |
| wait_agent_info_ready: false, | |
| span_metrics_interval: Duration::from_secs(10), | |
| #[cfg(feature = "test-utils")] | |
| wait_agent_info_ready: false, | |
| #[cfg(feature = "test-utils")] | |
| span_metrics_interval: Duration::from_secs(10), |
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Motivation
This feature is inspired from the go tracer DataDog/dd-trace-go#2188
It's hard to understand and locate spans that are never finished. This PR adds a debug mode to the tracer that will track the age and root span name of traces, and
Implementation
This feature should not add any cost to the tracer if it is not enabled, but requires storing some extra data associated with each trace.
In order to not use any extra memory if the feature is not enabled, I track it in an additional registry which is only used in debug mode.
This registry tracks the root span name, and the age of the trace.
The debug mode is controlled by 2 new configurations:
In order to test this feature correctly, I added extra code to intercept and store logs during integration tests. This is done through a thread local Logger, which is overridden and propagated locally during tests.
Everything is hidden behind the test-utils feature and should thus be zero cost