Inferred spans #1340
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Inferred spans #1340
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JonasKunz
commented
Jun 10, 2024
| AttributeKey.stringKey("code.stacktrace"); | ||
| public static final AttributeKey<Boolean> LINK_IS_CHILD = AttributeKey.booleanKey("is_child"); | ||
| public static final AttributeKey<Boolean> SPAN_IS_INFERRED = | ||
| AttributeKey.booleanKey("is_inferred"); |
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is_child and is_inferred are feature-specific attributes which I don't see as candidated for SemConv.
Is there a best-practice for namespacing such attributes? E.g. to use the feature name as prefix (inferred_spans.)?
| static final String EXCLUDED_CLASSES_OPTION = "otel.inferred.spans.excluded.classes"; | ||
| static final String INTERVAL_OPTION = "otel.inferred.spans.interval"; | ||
| static final String DURATION_OPTION = "otel.inferred.spans.duration"; | ||
| static final String LIB_DIRECTORY_OPTION = "otel.inferred.spans.lib.directory"; |
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Is there any recommended namespace here to use for the config options? Or is otel.inferred.spans fine?
jackshirazi
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Jun 11, 2024
SylvainJuge
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Jun 12, 2024
trask
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Jun 17, 2024
...c/test/java/io/opentelemetry/contrib/inferredspans/internal/asyncprofiler/JfrParserTest.java
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...-spans/src/main/java/io/opentelemetry/contrib/inferredspans/internal/pooling/ObjectPool.java
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trask
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Jun 17, 2024
...pans/src/test/java/io/opentelemetry/contrib/inferredspans/internal/SamplingProfilerTest.java
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...pans/src/test/java/io/opentelemetry/contrib/inferredspans/internal/SamplingProfilerTest.java
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SylvainJuge
approved these changes
Jun 20, 2024
|
@JonasKunz sorry, can you resolve new merge conflict? thanks |
# Conflicts: # dependencyManagement/build.gradle.kts
SylvainJuge
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Jul 11, 2024
jackshirazi
approved these changes
Jul 11, 2024
This was referenced Sep 18, 2024
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Description:
This PR adds an OpenTelemetry SDK Extension (SpanProcessor) for enriching traces with "inferred" spans derived from profiling data. It internally uses async-profiler 3.0 in wall-clock profiling mode.
This feature was originally added a few years ago to the Elastic APM Agent, we recently ported it to OpenTelemetry in our OpenTelemetry distro and would now like to contribute it to the OpenTelemetry community.
The feature works by keeping track of which spans are activated/deactivated on which threads via the OpenTelemetry context API. A log of these activations/deactivations is spilled to disk, while at the same time async-profiler is enabled to profile threads with active spans. After the profiling session ends (default is 10 seconds), the profiling JFR and the log of span activations is used to generate the synthetic inferred spans. Here is also a blogpost about the feature.
Because this feature was initially written for the classic Elastic APM Agent, it heavily tries to minimize allocations. As a result, the feature is almost allocation free, which unfortunately comes at the cost of a bit more complex code due to pooling.
Testing:
The algorithm for span inference has been ported without changes from the classic Elastic APM Agent and therefore is relatively battle tested. The PR also comes with a large set of test-cases for edge cases of the inference algorithm.
Documentation:
Just the README.MD added on how to use this extension either by manual setup or using SDK auto configuration.
It also documents some limitations of the inference algorithm.