Limit exemplar label characters to conform to Prometheus limits#8362
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anuq wants to merge 6 commits into
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Limit exemplar label characters to conform to Prometheus limits#8362anuq wants to merge 6 commits into
anuq wants to merge 6 commits into
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #8362 +/- ##
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+ Coverage 90.88% 90.91% +0.03%
- Complexity 7985 7990 +5
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Files 898 898
Lines 24107 24123 +16
Branches 2406 2409 +3
============================================
+ Hits 21909 21932 +23
+ Misses 1455 1450 -5
+ Partials 743 741 -2 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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psx95
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May 9, 2026
| private static int labelSetLength(Labels labels) { | ||
| int length = 0; | ||
| for (int i = 0; i < labels.size(); i++) { | ||
| length += labels.getName(i).length() + labels.getValue(i).length(); |
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Looking at the OpenMetrics Exemplar spec, I think this function should be using codePointCount instead of length. This was also used in a previous PR addressing the same issue.
That PR already had reviews. Not sure if you've looked through that PR (it seems it has been inactive for a while now).
| assertThat(predicateCalledCount.get()).isEqualTo(2); | ||
| } | ||
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| @Test |
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Quick Question - would it be possible to convert these added unit tests into parameterized tests?
Addressed both suggestions: codePointCount instead of length() — Updated labelSetLength() to use String.codePointCount() so the limit is measured in Unicode code points, consistent with the OpenMetrics exemplar spec. (reference open-telemetry#6791) Parameterized tests — Consolidated the four exemplar label limit tests into a single @ParameterizedTest with @MethodSource, covering all four combinations (with/without span context × within/exceeding limit)
Addressed both suggestions: codePointCount instead of length() — Updated labelSetLength() to use String.codePointCount() so the limit is measured in Unicode code points, consistent with the OpenMetrics exemplar spec. (reference open-telemetry#6791) Parameterized tests — Consolidated the four exemplar label limit tests into a single @ParameterizedTest with @MethodSource, covering all four combinations (with/without span context × within/exceeding limit)
…github.com/anuq/opentelemetry-java into fix/prometheus-exemplar-label-length-limit # Conflicts: # exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverterTest.java
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Fixes #6770
Limits exemplar label characters to Prometheus's 128 UTF-8 character maximum. When labels exceed this limit, filtered attributes are dropped while preserving trace_id and span_id for correlation.
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