Update module github.com/prometheus/client_golang to v1.21.1

v1.21.1: / 2025-03-04

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This release addresses a performance regression introduced in #​1661 -- thanks to all who reported this quickly: @​chlunde, @​dethi, @​aaronbee @​tsuna @​kakkoyun 💪🏽. This patch release also fixes the iOS build.

We will be hardening the release process even further (#​1759, #​1761) to prevent this in future, sorry for the inconvenience!

The high concurrency optimization is planned to be eventually reintroduced, however in a much safer manner, potentially in a separate API.

• [BUGFIX] prometheus: Revert of Inc, Add and Observe cumulative metric CAS optimizations (#​1661), causing regressions on low concurrency cases #​1757
• [BUGFIX] prometheus: Fix GOOS=ios build, broken due to process_collector_* wrong build tags. #​1758

Full Changelog: https://github.com/prometheus/client_golang/compare/v1.21.0...v1.21.1

v1.21.0: / 2025-02-19

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⚠️ This release contains potential breaking change if you upgrade github.com/prometheus/common to 0.62+ together with client_golang (and depend on the strict, legacy validation for the label names). New common version changes model.NameValidationScheme global variable, which relaxes the validation of label names and metric name, allowing all UTF-8 characters. Typically, this should not break any user, unless your test or usage expects strict certain names to panic/fail on client_golang metric registration, gathering or scrape. In case of problems change model.NameValidationScheme to old model.LegacyValidation value in your project init function. ⚠️

• [BUGFIX] gocollector: Fix help message for runtime/metric metrics. #​1583
• [BUGFIX] prometheus: Fix Desc.String() method for no labels case. #​1687
• [PERF] prometheus: Optimize popular prometheus.BuildFQName function; now up to 30% faster. #​1665
• [PERF] prometheus: Optimize Inc, Add and Observe cumulative metrics; now up to 50% faster under high concurrent contention. #​1661
• [CHANGE] Upgrade prometheus/common to 0.62.0 which changes model.NameValidationScheme global variable. #​1712
• [CHANGE] Add support for Go 1.23. #​1602
• [FEATURE] process_collector: Add support for Darwin systems. #​1600 #​1616 #​1625 #​1675 #​1715
• [FEATURE] api: Add ability to invoke CloseIdleConnections on api.Client using api.Client.(CloseIdler).CloseIdleConnections() casting. #​1513
• [FEATURE] promhttp: Add promhttp.HandlerOpts.EnableOpenMetricsTextCreatedSamples option to create OpenMetrics _created lines. Not recommended unless you want to use opt-in Created Timestamp feature. Community works on OpenMetrics 2.0 format that should make those lines obsolete (they increase cardinality significantly). #​1408
• [FEATURE] prometheus: Add NewConstNativeHistogram function. #​1654

New Contributors

• @​parthlaw made their first contribution in https://github.com/prometheus/client_golang/pull/1606
• @​mharbison72 made their first contribution in https://github.com/prometheus/client_golang/pull/1600
• @​cuisongliu made their first contribution in https://github.com/prometheus/client_golang/pull/1513
• @​ying-jeanne made their first contribution in https://github.com/prometheus/client_golang/pull/1626
• @​Manask322 made their first contribution in https://github.com/prometheus/client_golang/pull/1657
• @​jkroepke made their first contribution in https://github.com/prometheus/client_golang/pull/1665
• @​imorph made their first contribution in https://github.com/prometheus/client_golang/pull/1672
• @​mmorel-35 made their first contribution in https://github.com/prometheus/client_golang/pull/1676
• @​shivanthzen made their first contribution in https://github.com/prometheus/client_golang/pull/1654
• @​dashpole made their first contribution in https://github.com/prometheus/client_golang/pull/1699

Full Changelog: https://github.com/prometheus/client_golang/compare/v1.20.5...v1.21.0

v1.20.5: / 2024-10-15

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We decided to revert the testutil change that made our util functions less error-prone, but created a lot of work for our downstream users. Apologies for the pain! This revert should not cause any major breaking change, even if you already did the work--unless you depend on the exact error message.

Going forward, we plan to reinforce our release testing strategy [1],[2] and deliver an enhanced testutil package/module with more flexible and safer APIs.

Thanks to @​dashpole @​dgrisonnet @​kakkoyun @​ArthurSens @​vesari @​logicalhan @​krajorama @​bwplotka who helped in this patch release! 🤗

Changelog

[BUGFIX] testutil: Reverted #​1424; functions using compareMetricFamilies are (again) only failing if filtered metricNames are in the expected input. #​1645

v1.20.4

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• [BUGFIX] histograms: Fix a possible data race when appending exemplars vs metrics gather. #​1623