prometheus/client_golang v1.25.0-rc.0 on GitHub

⚠️ This release raises the minimum required Go version to 1.26 and includes breaking API changes in api/prometheus/v1 (see the [CHANGE] entries below). ⚠️

1.25.0-rc.0 / 2026-10-05

[CHANGE] Minimum required Go version is now 1.26, only the two latest Go versions (1.26 and 1.27) are supported from now on. #2138
[CHANGE] api/prometheus/v1: Query, QueryRange, Series, LabelNames, and LabelValues now return Infos annotations in addition to Warnings, matching the Prometheus server's info annotations. This changes the signatures of these methods and of api.Client's Do/DoGetFallback; custom API client implementations must be updated. #1963
[CHANGE] api/prometheus/v1: Rework TSDBBlocks result types to align with the Prometheus server's tsdb.BlockMeta: TSDBBlocksResult now contains Blocks []TSDBBlockMeta directly instead of mirroring the full API envelope, nested types are renamed (TSDBBlockMeta, TSDBBlockStats, TSDBBlockMetaCompaction), stat fields are uint64 with omitempty tags, and the optional compaction parents field is included. #1928
[FEATURE] testutil: Add GatherAndFormat to encode a subset of metrics from a Gatherer. #2091
[FEATURE] promhttp: Add HandlerOpts.AcceptedFormats to customize the formats negotiated from the incoming Accept header, enabling opt-in to experimental formats such as OpenMetrics 2.0 without changing default negotiation. #2146
[ENHANCEMENT] promhttp: Negotiated metrics responses now include a Vary header. #2142
[ENHANCEMENT] prometheus: Regenerate the default runtime collector metrics for Go 1.25 and Go 1.26. #2090, #2095
[ENHANCEMENT] testutil: Finalize OpenMetrics output in GatherAndFormat and CollectAndFormat (terminating # EOF). #2125
[BUGFIX] api: Match complete URL path placeholders only; a :foo argument no longer substitutes inside :foobar. #2136
[BUGFIX] exp/api/remote: Reset the pooled buffer before generic proto marshaling, preventing corrupted remote-write payloads. #2139
[BUGFIX] testutil/promlint: Fix "mibi" unit prefix to "mebi". #2135

What's changed

What's Changed

fix: Remove unneeded and broken CI badge by @bwplotka in #2057
Synchronize common files from prometheus/prometheus by @prombot in #2060
build(deps): bump the codeql group with 4 updates by @dependabot[bot] in #2066
build(deps): bump github.com/klauspost/compress from 1.19.0 to 1.19.1 by @dependabot[bot] in #2071
build(deps): bump golang.org/x/sys from 0.46.0 to 0.47.0 in the golang-org-x group across 1 directory by @dependabot[bot] in #2069
build(deps): bump github.com/klauspost/compress from 1.19.0 to 1.19.1 in /exp by @dependabot[bot] in #2072
build(deps): bump github.com/prometheus/common from 0.69.0 to 0.70.1 in /exp by @dependabot[bot] in #2073
build(deps): bump github.com/prometheus/common from 0.69.0 to 0.70.1 by @dependabot[bot] in #2070
build(deps): bump google.golang.org/grpc from 1.79.3 to 1.82.1 in /tutorials/whatsup by @dependabot[bot] in #2075
Pin GitHub Actions by @SuperQ in #2074
build(deps): bump actions/checkout from 7.0.0 to 7.0.1 by @dependabot[bot] in #2067
promhttp: fix panic on requests with nil URL by @SAY-5 in #2065
Return info annotations in addition to warnings in the API by @zenador in #1963
build(deps): bump ossf/scorecard-action from 2.4.3 to 2.4.4 by @dependabot[bot] in #2082
Synchronize common files from prometheus/prometheus by @prombot in #2084
Synchronize common files from prometheus/prometheus by @prombot in #2086
Synchronize common files from prometheus/prometheus by @prombot in #2088
Regenerate Go collector runtime metrics for Go 1.25 and Go 1.26 by @bwplotka in #2090
go.mod: remove obsolete exclude rule by @thaJeztah in #2077
Synchronize common files from prometheus/prometheus by @prombot in #2093
README: document the OpenTelemetry OTLP push bridge by @mvanhorn in #1987
docs: add AGENTS.md contributor and maintainer guide by @bwplotka in #2056
testutil: add GatherAndFormat helper by @wieghx in #2091
build(deps): bump the codeql group with 4 updates by @dependabot[bot] in #2101
build(deps): bump google.golang.org/protobuf from 1.36.11 to 1.36.12 by @dependabot[bot] in #2097
build(deps): bump github.com/klauspost/compress from 1.19.1 to 1.19.2 by @dependabot[bot] in #2098
build(deps): bump google.golang.org/protobuf from 1.36.11 to 1.36.12 in /exp by @dependabot[bot] in #2099
build(deps): bump github.com/klauspost/compress from 1.19.1 to 1.19.2 in /exp by @dependabot[bot] in #2100
build(deps): bump github.com/prometheus/procfs from 0.21.1 to 0.22.0 in the prometheus group across 1 directory by @dependabot[bot] in #2096
build(deps): bump google.golang.org/grpc from 1.82.1 to 1.83.1 in /tutorials/whatsup by @dependabot[bot] in #2102
chore: Update metrics for new Go version by @github-actions[bot] in #2095
Benchmark json-iter, stdlib json and json/v2 by @liggitt in #2107
build(deps): bump google.golang.org/grpc from 1.83.1 to 1.83.2 in /tutorials/whatsup by @dependabot[bot] in #2112
RuleGroup: use stdlib for json decoding, optimize decoding by @liggitt in #2109
Modernize micro benchmarks: b.Loop and key=value case names by @radianceded in #2114
QueryResult: use stdlib for envelope decoding by @liggitt in #2110
Use stdlib to decode apiResult envelope by @liggitt in #2111
Improve linting by @SuperQ in #2115
Delete unused custom json-iterator marshaling by @liggitt in #2121
Simplify apiClientImpl#Do error path by @liggitt in #2120
testutil: finalize OpenMetrics output by @ajavanma in #2125
build(deps): bump go.opentelemetry.io/otel/sdk from 1.44.0 to 1.45.0 in /tutorials/whatsup by @dependabot[bot] in #2124
Synchronize common files from prometheus/prometheus by @prombot in #2116
prometheus: fix revive indent-error-flow lint on Darwin by @bwplotka in #2131
build(deps): bump go.opentelemetry.io/otel/exporters/otlp/otlptrace from 1.34.0 to 1.45.0 in /tutorials/whatsup by @dependabot[bot] in #2123
Combine envelope/inner apiResponse decoding, switch to stdlib json by @liggitt in #2118
build(deps): bump go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc from 1.34.0 to 1.45.0 in /tutorials/whatsup by @dependabot[bot] in #2122
testutil/promlint: fix "mibi" unit prefix to "mebi" by @ZainnQureshii in #2135
all: update prometheus/common to v0.72.0 and apply modernize fixes by @bwplotka in #2138
limit json-iterator use to Go 1.26 by @liggitt in #2128
promhttp: add AcceptedFormats option to customize format negotiation by @bwplotka in #2146
build(deps): bump github.com/klauspost/compress from 1.19.2 to 1.20.1 by @dependabot[bot] in #2143
build(deps): bump the codeql group with 4 updates by @dependabot[bot] in #2145
build(deps): bump github.com/klauspost/compress from 1.19.2 to 1.20.1 in /exp by @dependabot[bot] in #2144
promhttp: vary negotiated metrics responses by @lowgame in #2142
exp/api/remote: reset pooled buffer before generic marshal by @lowgame in #2139
api: match complete URL placeholders by @lowgame in #2136
fix: updates for tsdb blocks handling by @tjhop in #1928
prometheus: fix modernize lint findings by @kakkoyun in #2151
build(deps): bump google.golang.org/grpc from 1.82.1 to 1.83.2 in /api/prometheus/v1/paritytest by @dependabot[bot] in #2152
Cut v1.25.0-rc.0 by @kakkoyun in #2154

New Contributors

@SAY-5 made their first contribution in #2065
@zenador made their first contribution in #1963
@thaJeztah made their first contribution in #2077
@mvanhorn made their first contribution in #1987
@wieghx made their first contribution in #2091
@radianceded made their first contribution in #2114
@ajavanma made their first contribution in #2125
@ZainnQureshii made their first contribution in #2135
@lowgame made their first contribution in #2142

Full Changelog: v1.24.1...v1.25.0-rc.0