Release v1.15.0-rc.2/v0.38.0-rc.2

[MrAlias]

This is a release candidate for the v1.15.0/v0.38.0 release. That release will include the v1 release of the OpenTelemetry Go metric API and will provide stability guarantees of that API. See our versioning policy for more information about these stability guarantees.

Added

• The WithHostID option to go.opentelemetry.io/otel/sdk/resource. (add host.id to resource auto-detection #3812)
• The WithoutTimestamps option to go.opentelemetry.io/otel/exporters/stdout/stdoutmetric to sets all timestamps to zero. (New stdoutmetric encoder with ignore timestamp #3828)
• The new Exemplar type is added to go.opentelemetry.io/otel/sdk/metric/metricdata. Both the DataPoint and HistogramDataPoint types from that package have a new field of Exemplars containing the sampled exemplars for their timeseries. (Add Exemplar to metricdata package #3849)
• Configuration for each metric instrument in go.opentelemetry.io/otel/sdk/metric/instrument. (Split metric configuration down to instrument #3895)
• The internal logging introduces a warning level verbosity equal to V(1). (Enhance internal logging #3900)

Changed

• Optimize memory allocation when creation a new Set using NewSet or NewSetWithFiltered in go.opentelemetry.io/otel/attribute. (Pool sortables used to create attribute sets #3832)
• Optimize memory allocation when creation new metric instruments in go.opentelemetry.io/otel/sdk/metric. (Pool sortables used to create attribute sets #3832)
• Avoid creating new objects on all calls to WithDeferredSetup and SkipContextSetup in OpenTracing bridge. (Avoid creating new references on WithDeferredSetup for every span #3833)
• The New and Detect functions from go.opentelemetry.io/otel/sdk/resource return errors that wrap underlying errors instead of just containing the underlying error strings. (Wrap errors returned from Detect and New in sdk/resource #3844)
• Both the Histogram and HistogramDataPoint are redefined with a generic argument of [N int64 | float64] in go.opentelemetry.io/otel/sdk/metric/metricdata. (Add Exemplar to metricdata package #3849)
• The metric Export interface from go.opentelemetry.io/otel/sdk/metric accepts a *ResourceMetrics instead of ResourceMetrics. (Update the metric Export interface to accept a *ResourceMetrics instead of ResourceMetrics #3853)
• Rename Asynchronous to Observable in go.opentelemetry.io/otel/metric/instrument. (Remove Synchronous and rename Asynchronous #3892)
• Rename Int64ObserverOption to Int64ObservableOption in go.opentelemetry.io/otel/metric/instrument. (Split metric configuration down to instrument #3895)
• Rename Float64ObserverOption to Float64ObservableOption in go.opentelemetry.io/otel/metric/instrument. (Split metric configuration down to instrument #3895)
• The internal logging changes the verbosity level of info to V(4), the verbosity level of debug to V(8). (Enhance internal logging #3900)

Fixed

• TracerProvider consistently doesn't allow to register a SpanProcessor after shutdown. (Make TracerProvider not allow to register a SpanProcessor after shutdown #3845)

Removed

• The deprecated go.opentelemetry.io/otel/metric/global package is removed. (Remove the deprecated otel/metric/global pkg #3829)
• The unneeded Synchronous interface in go.opentelemetry.io/otel/metric/instrument was removed. (Remove Synchronous and rename Asynchronous #3892)
• The Float64ObserverConfig and NewFloat64ObserverConfig in go.opentelemetry.io/otel/sdk/metric/instrument. Use the added float64 instrument configuration instead. (Split metric configuration down to instrument #3895)
• The Int64ObserverConfig and NewInt64ObserverConfig in go.opentelemetry.io/otel/sdk/metric/instrument. Use the added int64 instrument configuration instead. (Split metric configuration down to instrument #3895)
• The NewNoopMeter function in go.opentelemetry.io/otel/metric, use NewMeterProvider().Meter("") instead. (Move metric No-Op to metric/noop #3893)

[codecov]

Codecov Report

Merging #3923 (0ab71db) into main (68d66f2) will decrease coverage by 0.1%.
The diff coverage is 100.0%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3923     +/-   ##
=======================================
- Coverage   81.8%   81.7%   -0.1%     
=======================================
  Files        170     170             
  Lines      12909   12909             
=======================================
- Hits       10561   10559      -2     
- Misses      2129    2131      +2     
  Partials     219     219             

Impacted Files	Coverage Δ
version.go	100.0% <100.0%> (ø)

... and 1 file with indirect coverage changes

[pellared]

I created two doc-related PRs that may be good to merge before the release:

• Add missing doc comments for Observer interfaces #3928
• metric: Refactor examples to use otel.Meter #3927