Version 1.23.0

This release is a notable release for metrics:

• The base2 exponential histogram aggregation has been marked as stable. To use, configure your MetricExporter with a default aggregation of Aggregation.base2ExponentialBucketHistogram() for histogram instruments. If using OTLP exporter with autoconfigure, set OTEL_EXPORTER_OTLP_METRICS_DEFAULT_HISTOGRAM_AGGREGATION=BASE2_EXPONENTIAL_BUCKET_HISTOGRAM. If using configuring OTLP programatically, use Otlp*MetricExporterBuilder#setDefaultAggregationSelector(DefaultAggregationSelector).
• The metrics SDK undergone significant internal refactoring which results in reduced complexity and significantly reduced memory allocation during metric collection / export.

API

Logs

• WARNING: Split out Event API from Log API. Event API is now published in opentelemetry-api-events. API / SDK usage has also changed - see PR for details. (#5049)

SDK

• Add shutdown / close to OpenTelemetrySdk (#5100)

Metrics

• Base2 exponential histogram aggregations are now stable. Add base2ExponentialBucketHistogram() to Aggregation. (#5143)
• Promote exponential histogram data interfaces to stable package (#5120)
• Add Base2 prefix to internal exponential histogram classes (#5179)
• Add MaxScale config parameter to Base2ExponentialBucketHistogram (#5044)
• Add close method to MetricReader (#5109)
• Reuse AggregatorHandle with cumulative temporality to reduce allocations (#5142)
• Delete notion of accumulation to reduce allocations (#5154)
• Delete bound instruments (#5157)
• Reuse aggregation handles for delta temporality to reduce allocations (#5176)

Exporter

• Add proper shutdown implementations for all exporters (#5113)

SDK Extensions

• WARNING: Remove deprecated autoconfigure exemplar filter names. Previous names none, all , with_sampled_trace have been removed. Use always_off, always_on, trace_based instead. (#5098)
• Add autoconfigure support for "none" option for propagator value (#5121)
• Add autoconfigure support for parentbased_jaeger_remote sampler (#5123)
• Autoconfigure closes up autoconfigured resources in case of exception (#5117)
• View file based config has switched from snakeyaml to snakeyaml-engine for YAML parsing. (#5138)
• Fix autoconfigure resource providers property docs (#5135)

Testing

• WARNING: Merge opentelemetry-sdk-metrics-testing into opentelemetry-sdk-testing. Stop publishing opentelemetry-sdk-metrics-testing. (#5144)
• Sort spans by start time (parents before children as tiebreaker) to avoid common causes for flaky tests (#5026)
• Add resource assertion methods to SpanDataAssert and MetricAssert (#5160)

Semantic Conventions

• Update semconv to 1.18.0 (#5188) (#5134)

OpenTracing Shim

• Refactor to remove internal objects BaseShimObject and TelemetryInfo (#5087)
• WARNING: Minimize public surface area of OpenTracingShim. Remove createTracerShim() , createTracerShim(Tracer), createTracerShim(Tracer, OpenTracingPropagators). Add createTracerShim(TracerProvder,TextMapPropagator,TextMapPropagator). (#5110)

Project tooling

• Add OWASP dependency check (#5177)

🙇 Thank you

This release was possible thanks to the following contributors who shared their brilliant ideas and awesome pull requests:

@anuraaga
@bcmedeiros
@breedx-splk
@carlosalberto
@Donnerbart
@fsalvini
@ilteristabak
@jack-berg
@jkwatson
@mateuszrzeszutek
@rapphil
@stnor
@tigrannajaryan
@trask
@zeitlinger