core-1.9.0-alpha.1

• NuGet: OpenTelemetry v1.9.0-alpha.1

  • Experimental (pre-release builds only): Exposed ExemplarReservoir as a
    public API and added support for setting an ExemplarReservoir factory
    function when configuring a view (applies to individual metrics).
    (#5542)

  • Fixed a race condition for the experimental MetricPoint reclaim scenario
    (enabled via OTEL_DOTNET_EXPERIMENTAL_METRICS_RECLAIM_UNUSED_METRIC_POINTS)
    which could have led to a measurement being dropped.
    (#5546)

  • Experimental (pre-release builds only): Exposed
    FixedSizeExemplarReservoir as a public API to support custom implementations
    of ExemplarReservoir which may be configured using the
    ExemplarReservoirFactory property on the View API.
    (#5558)

  • The experimental APIs previously covered by OTEL1002 (Exemplar,
    ExemplarFilterType, MeterProviderBuilder.SetExemplarFilter,
    ReadOnlyExemplarCollection, ReadOnlyFilteredTagCollection, &
    MetricPoint.TryGetExemplars) will now be part of the public API and
    supported in stable builds.
    (#5607)

  • Fixed the nullable annotations for the SamplingResult constructors
    to allow null being supplied as attributes or traceStateString
    which has always been supported.
    (#5614)

  • The ExemplarFilter used by SDK MeterProviders for histogram metrics can
    now be controlled via the experimental
    OTEL_DOTNET_EXPERIMENTAL_METRICS_EXEMPLAR_FILTER_HISTOGRAMS environment
    variable. The supported values are: always_off, always_on, and
    trace_based.
    (#5611)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.9.0-alpha.1

  • Breaking change: Fix space character encoding from + to %20
    for baggage item values when propagating baggage as defined in
    W3C Baggage propagation format specification.
    (#5303)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.9.0-alpha.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.9.0-alpha.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.9.0-alpha.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.9.0-alpha.1

  • User-Agent header format changed from
    OTel-OTLP-Exporter-Dotnet/{NuGet Package Version}+{Commit Hash}
    to OTel-OTLP-Exporter-Dotnet/{NuGet Package Version}.
    (#5528)

  • Implementation of OTLP
    specification
    for propagating Span and SpanLink flags containing W3C trace flags and
    parent_is_remote information.
    (#5563)

  • Introduced experimental support for automatically retrying export to the otlp
    endpoint by storing the telemetry offline during transient network errors.
    Users can enable this feature by setting the
    OTEL_DOTNET_EXPERIMENTAL_OTLP_RETRY environment variable to disk. The
    default path where the telemetry is stored is obtained by calling
    Path.GetTempPath()
    or can be customized by setting
    OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH environment
    variable.
    (#5527)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.9.0-alpha.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.9.0-alpha.1

  • Reverted obsoletion of OpenTelemetryBuilder.
    (#5571)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Propagators v1.9.0-alpha.1

  No notable changes.

  See CHANGELOG for details.