This release implements the v0.5.0 version of the OpenTelemetry specification.

Added

• The othttp instrumentation now includes default metrics. (#861)
• This CHANGELOG file to track all changes in the project going forward.
• Support for array type attributes. (#798)
• Apply transitive dependabot go.mod dependency updates as part of a new automatic Github workflow. (#844)
• Timestamps are now passed to exporters for each export. (#835)
• Add new Accumulation type to metric SDK to transport telemetry from Accumulators to Processors.
  This replaces the prior Record struct use for this purpose. (#835)
• New dependabot integration to automate package upgrades. (#814)
• Meter and Tracer implementations accept instrumentation version version as an optional argument.
  This instrumentation version is passed on to exporters. (#811) (#805) (#802)
• The OTLP exporter includes the instrumentation version in telemetry it exports. (#811)
• Environment variables for Jaeger exporter are supported. (#796)
• New aggregation.Kind in the export metric API. (#808)
• New example that uses OTLP and the collector. (#790)
• Handle errors in the span SetName during span initialization. (#791)
• Default service config to enable retries for retry-able failed requests in the OTLP exporter and an option to override this default. (#777)
• New go.opentelemetry.io/otel/api/oterror package to uniformly support error handling and definitions for the project. (#778)
• New global default implementation of the go.opentelemetry.io/otel/api/oterror.Handler interface to be used to handle errors prior to an user defined Handler.
  There is also functionality for the user to register their Handler as well as a convenience function Handle to handle an error with this global Handler(#778)
• Options to specify propagators for httptrace and grpctrace instrumentation. (#784)
• The required application/json header for the Zipkin exporter is included in all exports. (#774)
• Integrate HTTP semantics helpers from the contrib repository into the api/standard package. #769

Changed

• Rename Integrator to Processor in the metric SDK. (#863)
• Rename AggregationSelector to AggregatorSelector. (#859)
• Rename SynchronizedCopy to SynchronizedMove. (#858)
• Rename simple integrator to basic integrator. (#857)
• Merge otlp collector examples. (#841)
• Change the metric SDK to support cumulative, delta, and pass-through exporters directly.
  With these changes, cumulative and delta specific exporters are able to request the correct kind of aggregation from the SDK. (#840)
• The Aggregator.Checkpoint API is renamed to SynchronizedCopy and adds an argument, a different Aggregator into which the copy is stored. (#812)
• The export.Aggregator contract is that Update() and SynchronizedCopy() are synchronized with each other.
  All the aggregation interfaces (Sum, LastValue, ...) are not meant to be synchronized, as the caller is expected to synchronize aggregators at a higher level after the Accumulator.
  Some of the Aggregators used unnecessary locking and that has been cleaned up. (#812)
• Use of metric.Number was replaced by int64 now that we use sync.Mutex in the MinMaxSumCount and Histogram Aggregators. (#812)
• Replace AlwaysParentSample with ParentSample(fallback) to match the OpenTelemetry v0.5.0 specification. (#810)
• Rename sdk/export/metric/aggregator to sdk/export/metric/aggregation. #808
• Send configured headers with every request in the OTLP exporter, instead of just on connection creation. (#806)
• Update error handling for any one off error handlers, replacing, instead, with the global.Handle function. (#791)
• Rename plugin directory to instrumentation to match the OpenTelemetry specification. (#779)
• Makes the argument order to Histogram and DDSketch New() consistent. (#781)

Removed

• Uint64NumberKind and related functions from the API. (#864)
• Context arguments from Aggregator.Checkpoint and Integrator.Process as they were unused. (#803)
• SpanID is no longer included in parameters for sampling decision to match the OpenTelemetry specification. (#775)

Fixed

• Upgrade OTLP exporter to opentelemetry-proto matching the opentelemetry-collector v0.4.0 release. (#866)
• Allow changes to go.sum and go.mod when running dependabot tidy-up. (#871)
• Bump github.com/stretchr/testify from 1.4.0 to 1.6.1. (#824)
• Bump github.com/prometheus/client_golang from 1.7.0 to 1.7.1 in /exporters/metric/prometheus. (#867)
• Bump google.golang.org/grpc from 1.29.1 to 1.30.0 in /exporters/trace/jaeger. (#853)
• Bump google.golang.org/grpc from 1.29.1 to 1.30.0 in /exporters/trace/zipkin. (#854)
• Bumps github.com/golang/protobuf from 1.3.2 to 1.4.2 (#848)
• Bump github.com/stretchr/testify from 1.4.0 to 1.6.1 in /exporters/otlp (#817)
• Bump github.com/golangci/golangci-lint from 1.25.1 to 1.27.0 in /tools (#828)
• Bump github.com/prometheus/client_golang from 1.5.0 to 1.7.0 in /exporters/metric/prometheus (#838)
• Bump github.com/stretchr/testify from 1.4.0 to 1.6.1 in /exporters/trace/jaeger (#829)
• Bump github.com/benbjohnson/clock from 1.0.0 to 1.0.3 (#815)
• Bump github.com/stretchr/testify from 1.4.0 to 1.6.1 in /exporters/trace/zipkin (#823)
• Bump github.com/itchyny/gojq from 0.10.1 to 0.10.3 in /tools (#830)
• Bump github.com/stretchr/testify from 1.4.0 to 1.6.1 in /exporters/metric/prometheus (#822)
• Bump google.golang.org/grpc from 1.27.1 to 1.29.1 in /exporters/trace/zipkin (#820)
• Bump google.golang.org/grpc from 1.27.1 to 1.29.1 in /exporters/trace/jaeger (#831)
• Bump github.com/google/go-cmp from 0.4.0 to 0.5.0 (#836)
• Bump github.com/google/go-cmp from 0.4.0 to 0.5.0 in /exporters/trace/jaeger (#837)
• Bump github.com/google/go-cmp from 0.4.0 to 0.5.0 in /exporters/otlp (#839)
• Bump google.golang.org/api from 0.20.0 to 0.28.0 in /exporters/trace/jaeger (#843)
• Set span status from HTTP status code in the othttp instrumentation. (#832)
• Fixed typo in push controller comment. (#834)
• The Aggregator testing has been updated and cleaned. (#812)
• metric.Number(0) expressions are replaced by 0 where possible. (#812)
• Fixed global handler_test.go test failure. #804
• Fixed BatchSpanProcessor.Shutdown to wait until all spans are processed. (#766)
• Fixed OTLP example's accidental early close of exporter. (#807)
• Ensure zipkin exporter reads and closes response body. (#788)
• Update instrumentation to use api/standard keys instead of custom keys. (#782)
• Clean up tools and RELEASING documentation. (#762)