Release prep v1.2.0/v0.25.0

[Aneurysm9]

Changed

• Metric SDK export.ExportKind, export.ExportKindSelector types have been renamed to aggregation.Temporality and aggregation.TemporalitySelector respectively to keep in line with current specification and protocol along with built-in selectors (e.g., aggregation.CumulativeTemporalitySelector, ...). (Metrics: Rename sdk/export/metric.ExportKind to aggregation.Temporality #2274)
• The Metric Exporter interface now requires a TemporalitySelector method instead of an ExportKindSelector. (Metrics: Rename sdk/export/metric.ExportKind to aggregation.Temporality #2274)
• Metrics API cleanup. The metric/sdkapi package has been created to relocate the API-to-SDK interface:
  • The following interface types simply moved from metric to metric/sdkapi: Descriptor, MeterImpl, InstrumentImpl, SyncImpl, BoundSyncImpl, AsyncImpl, AsyncRunner, AsyncSingleRunner, and AsyncBatchRunner
  • The following struct types moved and are replaced with type aliases, since they are exposed to the user: Observation, Measurement.
  • The No-op implementations of sync and async instruments are no longer exported, new functions sdkapi.NewNoopAsyncInstrument() and sdkapi.NewNoopSyncInstrument() are provided instead. (Metrics: Move the non-API types into sdkapi #2271)
• Update the SDK BatchSpanProcessor to export all queued spans when ForceFlush is called. (Guarantee ForceFlush of BatchSpanProcessor will export all ended spans #2080, Empty queued spans when ForceFlush called #2335)

Added

• Add the "go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc".WithGRPCConn option so the exporter can reuse an existing gRPC connection. (allow otlp clients to use existing grpc connection #2002)
• Added a new schema module to help parse Schema Files in OTEP 0152 format. (Add ability to parse Schema files according to OTEP 0152 #2267)
• Added a new MapCarrier to the go.opentelemetry.io/otel/propagation package to hold propagated coss-cutting concerns as a map[string]string held in memory. (Add MapCarrier #2334)

[codecov]

Codecov Report

Merging #2377 (e469448) into main (dc888a9) will increase coverage by 0.0%.
The diff coverage is 100.0%.

@@          Coverage Diff          @@
##            main   #2377   +/-   ##
=====================================
  Coverage   73.8%   73.8%           
=====================================
  Files        175     175           
  Lines      12436   12436           
=====================================
+ Hits        9182    9185    +3     
+ Misses      3017    3015    -2     
+ Partials     237     236    -1     

Impacted Files	Coverage Δ
version.go	100.0% <100.0%> (ø)
...s/otlp/otlptrace/internal/connection/connection.go	16.2% <0.0%> (+1.5%)	⬆️