Prepare release v0.16.0

[Aneurysm9]

0.16.0 - 2020-01-13

Added

• Add the ReadOnlySpan and ReadWriteSpan interfaces to provide better control for accessing span data. (Add RO/RW span interfaces #1360)
• NewGRPCDriver function returns a ProtocolDriver that maintains a single gRPC connection to the collector. (Split connection management away from exporter #1369)
• Added documentation about the project's versioning policy. (Add Versioning Documentation #1388)
• Added NewSplitDriver for OTLP exporter that allows sending traces and metrics to different endpoints. (Add a split protocol driver for otlp exporter #1418)
• Added codeql worfklow to GitHub Actions (Adding Security Workflows to GitHub Actions (1/2): codeql workflow #1428)
• Added Gosec workflow to GitHub Actions (Adding Security Workflows to GitHub Actions (2/2): gosec workflow #1429)
• Add new HTTP driver for OTLP exporter in exporters/otlp/otlphttp. Currently it only supports the binary protobuf payloads. (Move gRPC driver to a subpackage and add an HTTP driver #1420)

Changed

• Rename internal/testing to internal/internaltest. (Rename internal/testing to internal/internaltest #1449)
• Rename export.SpanData to export.SpanSnapshot and use it only for exporting spans. (Add RO/RW span interfaces #1360)
• Store the parent's full SpanContext rather than just its span ID in the span struct. (Add RO/RW span interfaces #1360)
• Improve span duration accuracy. (Add RO/RW span interfaces #1360)
• Migrated CI/CD from CircleCI to GitHub Actions (Migrate CircleCI ci.yml workflow to GitHub Actions #1382)
• Remove duplicate checkout from GitHub Actions workflow (Fix duplicate checkout action in GitHub workflow #1407)
• Metric array aggregator renamed exact to match its aggregation.Kind (Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps #1412)
• Metric exact aggregator includes per-point timestamps (Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps #1412)
• Metric stdout exporter uses MinMaxSumCount aggregator for ValueRecorder instruments (Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps #1412)
• NewExporter from exporters/otlp now takes a ProtocolDriver as a parameter. (Split connection management away from exporter #1369)
• Many OTLP Exporter options became gRPC ProtocolDriver options. (Split connection management away from exporter #1369)
• Unify endpoint API that related to OTel exporter. (Unify endpoint API that related to OTel exporter #1401)
• Optimize metric histogram aggregator to re-use its slice of buckets. (Metric histogram aggregator: Swap in SynchronizedMove to avoid allocations #1435)
• Metric aggregator Count() and histogram Bucket.Counts are consistently uint64. (1430)
• SamplingResult now passed a Tracestate from the parent SpanContext (Add Tracestate into the SamplingResult struct #1432)
• Moved gRPC driver for OTLP exporter to exporters/otlp/otlpgrpc. (Move gRPC driver to a subpackage and add an HTTP driver #1420)
• The TraceContext propagator now correctly propagates TraceState through the SpanContext. (Handle tracestate in TraceContext propagator  #1447)
• Metric Push and Pull Controller components are combined into a single "basic" Controller:
  • WithExporter() and Start() to configure Push behavior
  • Start() is optional; use Collect() and ForEach() for Pull behavior
  • Start() and Stop() accept Context. (Combine the Push and Pull metric controllers #1378)

Removed

• Remove errUninitializedSpan as its only usage is now obsolete. (Add RO/RW span interfaces #1360)
• Remove Metric export functionality related to quantiles and summary data points: this is not specified (Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps #1412)
• Remove DDSketch metric aggregator; our intention is to re-introduce this as an option of the histogram aggregator after new OTLP histogram data types are released (Remove Quantile aggregation, DDSketch aggregator; add Exact timestamps #1412)

Fixed

• BatchSpanProcessor.Shutdown() will now shutdown underlying export.SpanExporter. (Shutdown underlying span exporter while shutting down BatchSpanProcessor #1443)

[codecov]

Codecov Report

Merging #1464 (83e834b) into master (207587b) will increase coverage by 0.0%.
The diff coverage is 0.0%.

@@          Coverage Diff           @@
##           master   #1464   +/-   ##
======================================
  Coverage    78.9%   78.9%           
======================================
  Files         128     128           
  Lines        6672    6672           
======================================
+ Hits         5267    5269    +2     
+ Misses       1149    1148    -1     
+ Partials      256     255    -1     

Impacted Files	Coverage Δ
version.go	0.0% <0.0%> (ø)
sdk/trace/batch_span_processor.go	78.8% <0.0%> (+1.9%)	⬆️

[XSAM]

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