go.opentelemetry.io/otel/metric

Added

• The Prometheus exporter in go.opentelemetry.io/otel/exporters/prometheus registers with a Prometheus registerer on creation. By default, it will register with the default Prometheus registerer. A non-default registerer can be used by passing the WithRegisterer option. (#3239)
• Added the WithAggregationSelector option to the go.opentelemetry.io/otel/exporters/prometheus package to change the default AggregationSelector used. (#3341)
• The Prometheus exporter in go.opentelemetry.io/otel/exporters/prometheus converts the Resource associated with metric exports into a target_info metric. (#3285)

Changed

• The "go.opentelemetry.io/otel/exporters/prometheus".New function is updated to return an error. It will return an error if the exporter fails to register with Prometheus. (#3239)

Fixed

• The URL-encoded values from the OTEL_RESOURCE_ATTRIBUTES environment variable are decoded. (#2963)
• The baggage.NewMember function decodes the value parameter instead of directly using it. This fixes the implementation to be compliant with the W3C specification. (#3226)
• Slice attributes of the attribute package are now comparable based on their value, not instance. (#3108 #3252)
• The Shutdown and ForceFlush methods of the "go.opentelemetry.io/otel/sdk/trace".TraceProvider no longer return an error when no processor is registered. (#3268)
• The Prometheus exporter in go.opentelemetry.io/otel/exporters/prometheus cumulatively sums histogram buckets. (#3281)
• The sum of each histogram data point is now uniquely exported by the go.opentelemetry.io/otel/exporters/otlpmetric exporters. (#3284, #3293)
• Recorded values for asynchronous counters (Counter and UpDownCounter) are interpreted as exact, not incremental, sum values by the metric SDK. (#3350, #3278)
• UpDownCounters are now correctly output as Prometheus gauges in the go.opentelemetry.io/otel/exporters/prometheus exporter. (#3358)
• The Prometheus exporter in go.opentelemetry.io/otel/exporters/prometheus no longer describes the metrics it will send to Prometheus on startup. Instead the exporter is defined as an "unchecked" collector for Prometheus. This fixes the reader is not registered warning currently emitted on startup. (#3291 #3342)
• The go.opentelemetry.io/otel/exporters/prometheus exporter now correctly adds _total suffixes to counter metrics. (#3360)
• The go.opentelemetry.io/otel/exporters/prometheus exporter now adds a unit suffix to metric names. This can be disabled using the WithoutUnits() option added to that package. (#3352)

Added

• Add default User-Agent header to OTLP exporter requests (go.opentelemetry.io/otel/exporters/otlptrace/otlptracegrpc and go.opentelemetry.io/otel/exporters/otlptrace/otlptracehttp). (#3261)

Changed

• span.SetStatus has been updated such that calls that lower the status are now no-ops. (#3214)
• Upgrade golang.org/x/sys/unix from v0.0.0-20210423185535-09eb48e85fd7 to v0.0.0-20220919091848-fb04ddd9f9c8. This addresses GO-2022-0493. (#3235)

Added

• Added an example of using metric views to customize instruments. (#3177)
• Add default User-Agent header to OTLP exporter requests (go.opentelemetry.io/otel/exporters/otlpmetric/otlpmetricgrpc and go.opentelemetry.io/otel/exporters/otlpmetric/otlpmetrichttp). (#3261)

Changed

• Flush pending measurements with the PeriodicReader in the go.opentelemetry.io/otel/sdk/metric when ForceFlush or Shutdown are called. (#3220)
• Update histogram default bounds to match the requirements of the latest specification. (#3222)
• Encode the HTTP status code in the OpenTracing bridge (go.opentelemetry.io/otel/bridge/opentracing) as an integer. (#3265)

Fixed

• Use default view if instrument does not match any registered view of a reader. (#3224, #3237)
• Return the same instrument every time a user makes the exact same instrument creation call. (#3229, #3251)
• Return the existing instrument when a view transforms a creation call to match an existing instrument. (#3240, #3251)
• Log a warning when a conflicting instrument (e.g. description, unit, data-type) is created instead of returning an error. (#3251)
• The OpenCensus bridge no longer sends empty batches of metrics. (#3263)

Changed

• The Prometheus exporter sanitizes OpenTelemetry instrument names when exporting. Invalid characters are replaced with _. (#3212)

Added

• The metric portion of the OpenCensus bridge (go.opentelemetry.io/otel/bridge/opencensus) has been reintroduced. (#3192)
• The OpenCensus bridge example (go.opentelemetry.io/otel/example/opencensus) has been reintroduced. (#3206)

Fixed

• Updated go.mods to point to valid versions of the sdk. (#3216)
• Set the MeterProvider resource on all exported metric data. (#3218)

Changed

• The metric SDK in go.opentelemetry.io/otel/sdk/metric is completely refactored to comply with the OpenTelemetry specification. Please see the package documentation for how the new SDK is initialized and configured. (#3175)
• Update the minimum supported go version to go1.18. Removes support for go1.17 (#3179)

Removed

• The metric portion of the OpenCensus bridge (go.opentelemetry.io/otel/bridge/opencensus) has been removed. A new bridge compliant with the revised metric SDK will be added back in a future release. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/aggregator/aggregatortest package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/aggregator/histogram package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/aggregator/lastvalue package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/aggregator/sum package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/aggregator package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/controller/basic package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/controller/controllertest package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/controller/time package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/export/aggregation package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/export package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/metrictest package is removed. A replacement package that supports the new metric SDK will be added back in a future release. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/number package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/processor/basic package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/processor/processortest package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/processor/reducer package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/registry package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/sdkapi package is removed, see the new metric SDK. (#3175)
• The go.opentelemetry.io/otel/sdk/metric/selector/simple package is removed, see the new metric SDK. (#3175)
• The "go.opentelemetry.io/otel/sdk/metric".ErrUninitializedInstrument variable was removed. (#3175)
• The "go.opentelemetry.io/otel/sdk/metric".ErrBadInstrument variable was removed. (#3175)
• The "go.opentelemetry.io/otel/sdk/metric".Accumulator type was removed, see the MeterProviderin the new metric SDK. (#3175)
• The "go.opentelemetry.io/otel/sdk/metric".NewAccumulator function was removed, see NewMeterProviderin the new metric SDK. (#3175)
• The deprecated "go.opentelemetry.io/otel/sdk/metric".AtomicFieldOffsets function was removed. (#3175)