Unify metric API into the one otel/metric package (#4018)

* Move instrument into metric

* Update metric docs to include instrument

* Update package names

* Update all imports of sdk/metric/instrument

* Rename Option to InstrumentOption

* Deprecate otel/metric/instrument

* Add changelog entry

CHANGELOG.md

@@ -59,6 +59,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Fix a data race in `SpanProcessor` returned by `NewSimpleSpanProcessor` in `go.opentelemetry.io/otel/sdk/trace`. (#3951)
 - Automatically figure out the default aggregation with `aggregation.Default`. (#3967)
 
+### Deprecated
+
+- The `go.opentelemetry.io/otel/metric/instrument` package is deprecated.
+  Use the equivalent types added to `go.opentelemetry.io/otel/metric` instead. (#4018)
+
 ## [1.15.0-rc.2/0.38.0-rc.2] 2023-03-23
 
 This is a release candidate for the v1.15.0/v0.38.0 release.

example/prometheus/main.go

@@ -29,7 +29,6 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/exporters/prometheus"
 	api "go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/metric/instrument"
 	"go.opentelemetry.io/otel/sdk/metric"
 )
 
@@ -50,19 +49,19 @@ func main() {
 	// Start the prometheus HTTP server and pass the exporter Collector to it
 	go serveMetrics()
 
-	opt := instrument.WithAttributes(
+	opt := api.WithAttributes(
 		attribute.Key("A").String("B"),
 		attribute.Key("C").String("D"),
 	)
 
 	// This is the equivalent of prometheus.NewCounterVec
-	counter, err := meter.Float64Counter("foo", instrument.WithDescription("a simple counter"))
+	counter, err := meter.Float64Counter("foo", api.WithDescription("a simple counter"))
 	if err != nil {
 		log.Fatal(err)
 	}
 	counter.Add(ctx, 5, opt)
 
-	gauge, err := meter.Float64ObservableGauge("bar", instrument.WithDescription("a fun little gauge"))
+	gauge, err := meter.Float64ObservableGauge("bar", api.WithDescription("a fun little gauge"))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -76,7 +75,7 @@ func main() {
 	}
 
 	// This is the equivalent of prometheus.NewHistogramVec
-	histogram, err := meter.Float64Histogram("baz", instrument.WithDescription("a very nice histogram"))
+	histogram, err := meter.Float64Histogram("baz", api.WithDescription("a very nice histogram"))
 	if err != nil {
 		log.Fatal(err)
 	}

example/view/main.go

@@ -26,7 +26,7 @@ import (
 
 	"go.opentelemetry.io/otel/attribute"
 	otelprom "go.opentelemetry.io/otel/exporters/prometheus"
-	"go.opentelemetry.io/otel/metric/instrument"
+	api "go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/sdk/instrumentation"
 	"go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/metric/aggregation"
@@ -64,18 +64,18 @@ func main() {
 	// Start the prometheus HTTP server and pass the exporter Collector to it
 	go serveMetrics()
 
-	opt := instrument.WithAttributes(
+	opt := api.WithAttributes(
 		attribute.Key("A").String("B"),
 		attribute.Key("C").String("D"),
 	)
 
-	counter, err := meter.Float64Counter("foo", instrument.WithDescription("a simple counter"))
+	counter, err := meter.Float64Counter("foo", api.WithDescription("a simple counter"))
 	if err != nil {
 		log.Fatal(err)
 	}
 	counter.Add(ctx, 5, opt)
 
-	histogram, err := meter.Float64Histogram("custom_histogram", instrument.WithDescription("a histogram with custom buckets and rename"))
+	histogram, err := meter.Float64Histogram("custom_histogram", api.WithDescription("a histogram with custom buckets and rename"))
 	if err != nil {
 		log.Fatal(err)
 	}