TUN-8052: Update go to 1.21.5

Also update golang.org/x/net and google.golang.org/grpc to fix vulnerabilities,
although cloudflared is using them in a way that is not exposed to those risks

vendor/go.opentelemetry.io/otel/metric/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
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+
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vendor/go.opentelemetry.io/otel/metric/asyncfloat64.go

@@ -0,0 +1,271 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric/embedded"
+)
+
+// Float64Observable describes a set of instruments used asynchronously to
+// record float64 measurements once per collection cycle. Observations of
+// these instruments are only made within a callback.
+//
+// Warning: Methods may be added to this interface in minor releases.
+type Float64Observable interface {
+	Observable
+
+	float64Observable()
+}
+
+// Float64ObservableCounter is an instrument used to asynchronously record
+// increasing float64 measurements once per collection cycle. Observations are
+// only made within a callback for this instrument. The value observed is
+// assumed the to be the cumulative sum of the count.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for
+// unimplemented methods.
+type Float64ObservableCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64ObservableCounter
+
+	Float64Observable
+}
+
+// Float64ObservableCounterConfig contains options for asynchronous counter
+// instruments that record int64 values.
+type Float64ObservableCounterConfig struct {
+	description string
+	unit        string
+	callbacks   []Float64Callback
+}
+
+// NewFloat64ObservableCounterConfig returns a new
+// [Float64ObservableCounterConfig] with all opts applied.
+func NewFloat64ObservableCounterConfig(opts ...Float64ObservableCounterOption) Float64ObservableCounterConfig {
+	var config Float64ObservableCounterConfig
+	for _, o := range opts {
+		config = o.applyFloat64ObservableCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64ObservableCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64ObservableCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Float64ObservableCounterConfig) Callbacks() []Float64Callback {
+	return c.callbacks
+}
+
+// Float64ObservableCounterOption applies options to a
+// [Float64ObservableCounterConfig]. See [Float64ObservableOption] and
+// [InstrumentOption] for other options that can be used as a
+// Float64ObservableCounterOption.
+type Float64ObservableCounterOption interface {
+	applyFloat64ObservableCounter(Float64ObservableCounterConfig) Float64ObservableCounterConfig
+}
+
+// Float64ObservableUpDownCounter is an instrument used to asynchronously
+// record float64 measurements once per collection cycle. Observations are only
+// made within a callback for this instrument. The value observed is assumed
+// the to be the cumulative sum of the count.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64ObservableUpDownCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64ObservableUpDownCounter
+
+	Float64Observable
+}
+
+// Float64ObservableUpDownCounterConfig contains options for asynchronous
+// counter instruments that record int64 values.
+type Float64ObservableUpDownCounterConfig struct {
+	description string
+	unit        string
+	callbacks   []Float64Callback
+}
+
+// NewFloat64ObservableUpDownCounterConfig returns a new
+// [Float64ObservableUpDownCounterConfig] with all opts applied.
+func NewFloat64ObservableUpDownCounterConfig(opts ...Float64ObservableUpDownCounterOption) Float64ObservableUpDownCounterConfig {
+	var config Float64ObservableUpDownCounterConfig
+	for _, o := range opts {
+		config = o.applyFloat64ObservableUpDownCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64ObservableUpDownCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64ObservableUpDownCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Float64ObservableUpDownCounterConfig) Callbacks() []Float64Callback {
+	return c.callbacks
+}
+
+// Float64ObservableUpDownCounterOption applies options to a
+// [Float64ObservableUpDownCounterConfig]. See [Float64ObservableOption] and
+// [InstrumentOption] for other options that can be used as a
+// Float64ObservableUpDownCounterOption.
+type Float64ObservableUpDownCounterOption interface {
+	applyFloat64ObservableUpDownCounter(Float64ObservableUpDownCounterConfig) Float64ObservableUpDownCounterConfig
+}
+
+// Float64ObservableGauge is an instrument used to asynchronously record
+// instantaneous float64 measurements once per collection cycle. Observations
+// are only made within a callback for this instrument.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64ObservableGauge interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64ObservableGauge
+
+	Float64Observable
+}
+
+// Float64ObservableGaugeConfig contains options for asynchronous counter
+// instruments that record int64 values.
+type Float64ObservableGaugeConfig struct {
+	description string
+	unit        string
+	callbacks   []Float64Callback
+}
+
+// NewFloat64ObservableGaugeConfig returns a new [Float64ObservableGaugeConfig]
+// with all opts applied.
+func NewFloat64ObservableGaugeConfig(opts ...Float64ObservableGaugeOption) Float64ObservableGaugeConfig {
+	var config Float64ObservableGaugeConfig
+	for _, o := range opts {
+		config = o.applyFloat64ObservableGauge(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64ObservableGaugeConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64ObservableGaugeConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Float64ObservableGaugeConfig) Callbacks() []Float64Callback {
+	return c.callbacks
+}
+
+// Float64ObservableGaugeOption applies options to a
+// [Float64ObservableGaugeConfig]. See [Float64ObservableOption] and
+// [InstrumentOption] for other options that can be used as a
+// Float64ObservableGaugeOption.
+type Float64ObservableGaugeOption interface {
+	applyFloat64ObservableGauge(Float64ObservableGaugeConfig) Float64ObservableGaugeConfig
+}
+
+// Float64Observer is a recorder of float64 measurements.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64Observer interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64Observer
+
+	// Observe records the float64 value.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Observe(value float64, options ...ObserveOption)
+}
+
+// Float64Callback is a function registered with a Meter that makes
+// observations for a Float64Observerable instrument it is registered with.
+// Calls to the Float64Observer record measurement values for the
+// Float64Observable.
+//
+// The function needs to complete in a finite amount of time and the deadline
+// of the passed context is expected to be honored.
+//
+// The function needs to make unique observations across all registered
+// Float64Callbacks. Meaning, it should not report measurements with the same
+// attributes as another Float64Callbacks also registered for the same
+// instrument.
+//
+// The function needs to be concurrent safe.
+type Float64Callback func(context.Context, Float64Observer) error
+
+// Float64ObservableOption applies options to float64 Observer instruments.
+type Float64ObservableOption interface {
+	Float64ObservableCounterOption
+	Float64ObservableUpDownCounterOption
+	Float64ObservableGaugeOption
+}
+
+type float64CallbackOpt struct {
+	cback Float64Callback
+}
+
+func (o float64CallbackOpt) applyFloat64ObservableCounter(cfg Float64ObservableCounterConfig) Float64ObservableCounterConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+func (o float64CallbackOpt) applyFloat64ObservableUpDownCounter(cfg Float64ObservableUpDownCounterConfig) Float64ObservableUpDownCounterConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+func (o float64CallbackOpt) applyFloat64ObservableGauge(cfg Float64ObservableGaugeConfig) Float64ObservableGaugeConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+// WithFloat64Callback adds callback to be called for an instrument.
+func WithFloat64Callback(callback Float64Callback) Float64ObservableOption {
+	return float64CallbackOpt{callback}
+}

vendor/go.opentelemetry.io/otel/metric/asyncint64.go

@@ -0,0 +1,269 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric/embedded"
+)
+
+// Int64Observable describes a set of instruments used asynchronously to record
+// int64 measurements once per collection cycle. Observations of these
+// instruments are only made within a callback.
+//
+// Warning: Methods may be added to this interface in minor releases.
+type Int64Observable interface {
+	Observable
+
+	int64Observable()
+}
+
+// Int64ObservableCounter is an instrument used to asynchronously record
+// increasing int64 measurements once per collection cycle. Observations are
+// only made within a callback for this instrument. The value observed is
+// assumed the to be the cumulative sum of the count.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64ObservableCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64ObservableCounter
+
+	Int64Observable
+}
+
+// Int64ObservableCounterConfig contains options for asynchronous counter
+// instruments that record int64 values.
+type Int64ObservableCounterConfig struct {
+	description string
+	unit        string
+	callbacks   []Int64Callback
+}
+
+// NewInt64ObservableCounterConfig returns a new [Int64ObservableCounterConfig]
+// with all opts applied.
+func NewInt64ObservableCounterConfig(opts ...Int64ObservableCounterOption) Int64ObservableCounterConfig {
+	var config Int64ObservableCounterConfig
+	for _, o := range opts {
+		config = o.applyInt64ObservableCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64ObservableCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64ObservableCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Int64ObservableCounterConfig) Callbacks() []Int64Callback {
+	return c.callbacks
+}
+
+// Int64ObservableCounterOption applies options to a
+// [Int64ObservableCounterConfig]. See [Int64ObservableOption] and
+// [InstrumentOption] for other options that can be used as an
+// Int64ObservableCounterOption.
+type Int64ObservableCounterOption interface {
+	applyInt64ObservableCounter(Int64ObservableCounterConfig) Int64ObservableCounterConfig
+}
+
+// Int64ObservableUpDownCounter is an instrument used to asynchronously record
+// int64 measurements once per collection cycle. Observations are only made
+// within a callback for this instrument. The value observed is assumed the to
+// be the cumulative sum of the count.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64ObservableUpDownCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64ObservableUpDownCounter
+
+	Int64Observable
+}
+
+// Int64ObservableUpDownCounterConfig contains options for asynchronous counter
+// instruments that record int64 values.
+type Int64ObservableUpDownCounterConfig struct {
+	description string
+	unit        string
+	callbacks   []Int64Callback
+}
+
+// NewInt64ObservableUpDownCounterConfig returns a new
+// [Int64ObservableUpDownCounterConfig] with all opts applied.
+func NewInt64ObservableUpDownCounterConfig(opts ...Int64ObservableUpDownCounterOption) Int64ObservableUpDownCounterConfig {
+	var config Int64ObservableUpDownCounterConfig
+	for _, o := range opts {
+		config = o.applyInt64ObservableUpDownCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64ObservableUpDownCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64ObservableUpDownCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Int64ObservableUpDownCounterConfig) Callbacks() []Int64Callback {
+	return c.callbacks
+}
+
+// Int64ObservableUpDownCounterOption applies options to a
+// [Int64ObservableUpDownCounterConfig]. See [Int64ObservableOption] and
+// [InstrumentOption] for other options that can be used as an
+// Int64ObservableUpDownCounterOption.
+type Int64ObservableUpDownCounterOption interface {
+	applyInt64ObservableUpDownCounter(Int64ObservableUpDownCounterConfig) Int64ObservableUpDownCounterConfig
+}
+
+// Int64ObservableGauge is an instrument used to asynchronously record
+// instantaneous int64 measurements once per collection cycle. Observations are
+// only made within a callback for this instrument.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64ObservableGauge interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64ObservableGauge
+
+	Int64Observable
+}
+
+// Int64ObservableGaugeConfig contains options for asynchronous counter
+// instruments that record int64 values.
+type Int64ObservableGaugeConfig struct {
+	description string
+	unit        string
+	callbacks   []Int64Callback
+}
+
+// NewInt64ObservableGaugeConfig returns a new [Int64ObservableGaugeConfig]
+// with all opts applied.
+func NewInt64ObservableGaugeConfig(opts ...Int64ObservableGaugeOption) Int64ObservableGaugeConfig {
+	var config Int64ObservableGaugeConfig
+	for _, o := range opts {
+		config = o.applyInt64ObservableGauge(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64ObservableGaugeConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64ObservableGaugeConfig) Unit() string {
+	return c.unit
+}
+
+// Callbacks returns the configured callbacks.
+func (c Int64ObservableGaugeConfig) Callbacks() []Int64Callback {
+	return c.callbacks
+}
+
+// Int64ObservableGaugeOption applies options to a
+// [Int64ObservableGaugeConfig]. See [Int64ObservableOption] and
+// [InstrumentOption] for other options that can be used as an
+// Int64ObservableGaugeOption.
+type Int64ObservableGaugeOption interface {
+	applyInt64ObservableGauge(Int64ObservableGaugeConfig) Int64ObservableGaugeConfig
+}
+
+// Int64Observer is a recorder of int64 measurements.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64Observer interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64Observer
+
+	// Observe records the int64 value.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Observe(value int64, options ...ObserveOption)
+}
+
+// Int64Callback is a function registered with a Meter that makes observations
+// for an Int64Observerable instrument it is registered with. Calls to the
+// Int64Observer record measurement values for the Int64Observable.
+//
+// The function needs to complete in a finite amount of time and the deadline
+// of the passed context is expected to be honored.
+//
+// The function needs to make unique observations across all registered
+// Int64Callbacks. Meaning, it should not report measurements with the same
+// attributes as another Int64Callbacks also registered for the same
+// instrument.
+//
+// The function needs to be concurrent safe.
+type Int64Callback func(context.Context, Int64Observer) error
+
+// Int64ObservableOption applies options to int64 Observer instruments.
+type Int64ObservableOption interface {
+	Int64ObservableCounterOption
+	Int64ObservableUpDownCounterOption
+	Int64ObservableGaugeOption
+}
+
+type int64CallbackOpt struct {
+	cback Int64Callback
+}
+
+func (o int64CallbackOpt) applyInt64ObservableCounter(cfg Int64ObservableCounterConfig) Int64ObservableCounterConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+func (o int64CallbackOpt) applyInt64ObservableUpDownCounter(cfg Int64ObservableUpDownCounterConfig) Int64ObservableUpDownCounterConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+func (o int64CallbackOpt) applyInt64ObservableGauge(cfg Int64ObservableGaugeConfig) Int64ObservableGaugeConfig {
+	cfg.callbacks = append(cfg.callbacks, o.cback)
+	return cfg
+}
+
+// WithInt64Callback adds callback to be called for an instrument.
+func WithInt64Callback(callback Int64Callback) Int64ObservableOption {
+	return int64CallbackOpt{callback}
+}

vendor/go.opentelemetry.io/otel/metric/config.go

@@ -0,0 +1,92 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import "go.opentelemetry.io/otel/attribute"
+
+// MeterConfig contains options for Meters.
+type MeterConfig struct {
+	instrumentationVersion string
+	schemaURL              string
+	attrs                  attribute.Set
+
+	// Ensure forward compatibility by explicitly making this not comparable.
+	noCmp [0]func() //nolint: unused  // This is indeed used.
+}
+
+// InstrumentationVersion returns the version of the library providing
+// instrumentation.
+func (cfg MeterConfig) InstrumentationVersion() string {
+	return cfg.instrumentationVersion
+}
+
+// InstrumentationAttributes returns the attributes associated with the library
+// providing instrumentation.
+func (cfg MeterConfig) InstrumentationAttributes() attribute.Set {
+	return cfg.attrs
+}
+
+// SchemaURL is the schema_url of the library providing instrumentation.
+func (cfg MeterConfig) SchemaURL() string {
+	return cfg.schemaURL
+}
+
+// MeterOption is an interface for applying Meter options.
+type MeterOption interface {
+	// applyMeter is used to set a MeterOption value of a MeterConfig.
+	applyMeter(MeterConfig) MeterConfig
+}
+
+// NewMeterConfig creates a new MeterConfig and applies
+// all the given options.
+func NewMeterConfig(opts ...MeterOption) MeterConfig {
+	var config MeterConfig
+	for _, o := range opts {
+		config = o.applyMeter(config)
+	}
+	return config
+}
+
+type meterOptionFunc func(MeterConfig) MeterConfig
+
+func (fn meterOptionFunc) applyMeter(cfg MeterConfig) MeterConfig {
+	return fn(cfg)
+}
+
+// WithInstrumentationVersion sets the instrumentation version.
+func WithInstrumentationVersion(version string) MeterOption {
+	return meterOptionFunc(func(config MeterConfig) MeterConfig {
+		config.instrumentationVersion = version
+		return config
+	})
+}
+
+// WithInstrumentationAttributes sets the instrumentation attributes.
+//
+// The passed attributes will be de-duplicated.
+func WithInstrumentationAttributes(attr ...attribute.KeyValue) MeterOption {
+	return meterOptionFunc(func(config MeterConfig) MeterConfig {
+		config.attrs = attribute.NewSet(attr...)
+		return config
+	})
+}
+
+// WithSchemaURL sets the schema URL.
+func WithSchemaURL(schemaURL string) MeterOption {
+	return meterOptionFunc(func(config MeterConfig) MeterConfig {
+		config.schemaURL = schemaURL
+		return config
+	})
+}

vendor/go.opentelemetry.io/otel/metric/doc.go

@@ -0,0 +1,170 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*
+Package metric provides the OpenTelemetry API used to measure metrics about
+source code operation.
+
+This API is separate from its implementation so the instrumentation built from
+it is reusable. See [go.opentelemetry.io/otel/sdk/metric] for the official
+OpenTelemetry implementation of this API.
+
+All measurements made with this package are made via instruments. These
+instruments are created by a [Meter] which itself is created by a
+[MeterProvider]. Applications need to accept a [MeterProvider] implementation
+as a starting point when instrumenting. This can be done directly, or by using
+the OpenTelemetry global MeterProvider via [GetMeterProvider]. Using an
+appropriately named [Meter] from the accepted [MeterProvider], instrumentation
+can then be built from the [Meter]'s instruments.
+
+# Instruments
+
+Each instrument is designed to make measurements of a particular type. Broadly,
+all instruments fall into two overlapping logical categories: asynchronous or
+synchronous, and int64 or float64.
+
+All synchronous instruments ([Int64Counter], [Int64UpDownCounter],
+[Int64Histogram], [Float64Counter], [Float64UpDownCounter], and
+[Float64Histogram]) are used to measure the operation and performance of source
+code during the source code execution. These instruments only make measurements
+when the source code they instrument is run.
+
+All asynchronous instruments ([Int64ObservableCounter],
+[Int64ObservableUpDownCounter], [Int64ObservableGauge],
+[Float64ObservableCounter], [Float64ObservableUpDownCounter], and
+[Float64ObservableGauge]) are used to measure metrics outside of the execution
+of source code. They are said to make "observations" via a callback function
+called once every measurement collection cycle.
+
+Each instrument is also grouped by the value type it measures. Either int64 or
+float64. The value being measured will dictate which instrument in these
+categories to use.
+
+Outside of these two broad categories, instruments are described by the
+function they are designed to serve. All Counters ([Int64Counter],
+[Float64Counter], [Int64ObservableCounter], and [Float64ObservableCounter]) are
+designed to measure values that never decrease in value, but instead only
+incrementally increase in value. UpDownCounters ([Int64UpDownCounter],
+[Float64UpDownCounter], [Int64ObservableUpDownCounter], and
+[Float64ObservableUpDownCounter]) on the other hand, are designed to measure
+values that can increase and decrease. When more information needs to be
+conveyed about all the synchronous measurements made during a collection cycle,
+a Histogram ([Int64Histogram] and [Float64Histogram]) should be used. Finally,
+when just the most recent measurement needs to be conveyed about an
+asynchronous measurement, a Gauge ([Int64ObservableGauge] and
+[Float64ObservableGauge]) should be used.
+
+See the [OpenTelemetry documentation] for more information about instruments
+and their intended use.
+
+# Measurements
+
+Measurements are made by recording values and information about the values with
+an instrument. How these measurements are recorded depends on the instrument.
+
+Measurements for synchronous instruments ([Int64Counter], [Int64UpDownCounter],
+[Int64Histogram], [Float64Counter], [Float64UpDownCounter], and
+[Float64Histogram]) are recorded using the instrument methods directly. All
+counter instruments have an Add method that is used to measure an increment
+value, and all histogram instruments have a Record method to measure a data
+point.
+
+Asynchronous instruments ([Int64ObservableCounter],
+[Int64ObservableUpDownCounter], [Int64ObservableGauge],
+[Float64ObservableCounter], [Float64ObservableUpDownCounter], and
+[Float64ObservableGauge]) record measurements within a callback function. The
+callback is registered with the Meter which ensures the callback is called once
+per collection cycle. A callback can be registered two ways: during the
+instrument's creation using an option, or later using the RegisterCallback
+method of the [Meter] that created the instrument.
+
+If the following criteria are met, an option ([WithInt64Callback] or
+[WithFloat64Callback]) can be used during the asynchronous instrument's
+creation to register a callback ([Int64Callback] or [Float64Callback],
+respectively):
+
+  - The measurement process is known when the instrument is created
+  - Only that instrument will make a measurement within the callback
+  - The callback never needs to be unregistered
+
+If the criteria are not met, use the RegisterCallback method of the [Meter] that
+created the instrument to register a [Callback].
+
+# API Implementations
+
+This package does not conform to the standard Go versioning policy, all of its
+interfaces may have methods added to them without a package major version bump.
+This non-standard API evolution could surprise an uninformed implementation
+author. They could unknowingly build their implementation in a way that would
+result in a runtime panic for their users that update to the new API.
+
+The API is designed to help inform an instrumentation author about this
+non-standard API evolution. It requires them to choose a default behavior for
+unimplemented interface methods. There are three behavior choices they can
+make:
+
+  - Compilation failure
+  - Panic
+  - Default to another implementation
+
+All interfaces in this API embed a corresponding interface from
+[go.opentelemetry.io/otel/metric/embedded]. If an author wants the default
+behavior of their implementations to be a compilation failure, signaling to
+their users they need to update to the latest version of that implementation,
+they need to embed the corresponding interface from
+[go.opentelemetry.io/otel/metric/embedded] in their implementation. For
+example,
+
+	import "go.opentelemetry.io/otel/metric/embedded"
+
+	type MeterProvider struct {
+		embedded.MeterProvider
+		// ...
+	}
+
+If an author wants the default behavior of their implementations to a panic,
+they need to embed the API interface directly.
+
+	import "go.opentelemetry.io/otel/metric"
+
+	type MeterProvider struct {
+		metric.MeterProvider
+		// ...
+	}
+
+This is not a recommended behavior as it could lead to publishing packages that
+contain runtime panics when users update other package that use newer versions
+of [go.opentelemetry.io/otel/metric].
+
+Finally, an author can embed another implementation in theirs. The embedded
+implementation will be used for methods not defined by the author. For example,
+an author who wants to default to silently dropping the call can use
+[go.opentelemetry.io/otel/metric/noop]:
+
+	import "go.opentelemetry.io/otel/metric/noop"
+
+	type MeterProvider struct {
+		noop.MeterProvider
+		// ...
+	}
+
+It is strongly recommended that authors only embed
+[go.opentelemetry.io/otel/metric/noop] if they choose this default behavior.
+That implementation is the only one OpenTelemetry authors can guarantee will
+fully implement all the API interfaces when a user updates their API.
+
+[OpenTelemetry documentation]: https://opentelemetry.io/docs/concepts/signals/metrics/
+[GetMeterProvider]: https://pkg.go.dev/go.opentelemetry.io/otel#GetMeterProvider
+*/
+package metric // import "go.opentelemetry.io/otel/metric"

vendor/go.opentelemetry.io/otel/metric/embedded/embedded.go

@@ -0,0 +1,234 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package embedded provides interfaces embedded within the [OpenTelemetry
+// metric API].
+//
+// Implementers of the [OpenTelemetry metric API] can embed the relevant type
+// from this package into their implementation directly. Doing so will result
+// in a compilation error for users when the [OpenTelemetry metric API] is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+//
+// [OpenTelemetry metric API]: https://pkg.go.dev/go.opentelemetry.io/otel/metric
+package embedded // import "go.opentelemetry.io/otel/metric/embedded"
+
+// MeterProvider is embedded in
+// [go.opentelemetry.io/otel/metric.MeterProvider].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.MeterProvider] if you want users to
+// experience a compilation error, signaling they need to update to your latest
+// implementation, when the [go.opentelemetry.io/otel/metric.MeterProvider]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type MeterProvider interface{ meterProvider() }
+
+// Meter is embedded in [go.opentelemetry.io/otel/metric.Meter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Meter] if you want users to experience a
+// compilation error, signaling they need to update to your latest
+// implementation, when the [go.opentelemetry.io/otel/metric.Meter] interface
+// is extended (which is something that can happen without a major version bump
+// of the API package).
+type Meter interface{ meter() }
+
+// Float64Observer is embedded in
+// [go.opentelemetry.io/otel/metric.Float64Observer].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64Observer] if you want
+// users to experience a compilation error, signaling they need to update to
+// your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64Observer] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Float64Observer interface{ float64Observer() }
+
+// Int64Observer is embedded in
+// [go.opentelemetry.io/otel/metric.Int64Observer].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64Observer] if you want users
+// to experience a compilation error, signaling they need to update to your
+// latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64Observer] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Int64Observer interface{ int64Observer() }
+
+// Observer is embedded in [go.opentelemetry.io/otel/metric.Observer].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Observer] if you want users to experience a
+// compilation error, signaling they need to update to your latest
+// implementation, when the [go.opentelemetry.io/otel/metric.Observer]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Observer interface{ observer() }
+
+// Registration is embedded in [go.opentelemetry.io/otel/metric.Registration].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Registration] if you want users to
+// experience a compilation error, signaling they need to update to your latest
+// implementation, when the [go.opentelemetry.io/otel/metric.Registration]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Registration interface{ registration() }
+
+// Float64Counter is embedded in
+// [go.opentelemetry.io/otel/metric.Float64Counter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64Counter] if you want
+// users to experience a compilation error, signaling they need to update to
+// your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64Counter] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Float64Counter interface{ float64Counter() }
+
+// Float64Histogram is embedded in
+// [go.opentelemetry.io/otel/metric.Float64Histogram].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64Histogram] if you want
+// users to experience a compilation error, signaling they need to update to
+// your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64Histogram] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Float64Histogram interface{ float64Histogram() }
+
+// Float64ObservableCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Float64ObservableCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64ObservableCounter] if you
+// want users to experience a compilation error, signaling they need to update
+// to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64ObservableCounter]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Float64ObservableCounter interface{ float64ObservableCounter() }
+
+// Float64ObservableGauge is embedded in
+// [go.opentelemetry.io/otel/metric.Float64ObservableGauge].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64ObservableGauge] if you
+// want users to experience a compilation error, signaling they need to update
+// to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64ObservableGauge]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Float64ObservableGauge interface{ float64ObservableGauge() }
+
+// Float64ObservableUpDownCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Float64ObservableUpDownCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64ObservableUpDownCounter]
+// if you want users to experience a compilation error, signaling they need to
+// update to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64ObservableUpDownCounter]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Float64ObservableUpDownCounter interface{ float64ObservableUpDownCounter() }
+
+// Float64UpDownCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Float64UpDownCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Float64UpDownCounter] if you
+// want users to experience a compilation error, signaling they need to update
+// to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Float64UpDownCounter] interface
+// is extended (which is something that can happen without a major version bump
+// of the API package).
+type Float64UpDownCounter interface{ float64UpDownCounter() }
+
+// Int64Counter is embedded in
+// [go.opentelemetry.io/otel/metric.Int64Counter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64Counter] if you want users
+// to experience a compilation error, signaling they need to update to your
+// latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64Counter] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Int64Counter interface{ int64Counter() }
+
+// Int64Histogram is embedded in
+// [go.opentelemetry.io/otel/metric.Int64Histogram].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64Histogram] if you want
+// users to experience a compilation error, signaling they need to update to
+// your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64Histogram] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Int64Histogram interface{ int64Histogram() }
+
+// Int64ObservableCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Int64ObservableCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64ObservableCounter] if you
+// want users to experience a compilation error, signaling they need to update
+// to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64ObservableCounter]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Int64ObservableCounter interface{ int64ObservableCounter() }
+
+// Int64ObservableGauge is embedded in
+// [go.opentelemetry.io/otel/metric.Int64ObservableGauge].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64ObservableGauge] if you
+// want users to experience a compilation error, signaling they need to update
+// to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64ObservableGauge] interface
+// is extended (which is something that can happen without a major version bump
+// of the API package).
+type Int64ObservableGauge interface{ int64ObservableGauge() }
+
+// Int64ObservableUpDownCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Int64ObservableUpDownCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64ObservableUpDownCounter] if
+// you want users to experience a compilation error, signaling they need to
+// update to your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64ObservableUpDownCounter]
+// interface is extended (which is something that can happen without a major
+// version bump of the API package).
+type Int64ObservableUpDownCounter interface{ int64ObservableUpDownCounter() }
+
+// Int64UpDownCounter is embedded in
+// [go.opentelemetry.io/otel/metric.Int64UpDownCounter].
+//
+// Embed this interface in your implementation of the
+// [go.opentelemetry.io/otel/metric.Int64UpDownCounter] if you want
+// users to experience a compilation error, signaling they need to update to
+// your latest implementation, when the
+// [go.opentelemetry.io/otel/metric.Int64UpDownCounter] interface is
+// extended (which is something that can happen without a major version bump of
+// the API package).
+type Int64UpDownCounter interface{ int64UpDownCounter() }

vendor/go.opentelemetry.io/otel/metric/instrument.go

@@ -0,0 +1,357 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import "go.opentelemetry.io/otel/attribute"
+
+// Observable is used as a grouping mechanism for all instruments that are
+// updated within a Callback.
+type Observable interface {
+	observable()
+}
+
+// InstrumentOption applies options to all instruments.
+type InstrumentOption interface {
+	Int64CounterOption
+	Int64UpDownCounterOption
+	Int64HistogramOption
+	Int64ObservableCounterOption
+	Int64ObservableUpDownCounterOption
+	Int64ObservableGaugeOption
+
+	Float64CounterOption
+	Float64UpDownCounterOption
+	Float64HistogramOption
+	Float64ObservableCounterOption
+	Float64ObservableUpDownCounterOption
+	Float64ObservableGaugeOption
+}
+
+// HistogramOption applies options to histogram instruments.
+type HistogramOption interface {
+	Int64HistogramOption
+	Float64HistogramOption
+}
+
+type descOpt string
+
+func (o descOpt) applyFloat64Counter(c Float64CounterConfig) Float64CounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyFloat64UpDownCounter(c Float64UpDownCounterConfig) Float64UpDownCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyFloat64Histogram(c Float64HistogramConfig) Float64HistogramConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyFloat64ObservableCounter(c Float64ObservableCounterConfig) Float64ObservableCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyFloat64ObservableUpDownCounter(c Float64ObservableUpDownCounterConfig) Float64ObservableUpDownCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyFloat64ObservableGauge(c Float64ObservableGaugeConfig) Float64ObservableGaugeConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64Counter(c Int64CounterConfig) Int64CounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64UpDownCounter(c Int64UpDownCounterConfig) Int64UpDownCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64Histogram(c Int64HistogramConfig) Int64HistogramConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64ObservableCounter(c Int64ObservableCounterConfig) Int64ObservableCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64ObservableUpDownCounter(c Int64ObservableUpDownCounterConfig) Int64ObservableUpDownCounterConfig {
+	c.description = string(o)
+	return c
+}
+
+func (o descOpt) applyInt64ObservableGauge(c Int64ObservableGaugeConfig) Int64ObservableGaugeConfig {
+	c.description = string(o)
+	return c
+}
+
+// WithDescription sets the instrument description.
+func WithDescription(desc string) InstrumentOption { return descOpt(desc) }
+
+type unitOpt string
+
+func (o unitOpt) applyFloat64Counter(c Float64CounterConfig) Float64CounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyFloat64UpDownCounter(c Float64UpDownCounterConfig) Float64UpDownCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyFloat64Histogram(c Float64HistogramConfig) Float64HistogramConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyFloat64ObservableCounter(c Float64ObservableCounterConfig) Float64ObservableCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyFloat64ObservableUpDownCounter(c Float64ObservableUpDownCounterConfig) Float64ObservableUpDownCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyFloat64ObservableGauge(c Float64ObservableGaugeConfig) Float64ObservableGaugeConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64Counter(c Int64CounterConfig) Int64CounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64UpDownCounter(c Int64UpDownCounterConfig) Int64UpDownCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64Histogram(c Int64HistogramConfig) Int64HistogramConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64ObservableCounter(c Int64ObservableCounterConfig) Int64ObservableCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64ObservableUpDownCounter(c Int64ObservableUpDownCounterConfig) Int64ObservableUpDownCounterConfig {
+	c.unit = string(o)
+	return c
+}
+
+func (o unitOpt) applyInt64ObservableGauge(c Int64ObservableGaugeConfig) Int64ObservableGaugeConfig {
+	c.unit = string(o)
+	return c
+}
+
+// WithUnit sets the instrument unit.
+//
+// The unit u should be defined using the appropriate [UCUM](https://ucum.org) case-sensitive code.
+func WithUnit(u string) InstrumentOption { return unitOpt(u) }
+
+// WithExplicitBucketBoundaries sets the instrument explicit bucket boundaries.
+//
+// This option is considered "advisory", and may be ignored by API implementations.
+func WithExplicitBucketBoundaries(bounds ...float64) HistogramOption { return bucketOpt(bounds) }
+
+type bucketOpt []float64
+
+func (o bucketOpt) applyFloat64Histogram(c Float64HistogramConfig) Float64HistogramConfig {
+	c.explicitBucketBoundaries = o
+	return c
+}
+
+func (o bucketOpt) applyInt64Histogram(c Int64HistogramConfig) Int64HistogramConfig {
+	c.explicitBucketBoundaries = o
+	return c
+}
+
+// AddOption applies options to an addition measurement. See
+// [MeasurementOption] for other options that can be used as an AddOption.
+type AddOption interface {
+	applyAdd(AddConfig) AddConfig
+}
+
+// AddConfig contains options for an addition measurement.
+type AddConfig struct {
+	attrs attribute.Set
+}
+
+// NewAddConfig returns a new [AddConfig] with all opts applied.
+func NewAddConfig(opts []AddOption) AddConfig {
+	config := AddConfig{attrs: *attribute.EmptySet()}
+	for _, o := range opts {
+		config = o.applyAdd(config)
+	}
+	return config
+}
+
+// Attributes returns the configured attribute set.
+func (c AddConfig) Attributes() attribute.Set {
+	return c.attrs
+}
+
+// RecordOption applies options to an addition measurement. See
+// [MeasurementOption] for other options that can be used as a RecordOption.
+type RecordOption interface {
+	applyRecord(RecordConfig) RecordConfig
+}
+
+// RecordConfig contains options for a recorded measurement.
+type RecordConfig struct {
+	attrs attribute.Set
+}
+
+// NewRecordConfig returns a new [RecordConfig] with all opts applied.
+func NewRecordConfig(opts []RecordOption) RecordConfig {
+	config := RecordConfig{attrs: *attribute.EmptySet()}
+	for _, o := range opts {
+		config = o.applyRecord(config)
+	}
+	return config
+}
+
+// Attributes returns the configured attribute set.
+func (c RecordConfig) Attributes() attribute.Set {
+	return c.attrs
+}
+
+// ObserveOption applies options to an addition measurement. See
+// [MeasurementOption] for other options that can be used as a ObserveOption.
+type ObserveOption interface {
+	applyObserve(ObserveConfig) ObserveConfig
+}
+
+// ObserveConfig contains options for an observed measurement.
+type ObserveConfig struct {
+	attrs attribute.Set
+}
+
+// NewObserveConfig returns a new [ObserveConfig] with all opts applied.
+func NewObserveConfig(opts []ObserveOption) ObserveConfig {
+	config := ObserveConfig{attrs: *attribute.EmptySet()}
+	for _, o := range opts {
+		config = o.applyObserve(config)
+	}
+	return config
+}
+
+// Attributes returns the configured attribute set.
+func (c ObserveConfig) Attributes() attribute.Set {
+	return c.attrs
+}
+
+// MeasurementOption applies options to all instrument measurement.
+type MeasurementOption interface {
+	AddOption
+	RecordOption
+	ObserveOption
+}
+
+type attrOpt struct {
+	set attribute.Set
+}
+
+// mergeSets returns the union of keys between a and b. Any duplicate keys will
+// use the value associated with b.
+func mergeSets(a, b attribute.Set) attribute.Set {
+	// NewMergeIterator uses the first value for any duplicates.
+	iter := attribute.NewMergeIterator(&b, &a)
+	merged := make([]attribute.KeyValue, 0, a.Len()+b.Len())
+	for iter.Next() {
+		merged = append(merged, iter.Attribute())
+	}
+	return attribute.NewSet(merged...)
+}
+
+func (o attrOpt) applyAdd(c AddConfig) AddConfig {
+	switch {
+	case o.set.Len() == 0:
+	case c.attrs.Len() == 0:
+		c.attrs = o.set
+	default:
+		c.attrs = mergeSets(c.attrs, o.set)
+	}
+	return c
+}
+
+func (o attrOpt) applyRecord(c RecordConfig) RecordConfig {
+	switch {
+	case o.set.Len() == 0:
+	case c.attrs.Len() == 0:
+		c.attrs = o.set
+	default:
+		c.attrs = mergeSets(c.attrs, o.set)
+	}
+	return c
+}
+
+func (o attrOpt) applyObserve(c ObserveConfig) ObserveConfig {
+	switch {
+	case o.set.Len() == 0:
+	case c.attrs.Len() == 0:
+		c.attrs = o.set
+	default:
+		c.attrs = mergeSets(c.attrs, o.set)
+	}
+	return c
+}
+
+// WithAttributeSet sets the attribute Set associated with a measurement is
+// made with.
+//
+// If multiple WithAttributeSet or WithAttributes options are passed the
+// attributes will be merged together in the order they are passed. Attributes
+// with duplicate keys will use the last value passed.
+func WithAttributeSet(attributes attribute.Set) MeasurementOption {
+	return attrOpt{set: attributes}
+}
+
+// WithAttributes converts attributes into an attribute Set and sets the Set to
+// be associated with a measurement. This is shorthand for:
+//
+//	cp := make([]attribute.KeyValue, len(attributes))
+//	copy(cp, attributes)
+//	WithAttributes(attribute.NewSet(cp...))
+//
+// [attribute.NewSet] may modify the passed attributes so this will make a copy
+// of attributes before creating a set in order to ensure this function is
+// concurrent safe. This makes this option function less optimized in
+// comparison to [WithAttributeSet]. Therefore, [WithAttributeSet] should be
+// preferred for performance sensitive code.
+//
+// See [WithAttributeSet] for information about how multiple WithAttributes are
+// merged.
+func WithAttributes(attributes ...attribute.KeyValue) MeasurementOption {
+	cp := make([]attribute.KeyValue, len(attributes))
+	copy(cp, attributes)
+	return attrOpt{set: attribute.NewSet(cp...)}
+}

vendor/go.opentelemetry.io/otel/metric/meter.go

@@ -0,0 +1,212 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric/embedded"
+)
+
+// MeterProvider provides access to named Meter instances, for instrumenting
+// an application or package.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type MeterProvider interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.MeterProvider
+
+	// Meter returns a new Meter with the provided name and configuration.
+	//
+	// A Meter should be scoped at most to a single package. The name needs to
+	// be unique so it does not collide with other names used by
+	// an application, nor other applications. To achieve this, the import path
+	// of the instrumentation package is recommended to be used as name.
+	//
+	// If the name is empty, then an implementation defined default name will
+	// be used instead.
+	Meter(name string, opts ...MeterOption) Meter
+}
+
+// Meter provides access to instrument instances for recording metrics.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Meter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Meter
+
+	// Int64Counter returns a new Int64Counter instrument identified by name
+	// and configured with options. The instrument is used to synchronously
+	// record increasing int64 measurements during a computational operation.
+	Int64Counter(name string, options ...Int64CounterOption) (Int64Counter, error)
+	// Int64UpDownCounter returns a new Int64UpDownCounter instrument
+	// identified by name and configured with options. The instrument is used
+	// to synchronously record int64 measurements during a computational
+	// operation.
+	Int64UpDownCounter(name string, options ...Int64UpDownCounterOption) (Int64UpDownCounter, error)
+	// Int64Histogram returns a new Int64Histogram instrument identified by
+	// name and configured with options. The instrument is used to
+	// synchronously record the distribution of int64 measurements during a
+	// computational operation.
+	Int64Histogram(name string, options ...Int64HistogramOption) (Int64Histogram, error)
+	// Int64ObservableCounter returns a new Int64ObservableCounter identified
+	// by name and configured with options. The instrument is used to
+	// asynchronously record increasing int64 measurements once per a
+	// measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithInt64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Int64ObservableCounter(name string, options ...Int64ObservableCounterOption) (Int64ObservableCounter, error)
+	// Int64ObservableUpDownCounter returns a new Int64ObservableUpDownCounter
+	// instrument identified by name and configured with options. The
+	// instrument is used to asynchronously record int64 measurements once per
+	// a measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithInt64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Int64ObservableUpDownCounter(name string, options ...Int64ObservableUpDownCounterOption) (Int64ObservableUpDownCounter, error)
+	// Int64ObservableGauge returns a new Int64ObservableGauge instrument
+	// identified by name and configured with options. The instrument is used
+	// to asynchronously record instantaneous int64 measurements once per a
+	// measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithInt64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Int64ObservableGauge(name string, options ...Int64ObservableGaugeOption) (Int64ObservableGauge, error)
+
+	// Float64Counter returns a new Float64Counter instrument identified by
+	// name and configured with options. The instrument is used to
+	// synchronously record increasing float64 measurements during a
+	// computational operation.
+	Float64Counter(name string, options ...Float64CounterOption) (Float64Counter, error)
+	// Float64UpDownCounter returns a new Float64UpDownCounter instrument
+	// identified by name and configured with options. The instrument is used
+	// to synchronously record float64 measurements during a computational
+	// operation.
+	Float64UpDownCounter(name string, options ...Float64UpDownCounterOption) (Float64UpDownCounter, error)
+	// Float64Histogram returns a new Float64Histogram instrument identified by
+	// name and configured with options. The instrument is used to
+	// synchronously record the distribution of float64 measurements during a
+	// computational operation.
+	Float64Histogram(name string, options ...Float64HistogramOption) (Float64Histogram, error)
+	// Float64ObservableCounter returns a new Float64ObservableCounter
+	// instrument identified by name and configured with options. The
+	// instrument is used to asynchronously record increasing float64
+	// measurements once per a measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithFloat64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Float64ObservableCounter(name string, options ...Float64ObservableCounterOption) (Float64ObservableCounter, error)
+	// Float64ObservableUpDownCounter returns a new
+	// Float64ObservableUpDownCounter instrument identified by name and
+	// configured with options. The instrument is used to asynchronously record
+	// float64 measurements once per a measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithFloat64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Float64ObservableUpDownCounter(name string, options ...Float64ObservableUpDownCounterOption) (Float64ObservableUpDownCounter, error)
+	// Float64ObservableGauge returns a new Float64ObservableGauge instrument
+	// identified by name and configured with options. The instrument is used
+	// to asynchronously record instantaneous float64 measurements once per a
+	// measurement collection cycle.
+	//
+	// Measurements for the returned instrument are made via a callback. Use
+	// the WithFloat64Callback option to register the callback here, or use the
+	// RegisterCallback method of this Meter to register one later. See the
+	// Measurements section of the package documentation for more information.
+	Float64ObservableGauge(name string, options ...Float64ObservableGaugeOption) (Float64ObservableGauge, error)
+
+	// RegisterCallback registers f to be called during the collection of a
+	// measurement cycle.
+	//
+	// If Unregister of the returned Registration is called, f needs to be
+	// unregistered and not called during collection.
+	//
+	// The instruments f is registered with are the only instruments that f may
+	// observe values for.
+	//
+	// If no instruments are passed, f should not be registered nor called
+	// during collection.
+	//
+	// The function f needs to be concurrent safe.
+	RegisterCallback(f Callback, instruments ...Observable) (Registration, error)
+}
+
+// Callback is a function registered with a Meter that makes observations for
+// the set of instruments it is registered with. The Observer parameter is used
+// to record measurement observations for these instruments.
+//
+// The function needs to complete in a finite amount of time and the deadline
+// of the passed context is expected to be honored.
+//
+// The function needs to make unique observations across all registered
+// Callbacks. Meaning, it should not report measurements for an instrument with
+// the same attributes as another Callback will report.
+//
+// The function needs to be concurrent safe.
+type Callback func(context.Context, Observer) error
+
+// Observer records measurements for multiple instruments in a Callback.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Observer interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Observer
+
+	// ObserveFloat64 records the float64 value for obsrv.
+	ObserveFloat64(obsrv Float64Observable, value float64, opts ...ObserveOption)
+	// ObserveInt64 records the int64 value for obsrv.
+	ObserveInt64(obsrv Int64Observable, value int64, opts ...ObserveOption)
+}
+
+// Registration is an token representing the unique registration of a callback
+// for a set of instruments with a Meter.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Registration interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Registration
+
+	// Unregister removes the callback registration from a Meter.
+	//
+	// This method needs to be idempotent and concurrent safe.
+	Unregister() error
+}

vendor/go.opentelemetry.io/otel/metric/syncfloat64.go

@@ -0,0 +1,185 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric/embedded"
+)
+
+// Float64Counter is an instrument that records increasing float64 values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64Counter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64Counter
+
+	// Add records a change to the counter.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Add(ctx context.Context, incr float64, options ...AddOption)
+}
+
+// Float64CounterConfig contains options for synchronous counter instruments that
+// record int64 values.
+type Float64CounterConfig struct {
+	description string
+	unit        string
+}
+
+// NewFloat64CounterConfig returns a new [Float64CounterConfig] with all opts
+// applied.
+func NewFloat64CounterConfig(opts ...Float64CounterOption) Float64CounterConfig {
+	var config Float64CounterConfig
+	for _, o := range opts {
+		config = o.applyFloat64Counter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64CounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64CounterConfig) Unit() string {
+	return c.unit
+}
+
+// Float64CounterOption applies options to a [Float64CounterConfig]. See
+// [InstrumentOption] for other options that can be used as a
+// Float64CounterOption.
+type Float64CounterOption interface {
+	applyFloat64Counter(Float64CounterConfig) Float64CounterConfig
+}
+
+// Float64UpDownCounter is an instrument that records increasing or decreasing
+// float64 values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64UpDownCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64UpDownCounter
+
+	// Add records a change to the counter.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Add(ctx context.Context, incr float64, options ...AddOption)
+}
+
+// Float64UpDownCounterConfig contains options for synchronous counter
+// instruments that record int64 values.
+type Float64UpDownCounterConfig struct {
+	description string
+	unit        string
+}
+
+// NewFloat64UpDownCounterConfig returns a new [Float64UpDownCounterConfig]
+// with all opts applied.
+func NewFloat64UpDownCounterConfig(opts ...Float64UpDownCounterOption) Float64UpDownCounterConfig {
+	var config Float64UpDownCounterConfig
+	for _, o := range opts {
+		config = o.applyFloat64UpDownCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64UpDownCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64UpDownCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Float64UpDownCounterOption applies options to a
+// [Float64UpDownCounterConfig]. See [InstrumentOption] for other options that
+// can be used as a Float64UpDownCounterOption.
+type Float64UpDownCounterOption interface {
+	applyFloat64UpDownCounter(Float64UpDownCounterConfig) Float64UpDownCounterConfig
+}
+
+// Float64Histogram is an instrument that records a distribution of float64
+// values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Float64Histogram interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Float64Histogram
+
+	// Record adds an additional value to the distribution.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Record(ctx context.Context, incr float64, options ...RecordOption)
+}
+
+// Float64HistogramConfig contains options for synchronous counter instruments
+// that record int64 values.
+type Float64HistogramConfig struct {
+	description              string
+	unit                     string
+	explicitBucketBoundaries []float64
+}
+
+// NewFloat64HistogramConfig returns a new [Float64HistogramConfig] with all
+// opts applied.
+func NewFloat64HistogramConfig(opts ...Float64HistogramOption) Float64HistogramConfig {
+	var config Float64HistogramConfig
+	for _, o := range opts {
+		config = o.applyFloat64Histogram(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Float64HistogramConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Float64HistogramConfig) Unit() string {
+	return c.unit
+}
+
+// ExplicitBucketBoundaries returns the configured explicit bucket boundaries.
+func (c Float64HistogramConfig) ExplicitBucketBoundaries() []float64 {
+	return c.explicitBucketBoundaries
+}
+
+// Float64HistogramOption applies options to a [Float64HistogramConfig]. See
+// [InstrumentOption] for other options that can be used as a
+// Float64HistogramOption.
+type Float64HistogramOption interface {
+	applyFloat64Histogram(Float64HistogramConfig) Float64HistogramConfig
+}

vendor/go.opentelemetry.io/otel/metric/syncint64.go

@@ -0,0 +1,185 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metric // import "go.opentelemetry.io/otel/metric"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/metric/embedded"
+)
+
+// Int64Counter is an instrument that records increasing int64 values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64Counter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64Counter
+
+	// Add records a change to the counter.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Add(ctx context.Context, incr int64, options ...AddOption)
+}
+
+// Int64CounterConfig contains options for synchronous counter instruments that
+// record int64 values.
+type Int64CounterConfig struct {
+	description string
+	unit        string
+}
+
+// NewInt64CounterConfig returns a new [Int64CounterConfig] with all opts
+// applied.
+func NewInt64CounterConfig(opts ...Int64CounterOption) Int64CounterConfig {
+	var config Int64CounterConfig
+	for _, o := range opts {
+		config = o.applyInt64Counter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64CounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64CounterConfig) Unit() string {
+	return c.unit
+}
+
+// Int64CounterOption applies options to a [Int64CounterConfig]. See
+// [InstrumentOption] for other options that can be used as an
+// Int64CounterOption.
+type Int64CounterOption interface {
+	applyInt64Counter(Int64CounterConfig) Int64CounterConfig
+}
+
+// Int64UpDownCounter is an instrument that records increasing or decreasing
+// int64 values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64UpDownCounter interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64UpDownCounter
+
+	// Add records a change to the counter.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Add(ctx context.Context, incr int64, options ...AddOption)
+}
+
+// Int64UpDownCounterConfig contains options for synchronous counter
+// instruments that record int64 values.
+type Int64UpDownCounterConfig struct {
+	description string
+	unit        string
+}
+
+// NewInt64UpDownCounterConfig returns a new [Int64UpDownCounterConfig] with
+// all opts applied.
+func NewInt64UpDownCounterConfig(opts ...Int64UpDownCounterOption) Int64UpDownCounterConfig {
+	var config Int64UpDownCounterConfig
+	for _, o := range opts {
+		config = o.applyInt64UpDownCounter(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64UpDownCounterConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64UpDownCounterConfig) Unit() string {
+	return c.unit
+}
+
+// Int64UpDownCounterOption applies options to a [Int64UpDownCounterConfig].
+// See [InstrumentOption] for other options that can be used as an
+// Int64UpDownCounterOption.
+type Int64UpDownCounterOption interface {
+	applyInt64UpDownCounter(Int64UpDownCounterConfig) Int64UpDownCounterConfig
+}
+
+// Int64Histogram is an instrument that records a distribution of int64
+// values.
+//
+// Warning: Methods may be added to this interface in minor releases. See
+// package documentation on API implementation for information on how to set
+// default behavior for unimplemented methods.
+type Int64Histogram interface {
+	// Users of the interface can ignore this. This embedded type is only used
+	// by implementations of this interface. See the "API Implementations"
+	// section of the package documentation for more information.
+	embedded.Int64Histogram
+
+	// Record adds an additional value to the distribution.
+	//
+	// Use the WithAttributeSet (or, if performance is not a concern,
+	// the WithAttributes) option to include measurement attributes.
+	Record(ctx context.Context, incr int64, options ...RecordOption)
+}
+
+// Int64HistogramConfig contains options for synchronous counter instruments
+// that record int64 values.
+type Int64HistogramConfig struct {
+	description              string
+	unit                     string
+	explicitBucketBoundaries []float64
+}
+
+// NewInt64HistogramConfig returns a new [Int64HistogramConfig] with all opts
+// applied.
+func NewInt64HistogramConfig(opts ...Int64HistogramOption) Int64HistogramConfig {
+	var config Int64HistogramConfig
+	for _, o := range opts {
+		config = o.applyInt64Histogram(config)
+	}
+	return config
+}
+
+// Description returns the configured description.
+func (c Int64HistogramConfig) Description() string {
+	return c.description
+}
+
+// Unit returns the configured unit.
+func (c Int64HistogramConfig) Unit() string {
+	return c.unit
+}
+
+// ExplicitBucketBoundaries returns the configured explicit bucket boundaries.
+func (c Int64HistogramConfig) ExplicitBucketBoundaries() []float64 {
+	return c.explicitBucketBoundaries
+}
+
+// Int64HistogramOption applies options to a [Int64HistogramConfig]. See
+// [InstrumentOption] for other options that can be used as an
+// Int64HistogramOption.
+type Int64HistogramOption interface {
+	applyInt64Histogram(Int64HistogramConfig) Int64HistogramConfig
+}