// Copyright The OpenTelemetry Authors // SPDX-License-Identifier: Apache-2.0 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) // Int64Gauge returns a new Int64Gauge instrument identified by name and // configured with options. The instrument is used to synchronously record // instantaneous int64 measurements during a computational operation. Int64Gauge(name string, options ...Int64GaugeOption) (Int64Gauge, 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) // Float64Gauge returns a new Float64Gauge instrument identified by name and // configured with options. The instrument is used to synchronously record // instantaneous float64 measurements during a computational operation. Float64Gauge(name string, options ...Float64GaugeOption) (Float64Gauge, 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 }