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* Update README Move project status to top of project documentation and add explicit warnings that this project may introduce breaking changes. * Add disclaimer to public packages docs * Use explicit warning in README
124 lines
4.3 KiB
Go
124 lines
4.3 KiB
Go
// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/*
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Package otel provides an implementation of the OpenTelemetry API.
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This package is currently in a pre-GA phase. Backwards incompatible changes
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may be introduced in subsequent minor version releases as we work to track the
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evolving OpenTelemetry specification and user feedback.
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The provided API is used to instrument code and measure data about that code's
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performance and operation. The measured data, by default, is not processed or
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transmitted anywhere. An implementation of the OpenTelemetry SDK, like the
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default SDK implementation (go.opentelemetry.io/otel/sdk), and associated
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exporters are used to process and transport this data.
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Tracing
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To participate in distributed traces a Span needs to be created for the
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operation being performed as part of a traced workflow. It its simplest form:
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var tracer otel.Tracer
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func init() {
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tracer = global.Tracer("instrumentation/package/name")
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}
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func operation(ctx context.Context) {
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var span trace.Span
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ctx, span = tracer.Start(ctx, "operation")
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defer span.End()
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// ...
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}
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A Tracer is unique to the instrumentation and is used to create Spans.
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Instrumentation should be designed to accept a TracerProvider from which it
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can create its own unique Tracer. Alternatively, the registered global
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TracerProvider from the go.opentelemetry.io/otel/global package can be used as
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a default.
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const (
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name = "instrumentation/package/name"
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version = "0.1.0"
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)
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type Instrumentation struct {
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tracer otel.Tracer
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}
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func NewInstrumentation(tp otel.TracerProvider) *Instrumentation {
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if tp == nil {
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tp := global.TracerProvider()
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}
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return &Instrumentation{
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tracer: tp.Tracer(name, otel.WithTracerVersion(version)),
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}
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}
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func operation(ctx context.Context, inst *Instrumentation) {
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var span trace.Span
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ctx, span = inst.tracer.Start(ctx, "operation")
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defer span.End()
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// ...
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}
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Metric Measurements
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Measurements can be made about an operation being performed or the state of a
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system in general. These measurements can be crucial to the reliable operation
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of code and provide valuable insights about the inner workings of a system.
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Measurements are made using instruments provided by this package. The type of
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instrument used will depend on the type of measurement being made and of what
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part of a system is being measured.
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Instruments are categorized as Synchronous or Asynchronous and independently
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as Adding or Grouping. Synchronous instruments are called by the user with a
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Context. Asynchronous instruments are called by the SDK during collection.
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Additive instruments are semantically intended for capturing a sum. Grouping
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instruments are intended for capturing a distribution.
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Additive instruments may be monotonic, in which case they are non-decreasing
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and naturally define a rate.
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The synchronous instrument names are:
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Counter: additive, monotonic
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UpDownCounter: additive
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ValueRecorder: grouping
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and the asynchronous instruments are:
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SumObserver: additive, monotonic
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UpDownSumObserver: additive
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ValueObserver: grouping
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All instruments are provided with support for either float64 or int64 input
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values.
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An instrument is created using a Meter. Additionally, a Meter is used to
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record batches of synchronous measurements or asynchronous observations. A
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Meter is obtained using a MeterProvider. A Meter, like a Tracer, is unique to
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the instrumentation it instruments and must be named and versioned when
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created with a MeterProvider with the name and version of the instrumentation
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library.
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Instrumentation should be designed to accept a MeterProvider from which it can
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create its own unique Meter. Alternatively, the registered global
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MeterProvider from the go.opentelemetry.io/otel/api/global package can be used
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as a default.
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*/
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package otel // import "go.opentelemetry.io/otel"
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