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60 lines
2.9 KiB
Go
60 lines
2.9 KiB
Go
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// 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 instrument provides the OpenTelemetry API instruments used to make
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measurements.
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Each instrument is designed to make measurements of a particular type. Broadly,
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all instruments fall into two overlapping logical categories: asynchronous or
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synchronous, and int64 or float64.
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All synchronous instruments ([Int64Counter], [Int64UpDownCounter],
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[Int64Histogram], [Float64Counter], [Float64UpDownCounter], [Float64Histogram])
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are used to measure the operation and performance of source code during the
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source code execution. These instruments only make measurements when the source
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code they instrument is run.
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All asynchronous instruments ([Int64ObservableCounter],
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[Int64ObservableUpDownCounter], [Int64ObservableGauge],
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[Float64ObservableCounter], [Float64ObservableUpDownCounter],
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[Float64ObservableGauge]) are used to measure metrics outside of the execution
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of source code. They are said to make "observations" via a callback function
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called once every measurement collection cycle.
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Each instrument is also grouped by the value type it measures. Either int64 or
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float64. The value being measured will dictate which instrument in these
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categories to use.
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Outside of these two broad categories, instruments are described by the
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function they are designed to serve. All Counters ([Int64Counter],
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[Float64Counter], [Int64ObservableCounter], [Float64ObservableCounter]) are
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designed to measure values that never decrease in value, but instead only
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incrementally increase in value. UpDownCounters ([Int64UpDownCounter],
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[Float64UpDownCounter], [Int64ObservableUpDownCounter],
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[Float64ObservableUpDownCounter]) on the other hand, are designed to measure
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values that can increase and decrease. When more information
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needs to be conveyed about all the synchronous measurements made during a
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collection cycle, a Histogram ([Int64Histogram], [Float64Histogram]) should be
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used. Finally, when just the most recent measurement needs to be conveyed about an
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asynchronous measurement, a Gauge ([Int64ObservableGauge],
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[Float64ObservableGauge]) should be used.
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See the [OpenTelemetry documentation] for more information about instruments
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and their intended use.
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[OpenTelemetry documentation]: https://opentelemetry.io/docs/concepts/signals/metrics/
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*/
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package instrument // import "go.opentelemetry.io/otel/metric/instrument"
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