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Diffstat (limited to 'vendor/go.opentelemetry.io/otel/metric/doc.go')
| -rw-r--r-- | vendor/go.opentelemetry.io/otel/metric/doc.go | 124 |
1 files changed, 5 insertions, 119 deletions
diff --git a/vendor/go.opentelemetry.io/otel/metric/doc.go b/vendor/go.opentelemetry.io/otel/metric/doc.go index bda14e10a..bd6f43437 100644 --- a/vendor/go.opentelemetry.io/otel/metric/doc.go +++ b/vendor/go.opentelemetry.io/otel/metric/doc.go @@ -13,125 +13,11 @@ // limitations under the License. /* -Package metric provides the OpenTelemetry API used to measure metrics about -source code operation. +Package metric provides an implementation of the metrics part of the +OpenTelemetry API. -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], [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], -[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], [Float64ObservableCounter]) are -designed to measure values that never decrease in value, but instead only -incrementally increase in value. UpDownCounters ([Int64UpDownCounter], -[Float64UpDownCounter], [Int64ObservableUpDownCounter], -[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], [Float64Histogram]) should be -used. Finally, when just the most recent measurement needs to be conveyed about an -asynchronous measurement, a Gauge ([Int64ObservableGauge], -[Float64ObservableGauge]) should be used. - -See the [OpenTelemetry documentation] for more information about instruments -and their intended use. - -# 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 want 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 +This package is currently in a pre-GA phase. Backwards incompatible changes +may be introduced in subsequent minor version releases as we work to track the +evolving OpenTelemetry specification and user feedback. */ package metric // import "go.opentelemetry.io/otel/metric" |