mirror of
https://github.com/open-telemetry/opentelemetry-go.git
synced 2024-12-04 09:43:23 +02:00
e3bf787c21
* Add agg limiting func * Add unit test for limitAttr * Add limiting to aggregate types * Add internal x pkg for experimental feature-flagging * Connect cardinality limit to metric SDK * Replace limitAttr fn with limiter type The Attribute method is still inlinable. * Use x.CardinalityLimit directly * Simplify limiter test * Add limiter benchmark * Document the AggregationLimit field * Test sum limits * Test limit for last value * Test histogram limit * Refactor expo hist test to use existing fixtures The tests for the exponential histogram create their own testing fixtures. There is nothing these new fixtures do that cannot already be done with the existing testing fixtures used by all the other aggregate functions. Unify the exponential histogram testing to use the existing fixtures. * Test the ExponentialHistogram limit * Fix lint * Add docs * Rename aggregation field to aggLimit --------- Co-authored-by: Robert Pająk <pellared@hotmail.com>
97 lines
3.2 KiB
Go
97 lines
3.2 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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// Package x contains support for OTel metric SDK experimental features.
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//
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// This package should only be used for features defined in the specification.
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// It should not be used for experiments or new project ideas.
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package x // import "go.opentelemetry.io/otel/sdk/metric/internal/x"
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import (
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"os"
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"strconv"
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"strings"
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)
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var (
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// Exemplars is an experimental feature flag that defines if exemplars
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// should be recorded for metric data-points.
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//
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// To enable this feature set the OTEL_GO_X_EXEMPLAR environment variable
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// to the case-insensitive string value of "true" (i.e. "True" and "TRUE"
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// will also enable this).
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Exemplars = newFeature("EXEMPLAR", func(v string) (string, bool) {
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if strings.ToLower(v) == "true" {
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return v, true
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}
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return "", false
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})
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// CardinalityLimit is an experimental feature flag that defines if
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// cardinality limits should be applied to the recorded metric data-points.
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//
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// To enable this feature set the OTEL_GO_X_CARDINALITY_LIMIT environment
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// variable to the integer limit value you want to use.
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//
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// Setting OTEL_GO_X_CARDINALITY_LIMIT to a value less than or equal to 0
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// will disable the cardinality limits.
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CardinalityLimit = newFeature("CARDINALITY_LIMIT", func(v string) (int, bool) {
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n, err := strconv.Atoi(v)
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if err != nil {
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return 0, false
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}
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return n, true
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})
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)
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// Feature is an experimental feature control flag. It provides a uniform way
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// to interact with these feature flags and parse their values.
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type Feature[T any] struct {
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key string
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parse func(v string) (T, bool)
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}
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func newFeature[T any](suffix string, parse func(string) (T, bool)) Feature[T] {
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const envKeyRoot = "OTEL_GO_X_"
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return Feature[T]{
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key: envKeyRoot + suffix,
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parse: parse,
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}
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}
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// Key returns the environment variable key that needs to be set to enable the
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// feature.
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func (f Feature[T]) Key() string { return f.key }
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// Lookup returns the user configured value for the feature and true if the
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// user has enabled the feature. Otherwise, if the feature is not enabled, a
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// zero-value and false are returned.
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func (f Feature[T]) Lookup() (v T, ok bool) {
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// https://github.com/open-telemetry/opentelemetry-specification/blob/62effed618589a0bec416a87e559c0a9d96289bb/specification/configuration/sdk-environment-variables.md#parsing-empty-value
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//
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// > The SDK MUST interpret an empty value of an environment variable the
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// > same way as when the variable is unset.
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vRaw := os.Getenv(f.key)
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if vRaw == "" {
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return v, ok
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}
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return f.parse(vRaw)
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}
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// Enabled returns if the feature is enabled.
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func (f Feature[T]) Enabled() bool {
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_, ok := f.Lookup()
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return ok
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}
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