opentelemetry-collector/featuregate/registry.go

138 lines
3.7 KiB
Go

// Copyright The OpenTelemetry Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package featuregate // import "go.opentelemetry.io/collector/featuregate"
import (
"fmt"
"sort"
"sync"
"sync/atomic"
)
var globalRegistry = NewRegistry()
// GlobalRegistry returns the global Registry.
func GlobalRegistry() *Registry {
return globalRegistry
}
type Registry struct {
gates sync.Map
}
// NewRegistry returns a new empty Registry.
func NewRegistry() *Registry {
return &Registry{}
}
// RegisterOption allows to configure additional information about a Gate during registration.
type RegisterOption interface {
apply(g *Gate)
}
type registerOptionFunc func(g *Gate)
func (ro registerOptionFunc) apply(g *Gate) {
ro(g)
}
// WithRegisterDescription adds description for the Gate.
func WithRegisterDescription(description string) RegisterOption {
return registerOptionFunc(func(g *Gate) {
g.description = description
})
}
// WithRegisterReferenceURL adds a URL that has all the contextual information about the Gate.
func WithRegisterReferenceURL(url string) RegisterOption {
return registerOptionFunc(func(g *Gate) {
g.referenceURL = url
})
}
// WithRegisterRemovalVersion is used when the Gate is considered StageStable,
// to inform users that referencing the gate is no longer needed.
func WithRegisterRemovalVersion(version string) RegisterOption {
return registerOptionFunc(func(g *Gate) {
g.removalVersion = version
})
}
// MustRegister like Register but panics if an invalid ID or gate options are provided.
func (r *Registry) MustRegister(id string, stage Stage, opts ...RegisterOption) *Gate {
g, err := r.Register(id, stage, opts...)
if err != nil {
panic(err)
}
return g
}
// Register a Gate and return it. The returned Gate can be used to check if is enabled or not.
func (r *Registry) Register(id string, stage Stage, opts ...RegisterOption) (*Gate, error) {
g := &Gate{
id: id,
stage: stage,
}
for _, opt := range opts {
opt.apply(g)
}
switch g.stage {
case StageAlpha:
g.enabled = &atomic.Bool{}
case StageBeta, StageStable:
enabled := &atomic.Bool{}
enabled.Store(true)
g.enabled = enabled
default:
return nil, fmt.Errorf("unknown stage value %q for gate %q", stage, id)
}
if g.stage == StageStable && g.removalVersion == "" {
return nil, fmt.Errorf("no removal version set for stable gate %q", id)
}
if _, loaded := r.gates.LoadOrStore(id, g); loaded {
return nil, fmt.Errorf("attempted to add pre-existing gate %q", id)
}
return g, nil
}
// Set the enabled valued for a Gate identified by the given id.
func (r *Registry) Set(id string, enabled bool) error {
v, ok := r.gates.Load(id)
if !ok {
return fmt.Errorf("no such feature gate -%v", id)
}
g := v.(*Gate)
if g.stage == StageStable {
return fmt.Errorf("feature gate %s is stable, can not be modified", id)
}
g.enabled.Store(enabled)
return nil
}
// VisitAll visits all the gates in lexicographical order, calling fn for each.
func (r *Registry) VisitAll(fn func(*Gate)) {
var gates []*Gate
r.gates.Range(func(key, value any) bool {
gates = append(gates, value.(*Gate))
return true
})
sort.Slice(gates, func(i, j int) bool {
return gates[i].ID() < gates[j].ID()
})
for i := range gates {
fn(gates[i])
}
}