mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
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208 lines
6.3 KiB
Go
208 lines
6.3 KiB
Go
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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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package featuregate // import "go.opentelemetry.io/collector/featuregate"
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import (
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"fmt"
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"net/url"
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"regexp"
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"sort"
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"sync"
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"sync/atomic"
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"github.com/hashicorp/go-version"
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)
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var (
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globalRegistry = NewRegistry()
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// idRegexp is used to validate the ID of a Gate.
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// IDs' characters must be alphanumeric or dots.
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idRegexp = regexp.MustCompile(`^[0-9a-zA-Z\.]*$`)
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)
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// GlobalRegistry returns the global Registry.
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func GlobalRegistry() *Registry {
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return globalRegistry
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}
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type Registry struct {
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gates sync.Map
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}
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// NewRegistry returns a new empty Registry.
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func NewRegistry() *Registry {
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return &Registry{}
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}
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// RegisterOption allows to configure additional information about a Gate during registration.
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type RegisterOption interface {
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apply(g *Gate) error
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}
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type registerOptionFunc func(g *Gate) error
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func (ro registerOptionFunc) apply(g *Gate) error {
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return ro(g)
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}
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// WithRegisterDescription adds description for the Gate.
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func WithRegisterDescription(description string) RegisterOption {
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return registerOptionFunc(func(g *Gate) error {
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g.description = description
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return nil
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})
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}
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// WithRegisterReferenceURL adds a URL that has all the contextual information about the Gate.
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// referenceURL must be a valid URL as defined by `net/url.Parse`.
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func WithRegisterReferenceURL(referenceURL string) RegisterOption {
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return registerOptionFunc(func(g *Gate) error {
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if _, err := url.Parse(referenceURL); err != nil {
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return fmt.Errorf("WithRegisterReferenceURL: invalid reference URL %q: %w", referenceURL, err)
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}
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g.referenceURL = referenceURL
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return nil
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})
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}
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// WithRegisterFromVersion is used to set the Gate "FromVersion".
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// The "FromVersion" contains the Collector release when a feature is introduced.
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// fromVersion must be a valid version string: it may start with 'v' and must be in the format Major.Minor.Patch[-PreRelease].
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// PreRelease is optional and may have dashes, tildes and ASCII alphanumeric characters.
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func WithRegisterFromVersion(fromVersion string) RegisterOption {
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return registerOptionFunc(func(g *Gate) error {
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from, err := version.NewVersion(fromVersion)
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if err != nil {
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return fmt.Errorf("WithRegisterFromVersion: invalid version %q: %w", fromVersion, err)
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}
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g.fromVersion = from
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return nil
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})
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}
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// WithRegisterToVersion is used to set the Gate "ToVersion".
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// The "ToVersion", if not empty, contains the last Collector release in which you can still use a feature gate.
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// If the feature stage is either "Deprecated" or "Stable", the "ToVersion" is the Collector release when the feature is removed.
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// toVersion must be a valid version string: it may start with 'v' and must be in the format Major.Minor.Patch[-PreRelease].
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// PreRelease is optional and may have dashes, tildes and ASCII alphanumeric characters.
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func WithRegisterToVersion(toVersion string) RegisterOption {
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return registerOptionFunc(func(g *Gate) error {
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to, err := version.NewVersion(toVersion)
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if err != nil {
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return fmt.Errorf("WithRegisterToVersion: invalid version %q: %w", toVersion, err)
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}
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g.toVersion = to
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return nil
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})
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}
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// MustRegister like Register but panics if an invalid ID or gate options are provided.
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func (r *Registry) MustRegister(id string, stage Stage, opts ...RegisterOption) *Gate {
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g, err := r.Register(id, stage, opts...)
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if err != nil {
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panic(err)
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}
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return g
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}
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func validateID(id string) error {
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if id == "" {
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return fmt.Errorf("empty ID")
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}
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if !idRegexp.MatchString(id) {
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return fmt.Errorf("invalid character(s) in ID")
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}
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return nil
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}
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// Register a Gate and return it. The returned Gate can be used to check if is enabled or not.
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// id must be an ASCII alphanumeric nonempty string. Dots are allowed for namespacing.
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func (r *Registry) Register(id string, stage Stage, opts ...RegisterOption) (*Gate, error) {
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if err := validateID(id); err != nil {
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return nil, fmt.Errorf("invalid ID %q: %w", id, err)
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}
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g := &Gate{
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id: id,
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stage: stage,
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}
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for _, opt := range opts {
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err := opt.apply(g)
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if err != nil {
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return nil, fmt.Errorf("failed to apply option: %w", err)
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}
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}
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switch g.stage {
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case StageAlpha, StageDeprecated:
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g.enabled = &atomic.Bool{}
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case StageBeta, StageStable:
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enabled := &atomic.Bool{}
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enabled.Store(true)
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g.enabled = enabled
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default:
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return nil, fmt.Errorf("unknown stage value %q for gate %q", stage, id)
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}
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if (g.stage == StageStable || g.stage == StageDeprecated) && g.toVersion == nil {
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return nil, fmt.Errorf("no removal version set for %v gate %q", g.stage.String(), id)
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}
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if g.fromVersion != nil && g.toVersion != nil && g.toVersion.LessThan(g.fromVersion) {
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return nil, fmt.Errorf("toVersion %q is before fromVersion %q", g.toVersion, g.fromVersion)
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}
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if _, loaded := r.gates.LoadOrStore(id, g); loaded {
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return nil, fmt.Errorf("attempted to add pre-existing gate %q", id)
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}
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return g, nil
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}
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// Set the enabled valued for a Gate identified by the given id.
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func (r *Registry) Set(id string, enabled bool) error {
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v, ok := r.gates.Load(id)
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if !ok {
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validGates := []string{}
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r.VisitAll(func(g *Gate) {
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validGates = append(validGates, g.ID())
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})
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return fmt.Errorf("no such feature gate %q. valid gates: %v", id, validGates)
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}
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g := v.(*Gate)
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switch g.stage {
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case StageStable:
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if !enabled {
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return fmt.Errorf("feature gate %q is stable, can not be disabled", id)
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}
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fmt.Printf("Feature gate %q is stable and already enabled. It will be removed in version %v and continued use of the gate after version %v will result in an error.\n", id, g.toVersion, g.toVersion)
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case StageDeprecated:
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if enabled {
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return fmt.Errorf("feature gate %q is deprecated, can not be enabled", id)
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}
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fmt.Printf("Feature gate %q is deprecated and already disabled. It will be removed in version %v and continued use of the gate after version %v will result in an error.\n", id, g.toVersion, g.toVersion)
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default:
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g.enabled.Store(enabled)
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}
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return nil
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}
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// VisitAll visits all the gates in lexicographical order, calling fn for each.
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func (r *Registry) VisitAll(fn func(*Gate)) {
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var gates []*Gate
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r.gates.Range(func(key, value any) bool {
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gates = append(gates, value.(*Gate))
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return true
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})
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sort.Slice(gates, func(i, j int) bool {
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return gates[i].ID() < gates[j].ID()
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})
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for i := range gates {
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fn(gates[i])
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}
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}
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