Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

1 files changed, 211 insertions, 0 deletions

diff --git a/vendor/k8s.io/apiserver/pkg/util/feature/feature_gate.go b/vendor/k8s.io/apiserver/pkg/util/feature/feature_gate.go
new file mode 100644
index 000000000..e7226688c
--- /dev/null
+++ b/vendor/k8s.io/apiserver/pkg/util/feature/feature_gate.go
@@ -0,0 +1,211 @@
+/*
+Copyright 2016 The Kubernetes 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 feature
+
+import (
+	"fmt"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/golang/glog"
+	"github.com/spf13/pflag"
+)
+
+type Feature string
+
+const (
+	flagName = "feature-gates"
+
+	// allAlphaGate is a global toggle for alpha features. Per-feature key
+	// values override the default set by allAlphaGate. Examples:
+	//   AllAlpha=false,NewFeature=true  will result in newFeature=true
+	//   AllAlpha=true,NewFeature=false  will result in newFeature=false
+	allAlphaGate Feature = "AllAlpha"
+)
+
+var (
+	// The generic features.
+	defaultFeatures = map[Feature]FeatureSpec{
+		allAlphaGate: {Default: false, PreRelease: Alpha},
+	}
+
+	// Special handling for a few gates.
+	specialFeatures = map[Feature]func(f *featureGate, val bool){
+		allAlphaGate: setUnsetAlphaGates,
+	}
+
+	// DefaultFeatureGate is a shared global FeatureGate.
+	DefaultFeatureGate FeatureGate = NewFeatureGate()
+)
+
+type FeatureSpec struct {
+	Default    bool
+	PreRelease prerelease
+}
+
+type prerelease string
+
+const (
+	// Values for PreRelease.
+	Alpha = prerelease("ALPHA")
+	Beta  = prerelease("BETA")
+	GA    = prerelease("")
+)
+
+// FeatureGate parses and stores flag gates for known features from
+// a string like feature1=true,feature2=false,...
+type FeatureGate interface {
+	AddFlag(fs *pflag.FlagSet)
+	Set(value string) error
+	Enabled(key Feature) bool
+	Add(features map[Feature]FeatureSpec) error
+	KnownFeatures() []string
+}
+
+// featureGate implements FeatureGate as well as pflag.Value for flag parsing.
+type featureGate struct {
+	known   map[Feature]FeatureSpec
+	special map[Feature]func(*featureGate, bool)
+	enabled map[Feature]bool
+
+	// is set to true when AddFlag is called. Note: initialization is not go-routine safe, lookup is
+	closed bool
+}
+
+func setUnsetAlphaGates(f *featureGate, val bool) {
+	for k, v := range f.known {
+		if v.PreRelease == Alpha {
+			if _, found := f.enabled[k]; !found {
+				f.enabled[k] = val
+			}
+		}
+	}
+}
+
+// Set, String, and Type implement pflag.Value
+var _ pflag.Value = &featureGate{}
+
+func NewFeatureGate() *featureGate {
+	f := &featureGate{
+		known:   map[Feature]FeatureSpec{},
+		special: specialFeatures,
+		enabled: map[Feature]bool{},
+	}
+	for k, v := range defaultFeatures {
+		f.known[k] = v
+	}
+	return f
+}
+
+// Set Parses a string of the form // "key1=value1,key2=value2,..." into a
+// map[string]bool of known keys or returns an error.
+func (f *featureGate) Set(value string) error {
+	for _, s := range strings.Split(value, ",") {
+		if len(s) == 0 {
+			continue
+		}
+		arr := strings.SplitN(s, "=", 2)
+		k := Feature(strings.TrimSpace(arr[0]))
+		_, ok := f.known[Feature(k)]
+		if !ok {
+			return fmt.Errorf("unrecognized key: %s", k)
+		}
+		if len(arr) != 2 {
+			return fmt.Errorf("missing bool value for %s", k)
+		}
+		v := strings.TrimSpace(arr[1])
+		boolValue, err := strconv.ParseBool(v)
+		if err != nil {
+			return fmt.Errorf("invalid value of %s: %s, err: %v", k, v, err)
+		}
+		f.enabled[k] = boolValue
+
+		// Handle "special" features like "all alpha gates"
+		if fn, found := f.special[k]; found {
+			fn(f, boolValue)
+		}
+	}
+
+	glog.Infof("feature gates: %v", f.enabled)
+	return nil
+}
+
+func (f *featureGate) String() string {
+	pairs := []string{}
+	for k, v := range f.enabled {
+		pairs = append(pairs, fmt.Sprintf("%s=%t", k, v))
+	}
+	sort.Strings(pairs)
+	return strings.Join(pairs, ",")
+}
+
+func (f *featureGate) Type() string {
+	return "mapStringBool"
+}
+
+func (f *featureGate) Add(features map[Feature]FeatureSpec) error {
+	if f.closed {
+		return fmt.Errorf("cannot add a feature gate after adding it to the flag set")
+	}
+
+	for name, spec := range features {
+		if existingSpec, found := f.known[name]; found {
+			if existingSpec == spec {
+				continue
+			}
+			return fmt.Errorf("feature gate %q with different spec already exists: %v", name, existingSpec)
+		}
+
+		f.known[name] = spec
+	}
+	return nil
+}
+
+func (f *featureGate) Enabled(key Feature) bool {
+	defaultValue := f.known[key].Default
+	if f.enabled != nil {
+		if v, ok := f.enabled[key]; ok {
+			return v
+		}
+	}
+	return defaultValue
+}
+
+// AddFlag adds a flag for setting global feature gates to the specified FlagSet.
+func (f *featureGate) AddFlag(fs *pflag.FlagSet) {
+	f.closed = true
+
+	known := f.KnownFeatures()
+	fs.Var(f, flagName, ""+
+		"A set of key=value pairs that describe feature gates for alpha/experimental features. "+
+		"Options are:\n"+strings.Join(known, "\n"))
+}
+
+// Returns a string describing the FeatureGate's known features.
+func (f *featureGate) KnownFeatures() []string {
+	var known []string
+	for k, v := range f.known {
+		pre := ""
+		if v.PreRelease != GA {
+			pre = fmt.Sprintf("%s - ", v.PreRelease)
+		}
+		known = append(known, fmt.Sprintf("%s=true|false (%sdefault=%t)", k, pre, v.Default))
+	}
+	sort.Strings(known)
+	return known
+}