mirror of https://github.com/k3s-io/k3s
122 lines
3.6 KiB
Go
122 lines
3.6 KiB
Go
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// Copyright 2015 The etcd 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 flags implements command-line flag parsing.
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package flags
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import (
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"flag"
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"fmt"
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"os"
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"strings"
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"github.com/coreos/pkg/capnslog"
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"github.com/spf13/pflag"
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)
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var plog = capnslog.NewPackageLogger("go.etcd.io/etcd", "pkg/flags")
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// SetFlagsFromEnv parses all registered flags in the given flagset,
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// and if they are not already set it attempts to set their values from
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// environment variables. Environment variables take the name of the flag but
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// are UPPERCASE, have the given prefix and any dashes are replaced by
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// underscores - for example: some-flag => ETCD_SOME_FLAG
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func SetFlagsFromEnv(prefix string, fs *flag.FlagSet) error {
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var err error
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alreadySet := make(map[string]bool)
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fs.Visit(func(f *flag.Flag) {
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alreadySet[FlagToEnv(prefix, f.Name)] = true
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})
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usedEnvKey := make(map[string]bool)
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fs.VisitAll(func(f *flag.Flag) {
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if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, true); serr != nil {
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err = serr
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}
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})
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verifyEnv(prefix, usedEnvKey, alreadySet)
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return err
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}
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// SetPflagsFromEnv is similar to SetFlagsFromEnv. However, the accepted flagset type is pflag.FlagSet
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// and it does not do any logging.
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func SetPflagsFromEnv(prefix string, fs *pflag.FlagSet) error {
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var err error
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alreadySet := make(map[string]bool)
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usedEnvKey := make(map[string]bool)
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fs.VisitAll(func(f *pflag.Flag) {
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if f.Changed {
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alreadySet[FlagToEnv(prefix, f.Name)] = true
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}
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if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, false); serr != nil {
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err = serr
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}
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})
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verifyEnv(prefix, usedEnvKey, alreadySet)
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return err
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}
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// FlagToEnv converts flag string to upper-case environment variable key string.
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func FlagToEnv(prefix, name string) string {
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return prefix + "_" + strings.ToUpper(strings.Replace(name, "-", "_", -1))
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}
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func verifyEnv(prefix string, usedEnvKey, alreadySet map[string]bool) {
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for _, env := range os.Environ() {
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kv := strings.SplitN(env, "=", 2)
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if len(kv) != 2 {
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plog.Warningf("found invalid env %s", env)
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}
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if usedEnvKey[kv[0]] {
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continue
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}
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if alreadySet[kv[0]] {
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plog.Fatalf("conflicting environment variable %q is shadowed by corresponding command-line flag (either unset environment variable or disable flag)", kv[0])
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}
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if strings.HasPrefix(env, prefix+"_") {
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plog.Warningf("unrecognized environment variable %s", env)
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}
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}
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}
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type flagSetter interface {
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Set(fk string, fv string) error
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}
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func setFlagFromEnv(fs flagSetter, prefix, fname string, usedEnvKey, alreadySet map[string]bool, log bool) error {
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key := FlagToEnv(prefix, fname)
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if !alreadySet[key] {
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val := os.Getenv(key)
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if val != "" {
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usedEnvKey[key] = true
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if serr := fs.Set(fname, val); serr != nil {
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return fmt.Errorf("invalid value %q for %s: %v", val, key, serr)
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}
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if log {
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plog.Infof("recognized and used environment variable %s=%s", key, val)
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}
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}
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}
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return nil
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}
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func IsSet(fs *flag.FlagSet, name string) bool {
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set := false
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fs.Visit(func(f *flag.Flag) {
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if f.Name == name {
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set = true
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}
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})
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return set
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}
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