| // Copyright 2015 The etcd 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 flags implements command-line flag parsing. |
| package flags |
| |
| import ( |
| "flag" |
| "fmt" |
| "net/url" |
| "os" |
| "strings" |
| |
| "github.com/coreos/pkg/capnslog" |
| "github.com/spf13/pflag" |
| ) |
| |
| var ( |
| plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "pkg/flags") |
| ) |
| |
| // DeprecatedFlag encapsulates a flag that may have been previously valid but |
| // is now deprecated. If a DeprecatedFlag is set, an error occurs. |
| type DeprecatedFlag struct { |
| Name string |
| } |
| |
| func (f *DeprecatedFlag) Set(_ string) error { |
| return fmt.Errorf(`flag "-%s" is no longer supported.`, f.Name) |
| } |
| |
| func (f *DeprecatedFlag) String() string { |
| return "" |
| } |
| |
| // IgnoredFlag encapsulates a flag that may have been previously valid but is |
| // now ignored. If an IgnoredFlag is set, a warning is printed and |
| // operation continues. |
| type IgnoredFlag struct { |
| Name string |
| } |
| |
| // IsBoolFlag is defined to allow the flag to be defined without an argument |
| func (f *IgnoredFlag) IsBoolFlag() bool { |
| return true |
| } |
| |
| func (f *IgnoredFlag) Set(s string) error { |
| plog.Warningf(`flag "-%s" is no longer supported - ignoring.`, f.Name) |
| return nil |
| } |
| |
| func (f *IgnoredFlag) String() string { |
| return "" |
| } |
| |
| // SetFlagsFromEnv parses all registered flags in the given flagset, |
| // and if they are not already set it attempts to set their values from |
| // environment variables. Environment variables take the name of the flag but |
| // are UPPERCASE, have the given prefix and any dashes are replaced by |
| // underscores - for example: some-flag => ETCD_SOME_FLAG |
| func SetFlagsFromEnv(prefix string, fs *flag.FlagSet) error { |
| var err error |
| alreadySet := make(map[string]bool) |
| fs.Visit(func(f *flag.Flag) { |
| alreadySet[FlagToEnv(prefix, f.Name)] = true |
| }) |
| usedEnvKey := make(map[string]bool) |
| fs.VisitAll(func(f *flag.Flag) { |
| if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, true); serr != nil { |
| err = serr |
| } |
| }) |
| verifyEnv(prefix, usedEnvKey, alreadySet) |
| return err |
| } |
| |
| // SetPflagsFromEnv is similar to SetFlagsFromEnv. However, the accepted flagset type is pflag.FlagSet |
| // and it does not do any logging. |
| func SetPflagsFromEnv(prefix string, fs *pflag.FlagSet) error { |
| var err error |
| alreadySet := make(map[string]bool) |
| usedEnvKey := make(map[string]bool) |
| fs.VisitAll(func(f *pflag.Flag) { |
| if f.Changed { |
| alreadySet[FlagToEnv(prefix, f.Name)] = true |
| } |
| if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, false); serr != nil { |
| err = serr |
| } |
| }) |
| verifyEnv(prefix, usedEnvKey, alreadySet) |
| return err |
| } |
| |
| // FlagToEnv converts flag string to upper-case environment variable key string. |
| func FlagToEnv(prefix, name string) string { |
| return prefix + "_" + strings.ToUpper(strings.Replace(name, "-", "_", -1)) |
| } |
| |
| func verifyEnv(prefix string, usedEnvKey, alreadySet map[string]bool) { |
| for _, env := range os.Environ() { |
| kv := strings.SplitN(env, "=", 2) |
| if len(kv) != 2 { |
| plog.Warningf("found invalid env %s", env) |
| } |
| if usedEnvKey[kv[0]] { |
| continue |
| } |
| if alreadySet[kv[0]] { |
| // TODO: exit with error in v3.4 |
| plog.Warningf("recognized environment variable %s, but unused: shadowed by corresponding flag", kv[0]) |
| continue |
| } |
| if strings.HasPrefix(env, prefix+"_") { |
| plog.Warningf("unrecognized environment variable %s", env) |
| } |
| } |
| } |
| |
| type flagSetter interface { |
| Set(fk string, fv string) error |
| } |
| |
| func setFlagFromEnv(fs flagSetter, prefix, fname string, usedEnvKey, alreadySet map[string]bool, log bool) error { |
| key := FlagToEnv(prefix, fname) |
| if !alreadySet[key] { |
| val := os.Getenv(key) |
| if val != "" { |
| usedEnvKey[key] = true |
| if serr := fs.Set(fname, val); serr != nil { |
| return fmt.Errorf("invalid value %q for %s: %v", val, key, serr) |
| } |
| if log { |
| plog.Infof("recognized and used environment variable %s=%s", key, val) |
| } |
| } |
| } |
| return nil |
| } |
| |
| // URLsFromFlag returns a slices from url got from the flag. |
| func URLsFromFlag(fs *flag.FlagSet, urlsFlagName string) []url.URL { |
| return []url.URL(*fs.Lookup(urlsFlagName).Value.(*URLsValue)) |
| } |
| |
| func IsSet(fs *flag.FlagSet, name string) bool { |
| set := false |
| fs.Visit(func(f *flag.Flag) { |
| if f.Name == name { |
| set = true |
| } |
| }) |
| return set |
| } |