// findConfigurationConflicts iterates over the provided flags searching for
// duplicated configurations and unknown keys. It returns an error with all the conflicts if
// it finds any.
func findConfigurationConflicts(config map[string]interface{}, flags *pflag.FlagSet) error {
// 1. Search keys from the file that we don't recognize as flags.
unknownKeys := make(map[string]interface{})
for key, value := range config {
if flag := flags.Lookup(key); flag == nil {
unknownKeys[key] = value
}
}
// 2. Discard values that implement NamedOption.
// Their configuration name differs from their flag name, like `labels` and `label`.
if len(unknownKeys) > 0 {
unknownNamedConflicts := func(f *pflag.Flag) {
if namedOption, ok := f.Value.(opts.NamedOption); ok {
if _, valid := unknownKeys[namedOption.Name()]; valid {
delete(unknownKeys, namedOption.Name())
}
}
}
flags.VisitAll(unknownNamedConflicts)
}
if len(unknownKeys) > 0 {
var unknown []string
for key := range unknownKeys {
unknown = append(unknown, key)
}
return fmt.Errorf("the following directives don't match any configuration option: %s", strings.Join(unknown, ", "))
}
var conflicts []string
printConflict := func(name string, flagValue, fileValue interface{}) string {
return fmt.Sprintf("%s: (from flag: %v, from file: %v)", name, flagValue, fileValue)
}
// 3. Search keys that are present as a flag and as a file option.
duplicatedConflicts := func(f *pflag.Flag) {
// search option name in the json configuration payload if the value is a named option
if namedOption, ok := f.Value.(opts.NamedOption); ok {
if optsValue, ok := config[namedOption.Name()]; ok {
conflicts = append(conflicts, printConflict(namedOption.Name(), f.Value.String(), optsValue))
}
} else {
// search flag name in the json configuration payload
for _, name := range []string{f.Name, f.Shorthand} {
if value, ok := config[name]; ok {
conflicts = append(conflicts, printConflict(name, f.Value.String(), value))
break
}
}
}
}
flags.Visit(duplicatedConflicts)
if len(conflicts) > 0 {
return fmt.Errorf("the following directives are specified both as a flag and in the configuration file: %s", strings.Join(conflicts, ", "))
}
return nil
}
// getFlagsFromEnv 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 => PREFIX_SOME_FLAG
func getFlagsFromEnv(prefix string, fs *pflag.FlagSet) {
alreadySet := make(map[string]bool)
fs.Visit(func(f *pflag.Flag) {
alreadySet[f.Name] = true
})
fs.VisitAll(func(f *pflag.Flag) {
if !alreadySet[f.Name] {
key := strings.ToUpper(prefix + "_" + strings.Replace(f.Name, "-", "_", -1))
val := os.Getenv(key)
if val != "" {
fs.Set(f.Name, val)
}
}
})
}
// 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, and any dashes are replaced by underscores. Environment
// variables additionally are prefixed by the given string followed by
// and underscore. For example, if prefix=PREFIX: some-flag => PREFIX_SOME_FLAG
func SetFlagsFromEnv(fs *flag.FlagSet, prefix string) (err error) {
alreadySet := make(map[string]bool)
fs.Visit(func(f *flag.Flag) {
alreadySet[f.Name] = true
})
fs.VisitAll(func(f *flag.Flag) {
if !alreadySet[f.Name] {
key := prefix + "_" + strings.ToUpper(strings.Replace(f.Name, "-", "_", -1))
val := os.Getenv(key)
if val != "" {
if serr := fs.Set(f.Name, val); serr != nil {
err = fmt.Errorf("invalid value %q for %s: %v", val, key, serr)
}
}
}
})
return err
}