forked from knadh/koanf
/
basicflag.go
69 lines (61 loc) · 2.03 KB
/
basicflag.go
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// Package basicflag implements a koanf.Provider that reads commandline
// parameters as conf maps using the Go's flag package.
package basicflag
import (
"errors"
"flag"
"github.com/Clever/koanf/maps"
)
// Pflag implements a pflag command line provider.
type Pflag struct {
delim string
flagset *flag.FlagSet
cb func(key string, value string) (string, interface{})
}
// Provider returns a commandline flags provider that returns
// a nested map[string]interface{} of environment variable where the
// nesting hierarchy of keys are defined by delim. For instance, the
// delim "." will convert the key `parent.child.key: 1`
// to `{parent: {child: {key: 1}}}`.
func Provider(f *flag.FlagSet, delim string) *Pflag {
return &Pflag{
flagset: f,
delim: delim,
}
}
// ProviderWithValue works exactly the same as Provider except the callback
// takes a (key, value) with the variable name and value and allows you
// to modify both. This is useful for cases where you may want to return
// other types like a string slice instead of just a string.
func ProviderWithValue(f *flag.FlagSet, delim string, cb func(key string, value string) (string, interface{})) *Pflag {
return &Pflag{
flagset: f,
delim: delim,
cb: cb,
}
}
// Read reads the flag variables and returns a nested conf map.
func (p *Pflag) Read() (map[string]interface{}, error) {
mp := make(map[string]interface{})
p.flagset.VisitAll(func(f *flag.Flag) {
if p.cb != nil {
key, value := p.cb(f.Name, f.Value.String())
// If the callback blanked the key, it should be omitted
if key == "" {
return
}
mp[key] = value
} else {
mp[f.Name] = f.Value.String()
}
})
return maps.Unflatten(mp, p.delim), nil
}
// ReadBytes is not supported by the basicflag koanf.
func (p *Pflag) ReadBytes() ([]byte, error) {
return nil, errors.New("basicflag provider does not support this method")
}
// Watch is not supported.
func (p *Pflag) Watch(cb func(event interface{}, err error)) error {
return errors.New("basicflag provider does not support this method")
}