micro/config/source/flag/flag.go

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2019-05-31 01:11:13 +03:00
package flag
import (
"errors"
"flag"
"github.com/imdario/mergo"
"github.com/micro/go-micro/config/source"
"strings"
"time"
)
type flagsrc struct {
opts source.Options
}
func (fs *flagsrc) Read() (*source.ChangeSet, error) {
if !flag.Parsed() {
return nil, errors.New("flags not parsed")
}
var changes map[string]interface{}
visitFn := func(f *flag.Flag) {
n := strings.ToLower(f.Name)
keys := strings.FieldsFunc(n, split)
reverse(keys)
tmp := make(map[string]interface{})
for i, k := range keys {
if i == 0 {
tmp[k] = f.Value
continue
}
tmp = map[string]interface{}{k: tmp}
}
mergo.Map(&changes, tmp) // need to sort error handling
return
}
unset, ok := fs.opts.Context.Value(includeUnsetKey{}).(bool)
if ok && unset {
flag.VisitAll(visitFn)
} else {
flag.Visit(visitFn)
}
b, err := fs.opts.Encoder.Encode(changes)
if err != nil {
return nil, err
}
cs := &source.ChangeSet{
Format: fs.opts.Encoder.String(),
Data: b,
Timestamp: time.Now(),
Source: fs.String(),
}
cs.Checksum = cs.Sum()
return cs, nil
}
func split(r rune) bool {
return r == '-' || r == '_'
}
func reverse(ss []string) {
for i := len(ss)/2 - 1; i >= 0; i-- {
opp := len(ss) - 1 - i
ss[i], ss[opp] = ss[opp], ss[i]
}
}
func (fs *flagsrc) Watch() (source.Watcher, error) {
return source.NewNoopWatcher()
}
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func (fs *flagsrc) Write(cs *source.ChangeSet) error {
return nil
}
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func (fs *flagsrc) String() string {
return "flag"
}
// NewSource returns a config source for integrating parsed flags.
// Hyphens are delimiters for nesting, and all keys are lowercased.
//
// Example:
// dbhost := flag.String("database-host", "localhost", "the db host name")
//
// {
// "database": {
// "host": "localhost"
// }
// }
func NewSource(opts ...source.Option) source.Source {
return &flagsrc{opts: source.NewOptions(opts...)}
}