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main.go
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main.go
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package main
import (
"os"
"fmt"
"flag"
"encoding/json"
"github.com/sug0/go-seq"
"github.com/sug0/go-exit"
"github.com/gofrs/flock"
)
var (
keypath string
)
func main() {
defer exit.Handler()
var del, key, path string
flag.StringVar(&path, "p", "", "The directory to save the IDs in.")
flag.StringVar(&key, "k", "", "The key of the ID to generate.")
flag.StringVar(&del, "f", "", "Delete the specified ID from a given key.")
flag.Parse()
if path == "" {
exit.WithMsg(os.Stderr, 1, "%s: No given ID directory.", os.Args[0])
}
if key == "" {
exit.WithMsg(os.Stderr, 1, "%s: No key given.", os.Args[0])
}
lockpath := fmt.Sprintf("%s%c%s.lock", path, os.PathSeparator, key)
keypath = fmt.Sprintf("%s%c%s.json", path, os.PathSeparator, key)
locker := flock.NewFlock(lockpath)
locker.Lock()
seq, err := openIds()
if err != nil {
locker.Unlock()
exit.WithMsg(os.Stderr, 1, "%s: %s", os.Args[0], err)
}
defer locker.Unlock()
defer saveIds(seq)
if del != "" {
if err = seq.Free([]byte(del)); err != nil {
exit.WithMsg(os.Stderr, 1, "%s: Can't free the ID given: %s", os.Args[0], del)
}
} else {
os.Stdout.Write(seq.Next())
os.Stdout.Write([]byte{'\n'})
}
}
func openIds() (*sequence.Seq, error) {
f, err := os.Open(keypath)
if err != nil {
return sequence.NewSeq(), nil
}
defer f.Close()
var seq sequence.Seq
dec := json.NewDecoder(f)
if err = dec.Decode(&seq); err != nil {
return nil, err
}
return &seq, nil
}
func saveIds(seq *sequence.Seq) error {
f, err := os.Create(keypath)
if err != nil {
return err
}
defer f.Close()
enc := json.NewEncoder(f)
if err = enc.Encode(seq); err != nil {
return err
}
return nil
}