twitch-bot/store.go

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2020-12-21 00:32:39 +00:00
package main
import (
"compress/gzip"
"encoding/json"
"os"
"sync"
"github.com/pkg/errors"
)
type storageFile struct {
Counters map[string]int64 `json:"counters"`
lock *sync.RWMutex
}
func newStorageFile() *storageFile {
return &storageFile{
Counters: map[string]int64{},
lock: new(sync.RWMutex),
}
}
func (s *storageFile) GetCounterValue(counter string) int64 {
s.lock.RLock()
defer s.lock.RUnlock()
return s.Counters[counter]
}
func (s *storageFile) Load() error {
s.lock.Lock()
defer s.lock.Unlock()
f, err := os.Open(cfg.StorageFile)
if err != nil {
if os.IsNotExist(err) {
// Store init state
return nil
}
return errors.Wrap(err, "open storage file")
}
defer f.Close()
zf, err := gzip.NewReader(f)
if err != nil {
return errors.Wrap(err, "create gzip reader")
}
defer zf.Close()
return errors.Wrap(
json.NewDecoder(zf).Decode(s),
"decode storage object",
)
}
func (s *storageFile) Save() error {
// NOTE(kahlers): DO NOT LOCK THIS, all calling functions are
// modifying functions and must have locks in place
f, err := os.Create(cfg.StorageFile)
if err != nil {
return errors.Wrap(err, "create storage file")
}
defer f.Close()
zf := gzip.NewWriter(f)
defer zf.Close()
return errors.Wrap(
json.NewEncoder(zf).Encode(s),
"encode storage object",
)
}
func (s *storageFile) UpdateCounter(counter string, value int64, absolute bool) error {
s.lock.Lock()
defer s.lock.Unlock()
if !absolute {
value = s.Counters[counter] + value
}
s.Counters[counter] = value
return errors.Wrap(s.Save(), "saving store")
}