87 lines
1.7 KiB
Go
87 lines
1.7 KiB
Go
package jsondb
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import (
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"encoding/json"
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"errors"
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"fmt"
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"math/rand"
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"time"
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)
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var errCacheDisabled = errors.New("cache disabled")
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// SetCache sets a cache key.
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func (db *DB) SetCache(key, value string, expires int) error {
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if db.Cache == nil {
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return errCacheDisabled
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}
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return db.Cache.Set(key, []byte(value), expires)
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}
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// SetJSONCache caches a JSON object.
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func (db *DB) SetJSONCache(key string, v interface{}, expires int) error {
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if db.Cache == nil {
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return errCacheDisabled
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}
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bytes, err := json.Marshal(v)
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if err != nil {
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return err
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}
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return db.SetCache(key, string(bytes), expires)
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}
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// GetCache gets a cache key.
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func (db *DB) GetCache(key string) (string, error) {
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if db.Cache == nil {
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return "", errCacheDisabled
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}
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v, err := db.Cache.Get(key)
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return string(v), err
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}
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// DeleteCache deletes a cache key.
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func (db *DB) DeleteCache(key string) error {
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if db.Cache == nil {
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return errCacheDisabled
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}
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db.Cache.Delete(key)
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return nil
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}
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// LockCache implements 'file locking' in your cache.
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func (db *DB) LockCache(key string) bool {
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if db.Cache == nil {
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return true
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}
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log.Info("LockCache(%s)", key)
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var (
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// In seconds
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timeout = 5 * time.Second
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expire = 20
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)
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identifier := fmt.Sprintf("%d", rand.Uint64())
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log.Info("id: %s", identifier)
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end := time.Now().Add(timeout)
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for time.Now().Before(end) {
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if ok := db.Cache.Lock("lock:"+key, identifier, expire); ok {
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log.Info("JsonDB: Acquired lock for %s", key)
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return true
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}
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time.Sleep(1 * time.Millisecond)
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}
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log.Error("JsonDB: lock timeout for %s", key)
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return false
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}
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// UnlockCache releases the lock on a cache key.
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func (db *DB) UnlockCache(key string) {
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if db.Cache == nil {
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return
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}
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db.Cache.Unlock("lock:" + key)
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}
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