// zpop pops a value from the ZSET key using WATCH/MULTI/EXEC commands.
func zpop(c redis.Conn, key string) (result string, err error) {
defer func() {
// Return connection to normal state on error.
if err != nil {
c.Do("DISCARD")
}
}()
// Loop until transaction is successful.
for {
if _, err := c.Do("WATCH", key); err != nil {
return "", err
}
members, err := redis.Strings(c.Do("ZRANGE", key, 0, 0))
if err != nil {
return "", err
}
if len(members) != 1 {
return "", redis.ErrNil
}
c.Send("MULTI")
c.Send("ZREM", key, members[0])
queued, err := c.Do("EXEC")
if err != nil {
return "", err
}
if queued != nil {
result = members[0]
break
}
}
return result, nil
}
func (m *baseModel) delete(id string, conn redis.Conn) error {
m.log.Debugf("Deleting %s %s", m.idType, id)
existing := reflect.New(m.objType).Interface()
existingErr := m.fetch(id, existing, false, conn)
if existingErr != nil && existingErr != RecordNotFound {
return fmt.Errorf("Failed fetching existing %s before delete. error:%s", m.idType, existingErr)
}
if existingErr == RecordNotFound {
lastUpdated, _ := m.getLastUpdated(id, conn)
if lastUpdated == nil {
// Hasn't ever existed...
return existingErr
}
// At this point we may have a RecordNotFound, but we may as well delete again anyway, just in case
m.log.Infof("%s id:%s appears to be already deleted, but we'll try again anyway.", m.idType, id)
}
defer syncFS()
conn.Send("MULTI")
conn.Send("SREM", m.idType+"s", id)
conn.Send("DEL", m.idType+":"+id)
_, err := conn.Do("EXEC")
if m.afterDelete != nil && existingErr == nil {
err = m.afterDelete(existing, conn)
if err != nil {
return fmt.Errorf("Failed on afterDelete: %s", err)
}
}
if m.sendEvent != nil {
m.sendEvent("deleted", id)
}
return m.markUpdated(id, time.Now(), conn)
}