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redis_kv_store.go
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/
redis_kv_store.go
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// Copyright © 2017 The Things Network
// Use of this source code is governed by the MIT license that can be found in the LICENSE file.
package storage
import (
"sort"
"strings"
"github.com/TheThingsNetwork/ttn/utils/errors"
"gopkg.in/redis.v5"
)
// RedisKVStore stores arbitrary data in Redis
type RedisKVStore struct {
*RedisStore
}
// NewRedisKVStore creates a new RedisKVStore
func NewRedisKVStore(client *redis.Client, prefix string) *RedisKVStore {
if !strings.HasSuffix(prefix, ":") {
prefix += ":"
}
return &RedisKVStore{
RedisStore: NewRedisStore(client, prefix),
}
}
// GetAll returns all results for the given keys, prepending the prefix to the keys if necessary
func (s *RedisKVStore) GetAll(keys []string, options *ListOptions) (map[string]string, error) {
if len(keys) == 0 {
return map[string]string{}, nil
}
for i, key := range keys {
if !strings.HasPrefix(key, s.prefix) {
keys[i] = s.prefix + key
}
}
sort.Strings(keys)
selectedKeys := selectKeys(keys, options)
if len(selectedKeys) == 0 {
return map[string]string{}, nil
}
pipe := s.client.Pipeline()
defer pipe.Close()
// Add all commands to pipeline
cmds := make(map[string]*redis.StringCmd)
for _, key := range selectedKeys {
cmds[key] = pipe.Get(key)
}
// Execute pipeline
_, err := pipe.Exec()
if err != nil {
return nil, err
}
// Get all results from pipeline
data := make(map[string]string)
for key, cmd := range cmds {
res, err := cmd.Result()
if err == nil {
data[strings.TrimPrefix(key, s.prefix)] = res
}
}
return data, nil
}
// List all results matching the selector, prepending the prefix to the selector if necessary
func (s *RedisKVStore) List(selector string, options *ListOptions) (map[string]string, error) {
allKeys, err := s.Keys(selector, options)
if err != nil {
return nil, err
}
return s.GetAll(allKeys, options)
}
// Get one result, prepending the prefix to the key if necessary
func (s *RedisKVStore) Get(key string) (string, error) {
if !strings.HasPrefix(key, s.prefix) {
key = s.prefix + key
}
result, err := s.client.Get(key).Result()
if err == redis.Nil || result == "" {
return "", errors.NewErrNotFound(key)
}
if err != nil {
return "", err
}
return result, nil
}
// Set a record, prepending the prefix to the key if necessary
func (s *RedisKVStore) Set(key string, value string) error {
if !strings.HasPrefix(key, s.prefix) {
key = s.prefix + key
}
return s.client.Set(key, value, 0).Err()
}
// Create a new record, prepending the prefix to the key if necessary
// This function returns an error if the record already exists
func (s *RedisKVStore) Create(key string, value string) error {
if !strings.HasPrefix(key, s.prefix) {
key = s.prefix + key
}
err := s.client.Watch(func(tx *redis.Tx) error {
exists, err := tx.Exists(key).Result()
if err != nil {
return err
}
if exists {
return errors.NewErrAlreadyExists(key)
}
_, err = tx.Pipelined(func(pipe *redis.Pipeline) error {
pipe.Set(key, value, 0)
return nil
})
if err != nil {
return err
}
return nil
}, key)
if err != nil {
return err
}
return nil
}
// Update an existing record, prepending the prefix to the key if necessary
// This function returns an error if the record does not exist
func (s *RedisKVStore) Update(key string, value string) error {
if !strings.HasPrefix(key, s.prefix) {
key = s.prefix + key
}
err := s.client.Watch(func(tx *redis.Tx) error {
exists, err := tx.Exists(key).Result()
if err != nil {
return err
}
if !exists {
return errors.NewErrNotFound(key)
}
_, err = tx.Pipelined(func(pipe *redis.Pipeline) error {
pipe.Set(key, value, 0)
return nil
})
if err != nil {
return err
}
return nil
}, key)
if err != nil {
return err
}
return nil
}