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Akshay Bharambe authoredcbbf773f
cache_redis.go 7.73 KiB
package cachemdl/*Provides cache access and manipulation methods for redis serverImplements cacher interface.Official docs -1. redis client - https://github.com/go-redis/redis2. redis server - https://redis.io/Note - corelab.mkcl.org/MKCLOS/coredevelopmentplatform/corepkgv2/loggermdl must be initialized before use*/import ( "encoding/json" "errors" "log" "strings" "time" "corelab.mkcl.org/MKCLOS/coredevelopmentplatform/corepkgv2/loggermdl" "github.com/go-redis/redis")const ( noExp time.Duration = 0 // NotOK refers to a unsuccessfull operations NotOK int64 = 0 // OK refers to a successfull operations OK int64 = 1 keySplitter = ":")// RedisCache represents a Redis client with provided configuration. Do not change configuration at runtime.type RedisCache struct { cli *redis.Client // represents redis client opt *redis.Options // keyStr string // "<Prefix>:" addPrefix bool // connected bool // will be enabled if redis client connects to server Addr string // redis server address, default "127.0.0.1:6379" DB int // redis DB on provided server, default 0 Password string // Expiration time.Duration // this duration will be used for Set() method Prefix string // this will be used for storing keys for provided project}type configRedis struct { addr string // redis server address, default "127.0.0.1:6379" db int // redis DB on provided server, default 0 password string // expiration time.Duration // this duration will be used for Set() method prefix string // this will be used for storing keys for provided project}type redisOption func(*configRedis)func RedisWithAddr(addr string) redisOption { return func(cfg *configRedis) { cfg.addr = addr }}func RedisWithDB(db int) redisOption {7172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
return func(cfg *configRedis) {
cfg.db = db
}
}
func RedisWithPrefix(pfx string) redisOption {
return func(cfg *configRedis) {
cfg.prefix = pfx
}
}
func RedisWithPassword(p string) redisOption {
return func(cfg *configRedis) {
cfg.password = p
}
}
func RedisWithExpiration(exp time.Duration) redisOption {
return func(cfg *configRedis) {
cfg.expiration = exp
}
}
// Setup initializes redis cache for application. Must be called only once.
func (rc *RedisCache) Setup(addr, password, prefix string, db int, exp time.Duration) {
if rc == nil {
rc = new(RedisCache)
}
rc.Addr = addr
rc.Password = password
rc.DB = db
rc.Expiration = exp
rc.Prefix = prefix
opt := redis.Options{
Addr: addr,
Password: password,
DB: db,
}
rc.opt = &opt
rc.cli = redis.NewClient(&opt)
if _, err := rc.cli.Ping().Result(); err != nil {
// exit if connection to redis server fails
loggermdl.LogError("connection to redis server failed: ", err)
log.Fatal("connection to redis server failed: ", err)
}
rc.connected = true
if prefix != "" {
rc.keyStr = contcat(rc.Prefix, keySplitter)
rc.addPrefix = true
}
}
// SetupRedisCache initializes redis cache for application and returns it. Must be called only once.
func SetupRedisCache(opts ...redisOption) (*RedisCache, error) {
rc := new(RedisCache)
cfg := new(configRedis)
for i := range opts {
opts[i](cfg)
}
rc.Addr = cfg.addr
rc.Password = cfg.password
rc.DB = cfg.db
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rc.Expiration = cfg.expiration
rc.Prefix = cfg.prefix
rc.opt = &redis.Options{
Addr: cfg.addr,
Password: cfg.password,
DB: cfg.db,
}
rc.cli = redis.NewClient(rc.opt)
if _, err := rc.cli.Ping().Result(); err != nil {
return nil, errors.New("connection to redis server failed: " + err.Error())
}
rc.connected = true
if cfg.prefix != "" {
rc.keyStr = contcat(rc.Prefix, keySplitter)
rc.addPrefix = true
}
return rc, nil
}
// Set marshalls provided value and stores against provided key. Errors will be logged to initialized logger.
func (rc *RedisCache) Set(key string, val interface{}) {
ba, err := marshalWithTypeCheck(val)
if err != nil {
loggermdl.LogError("error setting key ", key, " error: ", err)
return
}
rc.cli.Set(rc.key(key), ba, rc.Expiration)
}
// SetWithExpiration marshalls provided value and stores against provided key for given duration. Errors will be logged to initialized logger.
func (rc *RedisCache) SetWithExpiration(key string, val interface{}, exp time.Duration) {
ba, err := marshalWithTypeCheck(val)
if err != nil {
loggermdl.LogError("error setting key ", key, " error: ", err)
return
}
rc.cli.Set(rc.key(key), ba, exp)
}
// SetNoExpiration marshalls provided value and stores against provided key.
// Errors will be logged to initialized logger.
func (rc *RedisCache) SetNoExpiration(key string, val interface{}) {
ba, err := marshalWithTypeCheck(val)
if err != nil {
loggermdl.LogError("error setting key ", key, " error: ", err)
return
}
rc.cli.Set(rc.key(key), ba, noExp)
}
// Get returns data against provided key. The final result is parsed with gjson. Returns false if not present.
func (rc *RedisCache) Get(key string) (interface{}, bool) {
// exists, err := rc.cli.Exists(key).Result()
// if err != nil {
// loggermdl.LogError("error checking key ", key, " error: ", err)
// return nil, false
// }
// if exists == NotOK {
// return nil, false
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// }
// Get returns error if key is not present.
val, err := rc.cli.Get(rc.key(key)).Result()
if err != nil {
loggermdl.LogError("error getting key", key, "from redis cache with error:", err)
return nil, false
}
return val, true
}
// Delete -
func (rc *RedisCache) Delete(key string) {
rc.cli.Del(rc.key(key)).Result()
}
// GetItemsCount -
func (rc *RedisCache) GetItemsCount() int {
pattern := rc.Prefix + "*"
keys, err := rc.cli.Keys(pattern).Result()
if err != nil {
loggermdl.LogError("error getting item count for ", pattern, " error: ", err)
return 0
}
return len(keys)
}
func (rc *RedisCache) flushDB() (string, error) {
return rc.cli.FlushDB().Result()
}
// Purge deletes for current redis db
func (rc *RedisCache) Purge() {
_, err := rc.flushDB()
if err != nil {
loggermdl.LogError("error purging redis cache for db ", rc.Addr, "/", rc.DB, " error: ", err)
}
}
func marshal(v interface{}) ([]byte, error) {
return json.Marshal(v)
}
// marshalWithTypeCheck checks type before marshsal. Save allocations and time significantly if the existing data is string or []byte
func marshalWithTypeCheck(v interface{}) ([]byte, error) {
switch d := v.(type) {
default:
return json.Marshal(v)
case string:
return []byte(d), nil
case []byte:
return d, nil
}
}
func contcat(s ...string) string {
sb := strings.Builder{}
for i := range s {
sb.WriteString(s[i])
}
return sb.String()
}
func (rc *RedisCache) key(key string) string {
// prepare in format "<Prefix>:<key>"
if rc.addPrefix {
return contcat(rc.keyStr, key)
}
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return key
}
func (rc *RedisCache) Type() int {
return TypeRedisCache
}
// GetAll returns all keys with values present in redis server. Excludes the keys which does not have specified prefix. If prefix is empty, then returns all keys.
//
// **This is not intended for production use. May hamper performance**
func (rc *RedisCache) GetAll() map[string]interface{} {
pattern := rc.Prefix + "*"
keys, err := rc.cli.Keys(pattern).Result()
if err != nil {
loggermdl.LogError("error getting keys for ", pattern, " error: ", err)
return nil
}
result := make(map[string]interface{}, len(keys))
for i := range keys {
ba, err := rc.cli.Get(keys[i]).Bytes()
if err != nil {
loggermdl.LogError("error getting key", keys[i], "from redis cache with error:", err)
continue
}
var val interface{}
_ = json.Unmarshal(ba, &val)
// accessing [1] won't panic as we have all keys with matching regex
result[strings.Split(keys[i], keySplitter)[1]] = val
}
return result
}