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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,129 @@ | ||
| package lcw | ||
|
|
||
| import ( | ||
| "sync/atomic" | ||
| "time" | ||
|
|
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| redis "github.com/go-redis/redis/v7" | ||
| "github.com/pkg/errors" | ||
| ) | ||
|
|
||
| // RedisSizeLimit is maximum allowed value size in Redis | ||
| const RedisSizeLimit = 512 * 1024 * 1024 | ||
|
|
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| // RedisCache implements LoadingCache for Redis. | ||
| type RedisCache struct { | ||
| options | ||
| CacheStat | ||
| backend *redis.Client | ||
| } | ||
|
|
||
| // NewRedisCache makes Redis LoadingCache implementation. | ||
| func NewRedisCache(backend *redis.Client, opts ...Option) (*RedisCache, error) { | ||
|
|
||
| res := RedisCache{ | ||
| options: options{ | ||
| ttl: 5 * time.Minute, | ||
| }, | ||
| } | ||
| for _, opt := range opts { | ||
| if err := opt(&res.options); err != nil { | ||
| return nil, errors.Wrap(err, "failed to set cache option") | ||
| } | ||
| } | ||
|
|
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| res.backend = backend | ||
|
|
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| return &res, nil | ||
| } | ||
|
|
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| // Get gets value by key or load with fn if not found in cache | ||
| func (c *RedisCache) Get(key string, fn func() (Value, error)) (data Value, err error) { | ||
|
|
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| v, getErr := c.backend.Get(key).Result() | ||
| switch getErr { | ||
| case nil: | ||
| atomic.AddInt64(&c.Hits, 1) | ||
| return v, nil | ||
| case redis.Nil: | ||
| if data, err = fn(); err != nil { | ||
| atomic.AddInt64(&c.Errors, 1) | ||
| return data, err | ||
| } | ||
| default: | ||
| atomic.AddInt64(&c.Errors, 1) | ||
| return v, getErr | ||
| } | ||
| atomic.AddInt64(&c.Misses, 1) | ||
|
|
||
| if c.allowed(key, data) { | ||
| c.backend.Set(key, data, c.ttl) | ||
| } | ||
| return data, nil | ||
| } | ||
|
|
||
| // Invalidate removes keys with passed predicate fn, i.e. fn(key) should be true to get evicted | ||
| func (c *RedisCache) Invalidate(fn func(key string) bool) { | ||
| for _, key := range c.backend.Keys("*").Val() { // Keys() returns copy of cache's key, safe to remove directly | ||
| if fn(key) { | ||
| c.backend.Del(key) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // Peek returns the key value (or undefined if not found) without updating the "recently used"-ness of the key. | ||
| func (c *RedisCache) Peek(key string) (Value, bool) { | ||
| ret, err := c.backend.Get(key).Result() | ||
| if err != nil { | ||
| return nil, false | ||
| } | ||
| return ret, true | ||
| } | ||
|
|
||
| // Purge clears the cache completely. | ||
| func (c *RedisCache) Purge() { | ||
| c.backend.FlushDB() | ||
|
|
||
| } | ||
|
|
||
| // Delete cache item by key | ||
| func (c *RedisCache) Delete(key string) { | ||
| c.backend.Del(key) | ||
| } | ||
|
|
||
| // Stat returns cache statistics | ||
| func (c *RedisCache) Stat() CacheStat { | ||
| return CacheStat{ | ||
| Hits: c.Hits, | ||
| Misses: c.Misses, | ||
| Size: c.size(), | ||
| Keys: c.keys(), | ||
| Errors: c.Errors, | ||
| } | ||
| } | ||
|
|
||
| func (c *RedisCache) size() int64 { | ||
| return 0 | ||
| } | ||
|
|
||
| func (c *RedisCache) keys() int { | ||
| return int(c.backend.DBSize().Val()) | ||
| } | ||
|
|
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| func (c *RedisCache) allowed(key string, data Value) bool { | ||
| if c.backend.DBSize().Val() >= int64(c.maxKeys) { | ||
| return false | ||
| } | ||
| if c.maxKeySize > 0 && len(key) > c.maxKeySize { | ||
| return false | ||
| } | ||
| if s, ok := data.(Sizer); ok { | ||
| if c.maxValueSize > 0 && (s.Size() >= c.maxValueSize || s.Size() >= RedisSizeLimit) { | ||
| return false | ||
| } | ||
| if c.maxValueSize <= 0 && s.Size() >= RedisSizeLimit { | ||
| return false | ||
| } | ||
| } | ||
| return true | ||
| } |