github.com/mdaxf/iac@v0.0.0-20240519030858-58a061660378/framework/cache/random_expired_cache.go (about)

     1  // The package is migrated from beego, you can get from following link:
     2  // import(
     3  //   "github.com/beego/beego/v2/client/cache"
     4  // )
     5  // Copyright 2023. All Rights Reserved.
     6  //
     7  // Licensed under the Apache License, Version 2.0 (the "License");
     8  // you may not use this file except in compliance with the License.
     9  // You may obtain a copy of the License at
    10  //
    11  //      http://www.apache.org/licenses/LICENSE-2.0
    12  //
    13  // Unless required by applicable law or agreed to in writing, software
    14  // distributed under the License is distributed on an "AS IS" BASIS,
    15  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    16  // See the License for the specific language governing permissions and
    17  // limitations under the License.
    18  
    19  package cache
    20  
    21  import (
    22  	"context"
    23  	"math/rand"
    24  	"sync/atomic"
    25  	"time"
    26  )
    27  
    28  // RandomExpireCacheOption implement genreate random time offset expired option
    29  type RandomExpireCacheOption func(*RandomExpireCache)
    30  
    31  // WithRandomExpireOffsetFunc returns a RandomExpireCacheOption that configures the offset function
    32  func WithRandomExpireOffsetFunc(fn func() time.Duration) RandomExpireCacheOption {
    33  	return func(cache *RandomExpireCache) {
    34  		cache.offset = fn
    35  	}
    36  }
    37  
    38  // RandomExpireCache prevent cache batch invalidation
    39  // Cache random time offset expired
    40  type RandomExpireCache struct {
    41  	Cache
    42  	offset func() time.Duration
    43  }
    44  
    45  // Put random time offset expired
    46  func (rec *RandomExpireCache) Put(ctx context.Context, key string, val interface{}, timeout time.Duration) error {
    47  	timeout += rec.offset()
    48  	return rec.Cache.Put(ctx, key, val, timeout)
    49  }
    50  
    51  // NewRandomExpireCache return random expire cache struct
    52  func NewRandomExpireCache(adapter Cache, opts ...RandomExpireCacheOption) Cache {
    53  	rec := RandomExpireCache{
    54  		Cache:  adapter,
    55  		offset: defaultExpiredFunc(),
    56  	}
    57  	for _, fn := range opts {
    58  		fn(&rec)
    59  	}
    60  	return &rec
    61  }
    62  
    63  // defaultExpiredFunc return a func that used to generate random time offset (range: [3s,8s)) expired
    64  func defaultExpiredFunc() func() time.Duration {
    65  	const size = 5
    66  	var randTimes [size]time.Duration
    67  	for i := range randTimes {
    68  		randTimes[i] = time.Duration(i+3) * time.Second
    69  	}
    70  	// shuffle values
    71  	for i := range randTimes {
    72  		n := rand.Intn(size)
    73  		randTimes[i], randTimes[n] = randTimes[n], randTimes[i]
    74  	}
    75  	var i uint64
    76  	return func() time.Duration {
    77  		return randTimes[atomic.AddUint64(&i, 1)%size]
    78  	}
    79  }