github.com/charlienet/go-mixed@v0.3.7/cache/cache.go (about)

     1  package cache
     2  
     3  import (
     4  	"context"
     5  	"errors"
     6  	"fmt"
     7  	"time"
     8  
     9  	"github.com/charlienet/go-mixed/bytesconv"
    10  	"github.com/charlienet/go-mixed/locker"
    11  	"github.com/charlienet/go-mixed/logx"
    12  )
    13  
    14  var ErrNotFound = errors.New("key not found")
    15  
    16  type LoadFunc func(context.Context) (any, error)
    17  
    18  type Cache struct {
    19  	prefix           string            // 键前缀
    20  	retry            int               // 资源获取时的重试次数
    21  	mem              MemCache          // 内存缓存
    22  	distributdCache  DistributdCache   // 分布式缓存
    23  	publishSubscribe PublishSubscribe  // 发布订阅
    24  	lock             locker.ChanLocker // 资源锁
    25  	qps              *qps              // 访问计数
    26  	logger           logx.Logger       // 日志记录
    27  }
    28  
    29  func NewCache(opts ...option) *Cache {
    30  
    31  	c := acquireDefaultCache()
    32  	for _, f := range opts {
    33  		if err := f(c); err != nil {
    34  			return c
    35  		}
    36  	}
    37  
    38  	go c.subscribe()
    39  
    40  	return c
    41  }
    42  
    43  func (c *Cache) Set(key string, value any, expiration time.Duration) error {
    44  	if c.mem != nil {
    45  		bytes, err := bytesconv.Encode(value)
    46  		if err != nil {
    47  			return err
    48  		}
    49  
    50  		c.mem.Set(key, bytes, expiration)
    51  	}
    52  
    53  	return nil
    54  }
    55  
    56  func (c *Cache) Get(key string, out any) error {
    57  	if c.mem != nil {
    58  		c.getFromMem(key, out)
    59  	}
    60  
    61  	if c.distributdCache != nil {
    62  		if err := c.distributdCache.Get(key, out); err != nil {
    63  
    64  		}
    65  	}
    66  
    67  	return nil
    68  }
    69  
    70  func (c *Cache) GetFn(ctx context.Context, key string, out any, fn LoadFunc, expiration time.Duration) (bool, error) {
    71  	c.Get(key, out)
    72  
    73  	// 多级缓存中未找到时,放置缓存对象
    74  	ret, err := fn(ctx)
    75  	if err != nil {
    76  		return false, err
    77  	}
    78  
    79  	c.Set(key, ret, expiration)
    80  
    81  	return false, nil
    82  }
    83  
    84  func (c *Cache) Exist(key string) (bool, error) {
    85  	return false, nil
    86  }
    87  
    88  func (c *Cache) Delete(key ...string) error {
    89  	if c.mem != nil {
    90  		c.mem.Delete(key...)
    91  	}
    92  
    93  	if c.distributdCache != nil {
    94  		c.distributdCache.Delete(key...)
    95  	}
    96  
    97  	return nil
    98  }
    99  
   100  func (c *Cache) subscribe() {
   101  }
   102  
   103  func (c *Cache) getFromMem(key string, out any) error {
   104  	bytes, err := c.mem.Get(key)
   105  	if err != nil {
   106  		return err
   107  	}
   108  
   109  	if err := bytesconv.Decode(bytes, out); err != nil {
   110  		return err
   111  	}
   112  
   113  	return nil
   114  }
   115  
   116  // 从缓存加载数据
   117  func (c *Cache) getFromCache() {
   118  	// 从缓存加载数据
   119  	// 1. 检查内存是否存在
   120  	// 2. 检查分布缓存是否存在
   121  }
   122  
   123  // 从数据源加载数据
   124  func (c *Cache) getFromSource(ctx context.Context, key string, fn LoadFunc) error {
   125  
   126  	// 1. 尝试获取资源锁，如成功获取到锁加载数据
   127  	// 2. 未获取到锁，等待从缓存中获取
   128  	ch, ok := c.lock.Get(key)
   129  	if ok {
   130  		defer c.lock.Release(key)
   131  
   132  		v, err := fn(ctx)
   133  		if err != nil {
   134  			return fmt.Errorf("load from source err:%v", err)
   135  		}
   136  
   137  		// 取出值存入多级缓存
   138  		_ = v
   139  
   140  		return nil
   141  	}
   142  
   143  	// 等待数据加载完成
   144  	select {
   145  	case <-ch:
   146  
   147  		// 未取到结果时，再次获取
   148  		return c.getFromSource(ctx, key, fn)
   149  	}
   150  }