updatecache

README

updatecache

Overview

The purpose of updatecache is to update the cache conveniently. When executing a query to the backend to update the cache, other query coroutines can choose to wait for the query to complete or directly use the value in the current cache.

Install

go get github.com/vearne/updatecache

Use environment variables to set log level

optional value: debug | info | warn | error

export SIMPLE_LOG_LEVEL=debug

Unit Test

go test .
go test -v .
go test -run TestFirstLoad ./

Example

package main

import (
	cache "github.com/vearne/updatecache"
	"log"
	"sync/atomic"
	"time"
)

func calcuDuration(value any) time.Duration {
	return time.Second
}

func main() {
	key := "aaa"
	c := cache.NewCache(true)
	var counter uint32 = 2
	if !c.Contains(key) {
		result := c.FirstLoad(key,
			1,
			func() (any, error) {
				time.Sleep(time.Second)
				log.Println("FirstLoad-GetValueFunc")
				return 2, nil
			},
			10*time.Second)
		c.DynamicUpdateLater(key, calcuDuration, func() (any, error) {
			// get value from backend(for example: MySQL, MongoDB or other application)
			log.Println("get value from backend...")
			return atomic.AddUint32(&counter, 1), nil
		})
		log.Printf("result:%v \n", result)
	}
	for i := 0; i < 30; i++ {
		time.Sleep(500 * time.Millisecond)
		log.Println(c.Get(key))
	}

}

Documentation

Index

• type AtomicBool
  • func NewAtomicBool(flag bool) *AtomicBool
  • func (ab *AtomicBool) IsSet() bool
  • func (ab *AtomicBool) IsTrue() bool
  • func (ab *AtomicBool) Set(value bool)
• type CalcTimeForNextUpdateFunc
• type GetValueFunc
• type Item
  • func NewItem(key, value any) *Item
• type LocalCache
  • func NewCache(waitUpdate bool) *LocalCache
  • func (c *LocalCache) Contains(key any) (ok bool)
  • func (c *LocalCache) DynamicUpdateLater(key any, cf CalcTimeForNextUpdateFunc, gf GetValueFunc)
  • func (c *LocalCache) FirstLoad(key any, defaultValue any, gf GetValueFunc, d time.Duration) any
  • func (c *LocalCache) Get(key any) any
  • func (c *LocalCache) Remove(key any)
  • func (c *LocalCache) Set(key any, value any, d time.Duration)
  • func (c *LocalCache) SetIfNotExist(key any, value any, d time.Duration)
  • func (c *LocalCache) Size() int
  • func (c *LocalCache) StopLaterUpdate(key any)
  • func (c *LocalCache) UpdateLater(key any, d time.Duration, getValueFunc GetValueFunc)

Types

type AtomicBool

type AtomicBool struct {
	// contains filtered or unexported fields
}

atomicBool is a wrapper around uint32 for usage as a boolean value with atomic access.

func NewAtomicBool

func NewAtomicBool(flag bool) *AtomicBool

func (*AtomicBool) IsSet

func (ab *AtomicBool) IsSet() bool

IsSet returns whether the current boolean value is true

func (*AtomicBool) IsTrue

func (ab *AtomicBool) IsTrue() bool

func (*AtomicBool) Set

func (ab *AtomicBool) Set(value bool)

Set sets the value of the bool regardless of the previous value

type CalcTimeForNextUpdateFunc

type CalcTimeForNextUpdateFunc func(value any) time.Duration

Calculate the waiting time until the next data update

type GetValueFunc

type GetValueFunc func() (value any, err error)

type Item

type Item struct {
	// contains filtered or unexported fields
}

func NewItem

func NewItem(key, value any) *Item

type LocalCache

type LocalCache struct {
	// contains filtered or unexported fields
}

func NewCache

func NewCache(waitUpdate bool) *LocalCache

func (*LocalCache) Contains

func (c *LocalCache) Contains(key any) (ok bool)

func (*LocalCache) DynamicUpdateLater

func (c *LocalCache) DynamicUpdateLater(key any, cf CalcTimeForNextUpdateFunc, gf GetValueFunc)

Notice: Item and CalcTimeForNextUpdateFunc, GetValueFunc will only be bound once. 1. Calculate the waiting time until the next data update with CalcTimeForNextUpdateFunc 2. then use GetValueFunc to get value 3. update item

func (*LocalCache) FirstLoad

func (c *LocalCache) FirstLoad(key any, defaultValue any, gf GetValueFunc, d time.Duration) any

func (*LocalCache) Get

func (c *LocalCache) Get(key any) any

func (*LocalCache) Remove

func (c *LocalCache) Remove(key any)

func (*LocalCache) Set

func (c *LocalCache) Set(key any, value any, d time.Duration)

If d is less than 0, the item does not expire

func (*LocalCache) SetIfNotExist

func (c *LocalCache) SetIfNotExist(key any, value any, d time.Duration)

If d is less than 0, the item does not expire

func (*LocalCache) Size

func (c *LocalCache) Size() int

func (*LocalCache) StopLaterUpdate

func (c *LocalCache) StopLaterUpdate(key any)

func (*LocalCache) UpdateLater

func (c *LocalCache) UpdateLater(key any, d time.Duration, getValueFunc GetValueFunc)

1. wait d 2. then use GetValueFunc to get value 3. update item