Golang的几种限流 package的用法

package rlimit

import (
    "fmt"
    "log"
    "testing"
    "time"

    "go.uber.org/ratelimit"
)

func TestRatelimit(t *testing.T) {
    rl := ratelimit.New(5) // per second

    log.Println("begin")
    prev := time.Now()
    for i := 0; i < 20; i++ {
        now := rl.Take()
        if i > 0 {
            fmt.Println(time.Now().String(), i, now.Sub(prev))
        }
        prev = now
    }

    log.Println("end")
}

运行结果：

[@hbhly_x_128 rlimit]$ go test -v ./
=== RUN   TestRatelimit
2022/03/26 16:57:41 begin
2022-03-26 16:57:42.014050639 +0800 CST m=+0.201108898 1 200ms
2022-03-26 16:57:42.21436404 +0800 CST m=+0.401422303 2 200ms
2022-03-26 16:57:42.415431893 +0800 CST m=+0.602490176 3 200ms
2022-03-26 16:57:42.613796177 +0800 CST m=+0.800854436 4 200ms
2022-03-26 16:57:42.813946371 +0800 CST m=+1.001004630 5 200ms
2022-03-26 16:57:43.014065797 +0800 CST m=+1.201124062 6 200ms
2022-03-26 16:57:43.213814857 +0800 CST m=+1.400873126 7 200ms
2022-03-26 16:57:43.414051201 +0800 CST m=+1.601109480 8 200ms
2022-03-26 16:57:43.614073789 +0800 CST m=+1.801132054 9 200ms
2022-03-26 16:57:43.815042061 +0800 CST m=+2.002100350 10 200ms
2022-03-26 16:57:44.013803537 +0800 CST m=+2.200861788 11 200ms
2022-03-26 16:57:44.213911271 +0800 CST m=+2.400969542 12 200ms
2022-03-26 16:57:44.413809965 +0800 CST m=+2.600868262 13 200ms
2022-03-26 16:57:44.613820171 +0800 CST m=+2.800878444 14 200ms
2022-03-26 16:57:44.813841891 +0800 CST m=+3.000900180 15 200ms
2022-03-26 16:57:45.013852437 +0800 CST m=+3.200910702 16 200ms
2022-03-26 16:57:45.213788735 +0800 CST m=+3.400846994 17 200ms
2022-03-26 16:57:45.414422254 +0800 CST m=+3.601480515 18 200ms
2022-03-26 16:57:45.613828739 +0800 CST m=+3.800887038 19 200ms
2022/03/26 16:57:45 end
--- PASS: TestRatelimit (3.80s)
PASS
ok      demo/rlimit     3.805s

说明：New 函数限制了每秒的执行个数（5），所以每个请求间隔200ms，然后我们发现执行总个数（20）需要的时间（4s） 

package rlimit

func TestRateLimiter(t *testing.T) {

    // 第一个参数是r Limit。代表每秒可以向Token桶中产生多少token
    // Limit实际上是float64的别名。

    // 第二个参数是b int。b代表Token桶的容量大小。
    //limiter := NewLimiter(10, 1);

    // 除了直接指定每秒产生的Token个数外，还可以用Every方法来指定向Token桶中放置Token的间隔
    // 例如：表示每100ms往桶中放一个Token。本质上也就是一秒钟产生10个：
    limit := Every(100 * time.Millisecond);
    limiter := NewLimiter(limit, 1);
}

package redis_rate_test

import (
	"context"
	"fmt"

	"github.com/go-redis/redis/v8"
	"github.com/go-redis/redis_rate/v9"
)

func ExampleNewLimiter() {
	ctx := context.Background()
	rdb := redis.NewClient(&redis.Options{
		Addr: "localhost:6379",
	})
	_ = rdb.FlushDB(ctx).Err()

	limiter := redis_rate.NewLimiter(rdb)
	res, err := limiter.Allow(ctx, "project:123", redis_rate.PerSecond(10))
	if err != nil {
		panic(err)
	}
	fmt.Println("allowed", res.Allowed, "remaining", res.Remaining)
	// Output: allowed 1 remaining 9
}