debug pool

redis_client.go

package main

import (
	"context"
	"fmt"
	"github.com/gomodule/redigo/redis"
	"sync"
	"sync/atomic"
	"time"
)

type mock struct {
	id        int64
	sleepTime time.Duration
	closed    bool
}

func (m mock) Close() error {
	fmt.Printf("%d: closed\n", m.id)
	return nil
}

func (mock) Err() error {
	return nil
}

func (m mock) Do(commandName string, args ...interface{}) (reply interface{}, err error) {
	if m.closed {
		panic("don't do if you closed")
	}
	time.Sleep(m.sleepTime)
	fmt.Printf("%d: done doing\n", m.id)
	return nil, nil
}

func (mock) Send(commandName string, args ...interface{}) error {
	panic("implement me")
}

func (mock) Flush() error {
	panic("implement me")
}

func (mock) Receive() (reply interface{}, err error) {
	panic("implement me")
}

var id int64

func main() {

	pool := redis.Pool{
		MaxActive: 3,
		MaxIdle:   100,
		Wait:      true,
		Dial: func() (conn redis.Conn, e error) {
			id := atomic.AddInt64(&id, 1)
			fmt.Printf("%d: connecting\n", id)
			return mock{id, time.Second * 2, false}, nil
		},
	}

	var nWorkers = 30
	var wg sync.WaitGroup
	wg.Add(nWorkers)

	for i := 0; i < nWorkers; i++ {
		go func() {
			defer wg.Done()

			conn, err := pool.GetContext(context.Background())
			if err != nil {
				panic(err)
			}

			_, err = conn.Do("MGET", "something")
			if err != nil {
				panic(err)
			}
			defer conn.Close()
		}()
	}

	wg.Wait()
}