main.go

package main

import (
	"context"
	"fmt"
	"net"

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

type dialerFunc func(ctx context.Context, network, addr string) (net.Conn, error)

func makeDialer(errorCount int) dialerFunc {
	return func(ctx context.Context, network, addr string) (net.Conn, error) {
		if errorCount > 0 {
			errorCount--
			return nil, fmt.Errorf("kaboom")
		}
		return net.Dial(network, addr)
	}
}

func main() {
	ctx := context.Background()

	rdb1 := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Dialer:   makeDialer(1),
		PoolSize: 2,
	})
	rdb2 := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Dialer:   makeDialer(2),
		PoolSize: 2,
	})

	fmt.Println("With only one error, the client recovers:")
	for i := 0; i < 10; i++ {
		status, err := rdb1.Ping(ctx).Result()
		fmt.Printf("%d  status: %q, err: %v\n", i, status, err)
	}

	fmt.Println("But if we have >= PoolSize errors in a row, the client is broken forever:")
	for i := 0; i < 10; i++ {
		status, err := rdb2.Ping(ctx).Result()
		fmt.Printf("%d  status: %q, err: %v\n", i, status, err)
	}
}