几乎在重复自己

Question

Combinitorial Explosion You have lots of code that does almost the same thing.. but with tiny variations in data or behavior. This can be difficult to refactor-- perhaps using generics or an interpreter? - Jeff Atwood via Coding Horror

在这种情况下，代码并不多，但它仍然困扰着我。我有一个共同的问题，那就是当尝试连接到一个 IP 时，如果失败，我应该用下一个 IP 重试。

我有一个函数可以为 NSQ 生成生产者：

//Since we are in a critical system, we try with each IP until we get a producer
var err error
for i, success := 0, false; i < len(ips) && !success; i++ {
    publisher, err = nsq.NewProducer(ips[i], nsq.NewConfig())
    if err == nil {
        success = true
    }
}

另一个几乎共享相同代码的函数是接受 NSQ 消费者并连接它的函数：

var err error
for i, success := 0, false; i < len(ips) && !success; i++ {
    err = consumer.ConnectToNSQD(ips[i])
    if err == nil {
        success = true
    }
}

我想在不牺牲易读性的情况下摆脱这段几乎重复的代码。想法？

Answer 1

也许是这样的？

var publisher *nsq.Producer

connectToWorkingIP(ips, func(ip string) error {
    var err error
    publisher, err = nsq.NewProducer(ip, nsq.NewConfig())
    return err
})

connectToWorkingIP(ips, func(ip string) error {
    return consumer.ConnectToNSQD(ip)
})


func connectToWorkingIP(ips []string, f func(string) error) {
    for i, success := 0, false; i < len(ips) && !success; i++ {
        err := f(ips[i])
        if err == nil {
            success = true
        }
    }
}

Answer 2

你搞反了。您的解决方案应该遵循问题的形式，而不是特定解决方案的形式。解决方案中没有任何东西值得重构。它只会增加毫无意义的复杂性。

例如，

package main

import "github.com/nsqio/go-nsq"

// NewProducer is nsq.NewProducer with retries of an address list.
func NewProducer(addrs []string, config *nsq.Config) (producer *nsq.Producer, err error) {
    if len(addrs) == 0 {
        addrs = append(addrs, "")
    }
    for _, addr := range addrs {
        producer, err = nsq.NewProducer(addr, config)
        if err == nil {
            break
        }
    }
    return producer, err
}

// ConnectToNSQD is nsq.ConnectToNSQD with retries of an address list.
func ConnectToNSQD(c *nsq.Consumer, addrs []string) (err error) {
    if len(addrs) == 0 {
        addrs = append(addrs, "")
    }
    for _, addr := range addrs {
        err = c.ConnectToNSQD(addr)
        if err == nil {
            break
        }
    }
    return err
}

func main() {}

几乎在重复自己

Almost Repeating Myself

refactoring

go