几乎重复我自己

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

In this case it is not lots of code, but it is still bugging me. I have a shared problem, that is when trying to connect to an IP, if it fails, I should retry with the next IP.

I have one function which generates a producer for NSQ:

//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
    }
}

The other function that almost shares the same code is one which takes a NSQ consumer and connects it:

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

I would like to get rid of this almost repeated code without sacrificing legibility. Ideas?

Answer 1

You have it backwards. Your solution should follow the shape of the problem, not the shape of a particular solution. There's nothing in the solution that's worth refactoring. It's just going to add pointless complexity.

For example,

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() {}