惯用的，否则为地图密钥链

I have a fairly long else if chain looking for keys in a map and setting a specific value if found. The way I chose to do it with the least amount of code was this (m is a map[string]interface{})

var ok bool
var s interface{}
if s, ok = m["key1"]; ok {
} else if s, ok = m["key2"]; ok {
           ....
} else if s, ok = m["keyN"]; ok {
} else {
   return RuhRohError
}
g.Id = s.(string)

This feels kinda clunky, I am doing all of these else if's to set a variable in the condition. Is there an idiomatic way to do this? I think this way doesn't make it immediately obvious what I am trying to do.

For example,

package main

import "fmt"

func findValue(m map[string]interface{}, keys []string) (interface{}, bool) {
    for _, key := range keys {
        if value, ok := m[key]; ok {
            return value, true
        }
    }
    return nil, false
}

func main() {
    m := map[string]interface{}{"keyn": "valuen"}
    keys := []string{"key1", "key2", "keyn"}
    s, found := findValue(m, keys)
    if !found {
        return
    }
    id := s.(string)
    fmt.Println(id)
}

Output:

valuen

Actually I think the code you provided is very easy to read and understand. It is a bit verbose but there is no magic ;). So if there is only one place where you have to write this code I would leave it as it is. If you need to write it a few times I would consider writing findValue function mentioned in another comment.