if序列可以更优美地编写吗？ [关闭]

Question

if v, ok := os.LookupEnv("IDAASHTTPPORT"); ok {
    c.HTTPPort, _ = strconv.Atoi(v)
}
if v, ok := os.LookupEnv("IDAASDBNAME"); ok {
    c.DBUserName = v
}
if v, ok := os.LookupEnv("IDAASDBPW"); ok {
    c.DBPasswd = v
}
if v, ok := os.LookupEnv("IDAASDBPORT"); ok {
    c.DBPort, _ = strconv.Atoi(v)
}
if v, ok := os.LookupEnv("IDAASDBHOST"); ok {
    c.DBHost = v
}

'c' is the following struct

type Configuration struct {
    HTTPPort   int
    DBUserName string
    DBPasswd   string
    DBPort     int
    DBHost     string
}

I only want to update the struct field if the environment variable exists. Seems like some little cute map iterator or something like that would work, but I can't figure out a nice solution.

Answer 1

You can use some helper functions:

func setIntFromEnv(val *int, envName string) {
  if v, ok := os.LookupEnv(envName); ok {
    *val, _ = strconv.Atoi(v)
  }
}

func setStringFromEnv(val *string, envName string) {
  if v, ok := os.LookupEnv(envName); ok {
    *val = v
  }
}

// From your main function.
setIntFromEnv(&c.HTTPPort, "IDAASHTTPPORT")
setStringFromEnv(&c.DBUserName, "IDAASDBNAME")
etc...

This only works if you're ok ignoring a string env var that you're trying to parse as an int. Its relative elegance is also debatable.