Optimize the GetInt() method of config

[fnoopv]

Because integers in json are not always asserted to be of type int
i have config.json

{
  ...
  "redis": {
    "host": "127.0.0.1",
    "port": 6379
  }
}

when i get redis.port

redisAddress := fmt.Sprintf("%s:%d", s.Config().GetString("redis.host"), s.Config().GetInt("redis.port"))

the program will panic panic: config entry "redis.port" is not an int.

so, I modified GetInt():

func (c *Config) GetInt(key string) int {

	+ fmt.Printf("value: '%v'\n", c.Get(key))
	+ t := reflect.TypeOf(c.Get(key))
	+ fmt.Printf("type: '%s'\n", t.String())

	val, ok := c.Get(key).(int)
	if !ok {
		panic(errors.Errorf("config entry \"%s\" is not an int", key))
	}
	return val
}

and got the output

value: '6379'
type: 'string'

Obviously, its type is string. But string can be converted to int type by using the strconv library method, like this

func (c *Config) GetInt(key string) int {
	switch v := c.Get(key).(type) {
	case int:
		return v
	case string:
		intVal, err := strconv.Atoi(v)
		if err == nil {
			return intVal
		}
	default:
		panic(errors.Errorf("config entry \"%s\" is not an int", key))
	}
	return 0
}

If the value type is int, it is returned directly. If the value type is string, it attempts to convert it. If successful, it returns the converted value, otherwise it throws a panic. I tried it in my application and it was successful

[System-Glitch]

Hello and thank you for your suggestion! You may not know about this, but this is already a feature:

goyave/config/entry.go

Line 83 in f9a153a

func (e *Entry) tryConversion(kind reflect.Kind) bool {

When the config is loaded, the types of each entry, if eligible, is converted to its expected type as defined in the config.Entry. This is why it is recommended to register the expected configuration entries using config.Register.

I invite you to participate to this discussion that suggests an even better solution that would leverage the much more powerful validation system.

[fnoopv]

Thanks for your reply. That's great, maybe we can add some prompts when panic error, prompting users to use Custom configuration entries

[System-Glitch]

I don't want to introduce error messages that would be too verbose. This behavior is documented but it may not be clear enough. If you have ideas as to how we could improve it, feel free to share them!

[fnoopv]

It should be stated that custom configuration entries should be used when type conversion to the target type fails. Maybe a link to this discussion can also be added to this section of the documentation or some sample code can be added. If you think it's ok, I can add it

[System-Glitch]

config.Register should always be used when you need any configuration entry that is not part of the default ones. I will think about how to add this notion to the documentation. Thank you for bringing this up!

[System-Glitch]

I added a callout with the following message:

Unregistered configuration entries can still be loaded. However, their type will be automatically determined based on the value parsed from the configuration file. To take advantage of the validation and conversion system, as well as ensuring that your custom entries have the type you expect, you should always register them using config.Register().