> func NewServer(... config *Config ...) http.Handler one of my biggest pet peeves is when people take a Config object, which represents the configuration of an entire system, and pass it around mutably. When you do that, you're coupling everything together through the config object. I've worked on systems where you had to configure the parts in a specific order in order for things to work, because someone decided to…
My favorite way to prevent this is to make the config truly immutable, but still configurable with something like this:
package config
type options struct {
name string
}
type Option func(o *options)
func Name(name string) Option {
return func(o *options) {
o.name = name
}
}
type Config struct {
opts *options
}
func New(opts ...Option) *Config {
o := &options{}
for _, option := range opts {
option(o)
}
return &Config{opts: o}
}
func (c *Config) Name() string {
return c.opts.name
}
cfg := config.New(config.Name("Emanon"))
fmt.Println(cfg.Name())