Go Standard Library Cookbook

How to do it...

1. Open the console and create the folder chapter01/recipe12.
2. Navigate to the directory.
3. Create the main.go file with the following content:

        package main        import (          "encoding/json"          "fmt"          "os"        )        type Client struct {          consulIP string          connString string        }        func (c *Client) String() string {          return fmt.Sprintf("ConsulIP: %s , Connection String: %s",                             c.consulIP, c.connString)        }        var defaultClient = Client{          consulIP: "localhost:9000",          connString: "postgres://localhost:5432",        }        // ConfigFunc works as a type to be used        // in functional options        type ConfigFunc func(opt *Client)        // FromFile func returns the ConfigFunc        // type. So this way it could read the configuration        // from the json.        func FromFile(path string) ConfigFunc { return func(opt ...