如何从Go中的文件读取配置键/值对？

I have a low latency app in Node.js from which I am coding a new baseline in Go.

The app in node uses config and some key/value pairs.

In config/index.js

var config = {};
config.app = {
    port:9000
};
config.log= {
    level:"error"
}
module.exports=config;

And another file config/key_values.js which contains key/value pair and is refreshed every few minutes.

module.exports.key_values= {
"key1":"value1",
"key2":"value2",
}

And to read this I just use the below code.

let config = require('./config/index');
let keys_vals = require('./config/key_values.js');

console.log('port', config.app.port); //port 9000
console.log('key1 data -->', keys_vals.key_values['key1']); //key1 data --> value1 

How can I achieve the same thing in go. I have checked Gonfig for config implementation as well as building structs.

What should be better/best way to achieve the same functionalities as I do in Node?

OK. So here is what I have done for now. config/index.js is now config/config.json with content

{
    "app":{"port":9000},
    "log":{"level":"error"}
}

and config/key_values.js is config/key_values.json

{
    "key1":"value1",
    "key2":"value2"
}

And to read this value I am just reading file as []byte and passing the this to function GetBytes of library gjson

So the final code look like this:

    configFile, err := os.Open("config/config.json")
    byteValue, _ := ioutil.ReadAll(configFile)
    result := gjson.GetBytes(byteValue, "app.port")
    fmt.Println(result) //prints 9000

And same for key values file.

    configFile, err := os.Open("config/key_values.json")
    byteValue, _ := ioutil.ReadAll(configFile)
    result := gjson.GetBytes(byteValue, "key1")
    fmt.Println(result) //prints value1

Also tried using struct before to parse config as described here. But this gjson library seems to be what I was searching.