copy data from one golang slice struct to another slice strcut

Hi I have json data which I Unmarshal tomachines slice . Now I am looking to copy/append each hostname from machines slice struct to service Struct []hosts . I have tried few methods but struggling to iterate over []hosts slice in service struct .

Just wondering what is the best way to copy the value from one slice struct to another slice value inside some other struct.

package main

import (
	"encoding/json"
	"fmt"
)

type Machine struct {
	hostname  string
	Ip   string
	Name string
}

type Host struct {
	HostName string `json:"host_name"`
	Vars Var `json:"vars"`
}

type Service struct {
	ServiceName string `json:"service_name"`
	Required    bool   `json:"required"`
	Hosts       []Host `json:"hosts"`
	Vars        Var    `json:"vars"`
}


func main() {
	machineInfo := `[{"dns":"1.1.1.1.eu-south-1.compute.amazonaws.com","ip":"1.1.1.1","name":"Machine-1"},{"dns":"1.1.1.2.eu-south-1.compute.amazonaws.com","ip":"1.1.1.2","name":"Machine-2"}]`

	var machines []Machine
	var mService *Service
	//convert the json to byts slice and then

	json.Unmarshal([]byte(machineInfo), &machines)

	//Data is now add to the structs



	for i, _ := range machines {
		mService.Hosts = append(mService.Hosts, machines[i].hostname)
	}
	fmt.Printf("Machines : %v", mService)
	
	data, _ := json.Marshal(mService)


	fmt.Println(string(data))
}

Let's take it from the top:

Export the hostname field by capitalizing it. The JSON decoder ignores unexpected fields. Also, add a tag so the field matches the document:

type Machine struct {
	Hostname string `json:"name"`
	Ip       string
	Name     string
}

Declare mServices as a value to avoid nil pointer panic:

var mService Service

Use a composite literal expression to create a host for append to the slice:

	mService.Hosts = append(mService.Hosts, Host{HostName: machines[i].Hostname})

https://go.dev/play/p/nTBVwM3l9Iw