Create generic struct that implements substructs

Im a bit newer to golang and struggle to make this work.
I create a generic structure with some subtypes in form of payloads.

type Item struct {
payload Payload
}

type Payload struct {
Name: String
}

type SubscriptionPayload struct {
subscriptionId string
payload
}

type ResourcePayload struct{
resourceId string 
payload
}

My goal would be that I can generate items where the payload contains both the common and specific attributes of the payload structs. So for example
item1 := {"payload": {"name": "subscription1", "subscriptionId": "1234}
item2 := {"payload": {"name": "resource1", "resourceId": "5678"}

I thought by passing the payload as an attribute in the subtype this would inherit the payload attributes, but then my problem is that I cant pass the subtype directly as a value for payload inside the item.

i think y want something there, its classic

type Item struct {
	Payload Payload
}

type Payload struct {
	Name string
	*SubscriptionPayload
	*ResourcePayload
}

type SubscriptionPayload struct {
	SubscriptionId string
}

type ResourcePayload struct{
	ResourceId string
}

or y may asking of constraint struct, ex: (not recomended, if y new in go)

type QuotaType interface {
	Quota | []any
}

type Quota struct {
	Limit      uint64

}

type GeneralQuota[T QuotaInterface] struct {
	Id         string
	Bytes      *T
	Keys       *T
}

func main() {
	var q Quota
	var gq GeneralQuota[Quota]
	gq.Keys = &q
}

and previosly coment about ifaces good and work too

You may want to use interface instead! An interface type is defined as a set of method signatures. A value of interface type can hold any value that implements those methods.

type Item struct {
	Payload IPayload
}

type IPayload interface {
	GetName() string
}

type Payload struct {
	Name string
}

func (p *Payload) GetName() string { return p.Name }

type SubscriptionPayload struct {
	SubscriptionId string
	Payload
}

type ResourcePayload struct {
	ResourceId string
	Payload
}

A Tour of Go

One way you can handle this is by defining an interface for the common part (i.e., the Payload struct). This interface can be as simple as the following or you can include more functionality based on the common behavior.

type Payloader interface {
	GetPayloadName() string
}

All your structs that include payload struct will automatically get the interface implementation. Then, since each Item.payload implements this interface, you can perform a type assertion to get the concrete type. Below is a complete implementation for the example you provided.

package main

import "fmt"

func main() {
	var item Item

	item = Item{
		payload: &SubscriptionPayload{
			subscriptionId: "1234",
			Payload: Payload{
				Name: "subscription1",
			},
		},
	}
	fmt.Println(item.payload.GetPayloadName())
	if subsPayl, ok := item.payload.(*SubscriptionPayload); ok {
		fmt.Println(subsPayl.subscriptionId)
	}

	item = Item{
		payload: &ResourcePayload{
			resourceId: "5678",
			Payload: Payload{
				Name: "resource1",
			},
		},
	}
	fmt.Println(item.payload.GetPayloadName())
	if subsPayl, ok := item.payload.(*ResourcePayload); ok {
		fmt.Println(subsPayl.resourceId)
	}
}

type Item struct {
	payload Payloader
}

type Payload struct {
	Name string
}

func (p *Payload) GetPayloadName() string {
	return p.Name
}

type SubscriptionPayload struct {
	subscriptionId string
	Payload
}

type ResourcePayload struct {
	resourceId string
	Payload
}

type Payloader interface {
	GetPayloadName() string
}

Since the type is defined based on the Payload.Name and we can get this value using the Payloader interface, you can define a switch code block to perform proper actions based on the Payload.Name.