Go unmarshal JSON with unknown field name but known struct

I retrieve a acme.json from traefik tls where traefik stores ssl/tls certificate information.

Now I want to unmarshal with golang the acme.json into my go struct "Traefik". But I don't know how to handle dynamic/unknown json field names because certificateresolver1 and certificateresolver2 are names I don't know at compile time. These names should be dynamic configured in go.

I know the structure of the json (it is always the same) but not know the field name of the certificateresolver.

Does anyone know the best way to do this?

Traefik acme.json

{
  "certificateresolver1": {
    "Account": {
      "Email": "email@example.com",
      "Registration": {
        "body": {
          "status": "valid",
          "contact": [
            "mailto:email@example.com"
          ]
        },
        "uri": "https://acme-v02.api.letsencrypt.org/acme/acct/124448363"
      },
      "PrivateKey": "PRIVATEKEY",
      "KeyType": "4096"
    },
    "Certificates": [
      {
        "domain": {
          "main": "example.com",
          "sans": [
            "test.example.com"
          ]
        },
        "certificate": "CERTIFICATE",
        "key": "KEY",
        "Store": "default"
      },
      {
        "domain": {
          "main": "example.org"
        },
        "certificate": "CERTIFICATE",
        "key": "KEY",
        "Store": "default"
      }
    ]
  },
  "certificateresolver2": {
    "Account": {
      "Email": "email@example.com",
      "Registration": {
        "body": {
          "status": "valid",
          "contact": [
            "mailto:email@example.com"
          ]
        },
        "uri": "https://acme-v02.api.letsencrypt.org/acme/acct/126945414"
      },
      "PrivateKey": "PRIVATEKEY",
      "KeyType": "4096"
    },
    "Certificates": [
      {
        "domain": {
          "main": "example.net"
        },
        "certificate": "CERTIFICATE",
        "key": "KEY",
        "Store": "default"
      }
    ]
  }
}

Go struct for acme.json

type Traefik struct {
	Provider []struct {
		Account struct {
			Email        string `json:"Email"`
			Registration struct {
				Body struct {
					Status  string   `json:"status"`
					Contact []string `json:"contact"`
				} `json:"body"`
				URI string `json:"uri"`
			} `json:"Registration"`
			PrivateKey string `json:"PrivateKey"`
			KeyType    string `json:"KeyType"`
		} `json:"Account"`
		Certificates []struct {
			Domain struct {
				Main string   `json:"main"`
				Sans []string `json:"sans"`
			} `json:"domain"`
			Certificate string `json:"certificate"`
			Key         string `json:"key"`
			Store       string `json:"Store"`
		} `json:"Certificates"`
	} `json:"certificateresolver"` <-- What to write there? It should fit for certificateresolver1 and certificateresolver2
}

I think something like this will help you:

type ProviderMdl map[string]Provider

type Provider struct {
	Account struct {
		Email        string `json:"Email"`
		Registration struct {
			Body struct {
				Status  string   `json:"status"`
				Contact []string `json:"contact"`
			} `json:"body"`
			URI string `json:"uri"`
		} `json:"Registration"`
		PrivateKey string `json:"PrivateKey"`
		KeyType    string `json:"KeyType"`
	} `json:"Account"`
	Certificates []struct {
		Domain struct {
			Main string   `json:"main"`
			Sans []string `json:"sans"`
		} `json:"domain"`
		Certificate string `json:"certificate"`
		Key         string `json:"key"`
		Store       string `json:"Store"`
	} `json:"Certificates"`
}

So you could work with this data in this way:

	bres := new(ProviderMdl)
	if err := json.Unmarshal(data, bres); err != nil {
		panic(err)
	}
	
	// fmt.Printf("%+v - \n", bres)

	for key, value := range *bres {
		fmt.Printf("%v - %v\n", key, value)
	}

Full example here