We are now going to define the structure of our assets, which will be recorded onto the ledger. In Go, the assets are defined as struct types with a list of attribute names and types. The definitions also need to contain JSON attribute names, which will be used to serialize the assets into the JSON objects. In the following snippet, you will see definitions for four assets in our application. Note that, the attributes of structs can encapsulate other structs and thus allow to create multi-level trees.

type TradeAgreement struct { 
   Amount                    int               `json:"amount"` 
   DescriptionOfGoods        string            `json:"descriptionOfGoods"` 
   Status                    string            `json:"status"` 
   Payment                   int               `json:"payment"` 
} 
 
type LetterOfCredit struct { 
   Id                        string            `json:"id"` 
   ExpirationDate            string            `json:"expirationDate"` 
   Beneficiary               string            `json:"beneficiary"` 
   Amount                    int               `json:"amount"` 
   Documents                 []string          `json:"documents"` 
   Status                    string            `json:"status"` 
} 
 
type ExportLicense struct { 
   Id                        string            `json:"id"` 
   ExpirationDate            string            `json:"expirationDate"` 
   Exporter                  string            `json:"exporter"` 
   Carrier                   string            `json:"carrier"` 
   DescriptionOfGoods        string            `json:"descriptionOfGoods"` 
   Approver                  string            `json:"approver"` 
   Status                    string            `json:"status"` 
} 
 
type BillOfLading struct { 
   Id                        string            `json:"id"` 
   ExpirationDate            string            `json:"expirationDate"` 
   Exporter                  string            `json:"exporter"` 
   Carrier                   string            `json:"carrier"` 
   DescriptionOfGoods        string            `json:"descriptionOfGoods"` 
   Amount                    int               `json:"amount"` 
   Beneficiary               string            `json:"beneficiary"` 
   SourcePort                string            `json:"sourcePort"` 
   DestinationPort           string            `json:"destinationPort"` 
}