- 2019-08-30: initial draft
Currently, the Cosmos SDK allows for custom account types; the auth
keeper stores any type fulfilling its Account
interface. However auth
does not handle exporting or loading accounts to/from a genesis file, this is done by genaccounts
, which only handles one of 4 concrete account types (BaseAccount
, ContinuousVestingAccount
, DelayedVestingAccount
and ModuleAccount
).
Projects desiring to use custom accounts (say custom vesting accounts) need to fork and modify genaccounts
.
In summary, we will (un)marshal all accounts (interface types) directly using amino, rather than converting to genaccounts
’s GenesisAccount
type. Since doing this removes the majority of genaccounts
's code, we will merge genaccounts
into auth
. Marshalled accounts will be stored in auth
's genesis state.
Detailed changes:
The auth
module's GenesisState
gains a new field Accounts
. Note these aren't of type exported.Account
for reasons outlined in section 3.
// GenesisState - all auth state that must be provided at genesis
type GenesisState struct {
Params Params `json:"params" yaml:"params"`
Accounts []GenesisAccount `json:"accounts" yaml:"accounts"`
}
Now auth
's InitGenesis
and ExportGenesis
(un)marshal accounts as well as the defined params.
// InitGenesis - Init store state from genesis data
func InitGenesis(ctx sdk.Context, ak AccountKeeper, data GenesisState) {
ak.SetParams(ctx, data.Params)
// load the accounts
for _, a := range data.Accounts {
acc := ak.NewAccount(ctx, a) // set account number
ak.SetAccount(ctx, acc)
}
}
// ExportGenesis returns a GenesisState for a given context and keeper
func ExportGenesis(ctx sdk.Context, ak AccountKeeper) GenesisState {
params := ak.GetParams(ctx)
var genAccounts []exported.GenesisAccount
ak.IterateAccounts(ctx, func(account exported.Account) bool {
genAccount := account.(exported.GenesisAccount)
genAccounts = append(genAccounts, genAccount)
return false
})
return NewGenesisState(params, genAccounts)
}
The auth
codec must have all custom account types registered to marshal them. We will follow the pattern established in gov
for proposals.
An example custom account definition:
import authtypes "cosmossdk.io/x/auth/types"
// Register the module account type with the auth module codec so it can decode module accounts stored in a genesis file
func init() {
authtypes.RegisterAccountTypeCodec(ModuleAccount{}, "cosmos-sdk/ModuleAccount")
}
type ModuleAccount struct {
...
The auth
codec definition:
var ModuleCdc *codec.LegacyAmino
func init() {
ModuleCdc = codec.NewLegacyAmino()
// register module msg's and Account interface
...
// leave the codec unsealed
}
// RegisterAccountTypeCodec registers an external account type defined in another module for the internal ModuleCdc.
func RegisterAccountTypeCodec(o interface{}, name string) {
ModuleCdc.RegisterConcrete(o, name, nil)
}
Modules implement a ValidateGenesis
method. As auth
does not know of account implementations, accounts will need to validate themselves.
We will unmarshal accounts into a GenesisAccount
interface that includes a Validate
method.
type GenesisAccount interface {
exported.Account
Validate() error
}
Then the auth
ValidateGenesis
function becomes:
// ValidateGenesis performs basic validation of auth genesis data returning an
// error for any failed validation criteria.
func ValidateGenesis(data GenesisState) error {
// Validate params
...
// Validate accounts
addrMap := make(map[string]bool, len(data.Accounts))
for _, acc := range data.Accounts {
// check for duplicated accounts
addrStr := acc.GetAddress().String()
if _, ok := addrMap[addrStr]; ok {
return fmt.Errorf("duplicate account found in genesis state; address: %s", addrStr)
}
addrMap[addrStr] = true
// check account specific validation
if err := acc.Validate(); err != nil {
return fmt.Errorf("invalid account found in genesis state; address: %s, error: %s", addrStr, err.Error())
}
}
return nil
}
The genaccounts
module contains a cli command to add base or vesting accounts to a genesis file.
This will be moved to auth
. We will leave it to projects to write their own commands to add custom accounts. An extensible cli handler, similar to gov
, could be created but it is not worth the complexity for this minor use case.
Under the new scheme, module and vesting account types need some minor updates:
- Type registration on
auth
's codec (shown above) - A
Validate
method for eachAccount
concrete type
Proposed
- custom accounts can be used without needing to fork
genaccounts
- reduction in lines of code
genaccounts
module no longer exists- accounts in genesis files are stored under
accounts
inauth
rather than in thegenaccounts
module. -add-genesis-account
cli command now inauth