0g-chain/x/auction/simulation/operations.go

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package simulation
import (
"errors"
"fmt"
"math/big"
"math/rand"
"time"
"github.com/cosmos/cosmos-sdk/baseapp"
"github.com/cosmos/cosmos-sdk/codec"
"github.com/cosmos/cosmos-sdk/simapp/helpers"
sdk "github.com/cosmos/cosmos-sdk/types"
"github.com/cosmos/cosmos-sdk/x/auth"
authexported "github.com/cosmos/cosmos-sdk/x/auth/exported"
"github.com/cosmos/cosmos-sdk/x/simulation"
appparams "github.com/kava-labs/kava/app/params"
"github.com/kava-labs/kava/x/auction/keeper"
"github.com/kava-labs/kava/x/auction/types"
)
var (
errorNotEnoughCoins = errors.New("account doesn't have enough coins")
errorCantReceiveBids = errors.New("auction can't receive bids (lot = 0 in reverse auction)")
)
// Simulation operation weights constants
const (
OpWeightMsgPlaceBid = "op_weight_msg_place_bid"
)
// WeightedOperations returns all the operations from the module with their respective weights
func WeightedOperations(
appParams simulation.AppParams, cdc *codec.Codec, ak auth.AccountKeeper, k keeper.Keeper,
) simulation.WeightedOperations {
var weightMsgPlaceBid int
appParams.GetOrGenerate(cdc, OpWeightMsgPlaceBid, &weightMsgPlaceBid, nil,
func(_ *rand.Rand) {
weightMsgPlaceBid = appparams.DefaultWeightMsgPlaceBid
},
)
return simulation.WeightedOperations{
simulation.NewWeightedOperation(
weightMsgPlaceBid,
SimulateMsgPlaceBid(ak, k),
),
}
}
// SimulateMsgPlaceBid returns a function that runs a random state change on the module keeper.
// There's two error paths
// - return a OpMessage, but nil error - this will log a message but keep running the simulation
// - return an error - this will stop the simulation
func SimulateMsgPlaceBid(ak auth.AccountKeeper, keeper keeper.Keeper) simulation.Operation {
return func(
r *rand.Rand, app *baseapp.BaseApp, ctx sdk.Context, accs []simulation.Account, chainID string,
) (simulation.OperationMsg, []simulation.FutureOperation, error) {
// get open auctions
openAuctions := types.Auctions{}
keeper.IterateAuctions(ctx, func(a types.Auction) bool {
openAuctions = append(openAuctions, a)
return false
})
// shuffle auctions slice so that bids are evenly distributed across auctions
r.Shuffle(len(openAuctions), func(i, j int) {
openAuctions[i], openAuctions[j] = openAuctions[j], openAuctions[i]
})
// search through auctions and accounts to find a pair where a bid can be placed (ie account has enough coins to place bid on auction)
blockTime := ctx.BlockHeader().Time
params := keeper.GetParams(ctx)
bidder, openAuction, found := findValidAccountAuctionPair(accs, openAuctions, func(acc simulation.Account, auc types.Auction) bool {
account := ak.GetAccount(ctx, acc.Address)
_, err := generateBidAmount(r, params, auc, account, blockTime)
if err == errorNotEnoughCoins || err == errorCantReceiveBids {
return false // keep searching
} else if err != nil {
panic(err) // raise errors
}
return true // found valid pair
})
if !found {
return simulation.NewOperationMsgBasic(types.ModuleName, "no-operation (no valid auction and bidder)", "", false, nil), nil, nil
}
bidderAcc := ak.GetAccount(ctx, bidder.Address)
if bidderAcc == nil {
return simulation.NoOpMsg(types.ModuleName), nil, fmt.Errorf("couldn't find account %s", bidder.Address)
}
// pick a bid amount for the chosen auction and bidder
amount, err := generateBidAmount(r, params, openAuction, bidderAcc, blockTime)
if err != nil { // shouldn't happen given the checks above
return simulation.NoOpMsg(types.ModuleName), nil, err
}
// create and deliver a tx
msg := types.NewMsgPlaceBid(openAuction.GetID(), bidder.Address, amount)
tx := helpers.GenTx(
[]sdk.Msg{msg},
sdk.NewCoins(), // TODO pick a random amount fees
helpers.DefaultGenTxGas,
chainID,
[]uint64{bidderAcc.GetAccountNumber()},
[]uint64{bidderAcc.GetSequence()},
bidder.PrivKey,
)
_, _, err = app.Deliver(tx)
if err != nil {
// to aid debugging, add the stack trace to the comment field of the returned opMsg
return simulation.NewOperationMsg(msg, false, fmt.Sprintf("%+v", err)), nil, err
}
return simulation.NewOperationMsg(msg, true, ""), nil, nil
}
}
func generateBidAmount(
r *rand.Rand, params types.Params, auc types.Auction,
bidder authexported.Account, blockTime time.Time,
) (sdk.Coin, error) {
bidderBalance := bidder.SpendableCoins(blockTime)
switch a := auc.(type) {
case types.DebtAuction:
// Check bidder has enough (stable coin) to pay in
if bidderBalance.AmountOf(a.Bid.Denom).LT(a.Bid.Amount) { // stable coin
return sdk.Coin{}, errorNotEnoughCoins
}
// Check auction can still receive new bids
if a.Lot.Amount.Equal(sdk.ZeroInt()) {
return sdk.Coin{}, errorCantReceiveBids
}
// Generate a new lot amount (gov coin)
maxNewLotAmt := a.Lot.Amount.Sub( // new lot must be some % less than old lot, and at least 1 smaller to avoid replacing an old bid at no cost
sdk.MaxInt(
sdk.NewInt(1),
sdk.NewDecFromInt(a.Lot.Amount).Mul(params.IncrementDebt).RoundInt(),
),
)
amt, err := RandIntInclusive(r, sdk.ZeroInt(), maxNewLotAmt) // maxNewLotAmt shouldn't be < 0 given the check above
if err != nil {
panic(err)
}
return sdk.NewCoin(a.Lot.Denom, amt), nil // gov coin
case types.SurplusAuction:
// Check the bidder has enough (gov coin) to pay in
minNewBidAmt := a.Bid.Amount.Add( // new bids must be some % greater than old bid, and at least 1 larger to avoid replacing an old bid at no cost
sdk.MaxInt(
sdk.NewInt(1),
sdk.NewDecFromInt(a.Bid.Amount).Mul(params.IncrementSurplus).RoundInt(),
),
)
if bidderBalance.AmountOf(a.Bid.Denom).LT(minNewBidAmt) { // gov coin
return sdk.Coin{}, errorNotEnoughCoins
}
// Generate a new bid amount (gov coin)
amt, err := RandIntInclusive(r, minNewBidAmt, bidderBalance.AmountOf(a.Bid.Denom))
if err != nil {
panic(err)
}
return sdk.NewCoin(a.Bid.Denom, amt), nil // gov coin
case types.CollateralAuction:
// Check the bidder has enough (stable coin) to pay in
minNewBidAmt := a.Bid.Amount.Add( // new bids must be some % greater than old bid, and at least 1 larger to avoid replacing an old bid at no cost
sdk.MaxInt(
sdk.NewInt(1),
sdk.NewDecFromInt(a.Bid.Amount).Mul(params.IncrementCollateral).RoundInt(),
),
)
minNewBidAmt = sdk.MinInt(minNewBidAmt, a.MaxBid.Amount) // allow new bids to hit MaxBid even though it may be less than the increment %
if bidderBalance.AmountOf(a.Bid.Denom).LT(minNewBidAmt) {
return sdk.Coin{}, errorNotEnoughCoins
}
// Check auction can still receive new bids
if a.IsReversePhase() && a.Lot.Amount.Equal(sdk.ZeroInt()) {
return sdk.Coin{}, errorCantReceiveBids
}
// Generate a new bid amount (collateral coin in reverse phase)
if a.IsReversePhase() {
maxNewLotAmt := a.Lot.Amount.Sub( // new lot must be some % less than old lot, and at least 1 smaller to avoid replacing an old bid at no cost
sdk.MaxInt(
sdk.NewInt(1),
sdk.NewDecFromInt(a.Lot.Amount).Mul(params.IncrementCollateral).RoundInt(),
),
)
amt, err := RandIntInclusive(r, sdk.ZeroInt(), maxNewLotAmt) // maxNewLotAmt shouldn't be < 0 given the check above
if err != nil {
panic(err)
}
return sdk.NewCoin(a.Lot.Denom, amt), nil // collateral coin
// Generate a new bid amount (stable coin in forward phase)
} else {
amt, err := RandIntInclusive(r, minNewBidAmt, sdk.MinInt(bidderBalance.AmountOf(a.Bid.Denom), a.MaxBid.Amount))
if err != nil {
panic(err)
}
// when the bidder has enough coins, pick the MaxBid amount more frequently to increase chance auctions phase get into reverse phase
if r.Intn(2) == 0 && bidderBalance.AmountOf(a.Bid.Denom).GTE(a.MaxBid.Amount) { // 50%
amt = a.MaxBid.Amount
}
return sdk.NewCoin(a.Bid.Denom, amt), nil // stable coin
}
default:
return sdk.Coin{}, fmt.Errorf("unknown auction type")
}
}
// findValidAccountAuctionPair finds an auction and account for which the callback func returns true
func findValidAccountAuctionPair(accounts []simulation.Account, auctions types.Auctions, cb func(simulation.Account, types.Auction) bool) (simulation.Account, types.Auction, bool) {
for _, auc := range auctions {
for _, acc := range accounts {
if isValid := cb(acc, auc); isValid {
return acc, auc, true
}
}
}
return simulation.Account{}, nil, false
}
// RandIntInclusive randomly generates an sdk.Int in the range [inclusiveMin, inclusiveMax]. It works for negative and positive integers.
func RandIntInclusive(r *rand.Rand, inclusiveMin, inclusiveMax sdk.Int) (sdk.Int, error) {
if inclusiveMin.GT(inclusiveMax) {
return sdk.Int{}, fmt.Errorf("min larger than max")
}
return RandInt(r, inclusiveMin, inclusiveMax.Add(sdk.OneInt()))
}
// RandInt randomly generates an sdk.Int in the range [inclusiveMin, exclusiveMax). It works for negative and positive integers.
func RandInt(r *rand.Rand, inclusiveMin, exclusiveMax sdk.Int) (sdk.Int, error) {
// validate input
if inclusiveMin.GTE(exclusiveMax) {
return sdk.Int{}, fmt.Errorf("min larger or equal to max")
}
// shift the range to start at 0
shiftedRange := exclusiveMax.Sub(inclusiveMin) // should always be positive given the check above
// randomly pick from the shifted range
shiftedRandInt := sdk.NewIntFromBigInt(new(big.Int).Rand(r, shiftedRange.BigInt()))
// shift back to the original range
return shiftedRandInt.Add(inclusiveMin), nil
}