/
oracle.go
126 lines (111 loc) · 3.71 KB
/
oracle.go
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package priceposter
import (
"context"
"crypto/rand"
"fmt"
"math/big"
oracletypes "github.com/NibiruChain/nibiru/x/oracle/types"
"github.com/NibiruChain/pricefeeder/types"
sdk "github.com/cosmos/cosmos-sdk/types"
"github.com/rs/zerolog"
)
var (
// MaxSaltNumber is the maximum salt number we can use for randomness.
// NOTE: max length of the salt is 4.
// TODO(mercilex): if we used digits + alphanumerics it's more randomized
MaxSaltNumber = big.NewInt(9999) // NOTE(mercilex): max salt length is 4
)
func vote(
ctx context.Context,
newPrevote, oldPrevote *prevote,
validator sdk.ValAddress,
feeder sdk.AccAddress,
deps deps,
logger zerolog.Logger,
) (txResponse *sdk.TxResponse, err error) {
// if oldPrevote is not nil then we need to get the vote msg
var voteMsg *oracletypes.MsgAggregateExchangeRateVote
if oldPrevote != nil {
voteMsg, err = prepareVote(ctx, deps.oracleClient, validator, feeder, oldPrevote, logger)
if err != nil {
return nil, err
}
logger.Info().Interface("vote", voteMsg).Msg("prepared vote message")
}
// once we prepared the vote msg we can send the tx
var msgs = []sdk.Msg{newPrevote.msg}
// if there was a vote then we of course need to vote first and then prevote.
if voteMsg != nil {
// note ordering matters because the new prevote will overwrite the old one
msgs = []sdk.Msg{voteMsg, newPrevote.msg}
} else {
logger.Info().Msg("skipping vote preparation as there is no old prevote")
}
return sendTx(
ctx, deps.keyBase, deps.authClient, deps.txClient,
feeder, deps.txConfig, deps.ir, deps.chainID, msgs...,
)
}
func prepareVote(
ctx context.Context,
oracleClient Oracle,
validator sdk.ValAddress, feeder sdk.AccAddress,
prevote *prevote,
logger zerolog.Logger,
) (*oracletypes.MsgAggregateExchangeRateVote, error) {
log := logger.With().Str("stage", "prepare-vote").Logger()
// there might be cases where due to downtimes the prevote
// has expired. So we check if a prevote exists in the chain, if it does not
// then we simply return.
resp, err := oracleClient.AggregatePrevote(ctx, &oracletypes.QueryAggregatePrevoteRequest{
ValidatorAddr: validator.String(),
})
if err != nil {
log.Err(err).Msg("failed to get aggregate prevote from chain")
return nil, nil
}
// assert equality between feeder's prevote and chain's prevote
if localHash := oracletypes.GetAggregateVoteHash(prevote.salt, prevote.vote, validator).String(); localHash != resp.AggregatePrevote.Hash {
log.Warn().Str("chain hash", resp.AggregatePrevote.Hash).Str("local hash", localHash).Msg("chain and local prevote do not match")
return nil, nil
}
return &oracletypes.MsgAggregateExchangeRateVote{
Salt: prevote.salt,
ExchangeRates: prevote.vote,
Feeder: feeder.String(),
Validator: validator.String(),
}, nil
}
type prevote struct {
msg *oracletypes.MsgAggregateExchangeRatePrevote
salt string
vote string
}
func newPrevote(prices []types.Price, validator sdk.ValAddress, feeder sdk.AccAddress) *prevote {
tuple := make(oracletypes.ExchangeRateTuples, len(prices))
for i, price := range prices {
tuple[i] = oracletypes.ExchangeRateTuple{
Pair: price.Pair,
ExchangeRate: float64ToDec(price.Price),
}
}
votesStr, err := tuple.ToString()
if err != nil {
panic(err)
}
nBig, err := rand.Int(rand.Reader, MaxSaltNumber)
if err != nil {
panic(err)
}
salt := nBig.String()
hash := oracletypes.GetAggregateVoteHash(salt, votesStr, validator)
return &prevote{
msg: oracletypes.NewMsgAggregateExchangeRatePrevote(hash, feeder, validator),
salt: salt,
vote: votesStr,
}
}
func float64ToDec(price float64) sdk.Dec {
// TODO(mercilex): precision for numbers with a lot of decimal digits
return sdk.MustNewDecFromStr(fmt.Sprintf("%f", price))
}