fix (braking change): gas refill params (#89)

NOTE: This needs the db to be nuked if you are running a test cluster

* updated gas refilling logic to reflect EthFaucet contract
* fully dependant on on-chain contract to refill and unlock gas
* minor fixes to nonce bootstrapper

Ideal Values:

INITIAL GIFT = 0.015
THRESHOLD    = 0.01
TIME = 12 * 60 * 60

# Sample for 30 txs
EXTREME LOW = 0.00675
LOW GAS USAGE = 0.00694605
RISING = 0.0135
HIGH = 0.027

cmd/service/main.go

@@ -60,6 +60,7 @@ func main() {
 	custodial, err := custodial.NewCustodial(custodial.Opts{
 		CeloProvider:     celoProvider,
 		LockProvider:     lockProvider,
+		Logg:             lo,
 		Noncestore:       redisNoncestore,
 		Store:            store,
 		RedisClient:      redisPool.Client,

internal/api/sign.go

@@ -13,6 +13,7 @@ import (
 )
 
 // HandleSignTransfer godoc
+//
 //	@Summary		Sign and dispatch transfer request.
 //	@Description	Sign and dispatch a transfer request.
 //	@Tags			network
@@ -42,7 +43,7 @@ func HandleSignTransfer(cu *custodial.Custodial) func(echo.Context) error {
 			return err
 		}
 
-		accountActive, gasQuota, err := cu.Store.GetAccountStatus(c.Request().Context(), req.From)
+		accountActive, gasLock, err := cu.Store.GetAccountStatus(c.Request().Context(), req.From)
 		if err != nil {
 			return err
 		}
@@ -54,36 +55,15 @@ func HandleSignTransfer(cu *custodial.Custodial) func(echo.Context) error {
 			})
 		}
 
-		trackingId := uuid.NewString()
+		if gasLock {
-
-		if gasQuota < 1 {
-			gasRefillPayload, err := json.Marshal(task.AccountPayload{
-				PublicKey:  req.From,
-				TrackingId: trackingId,
-			})
-			if err != nil {
-				return err
-			}
-
-			_, err = cu.TaskerClient.CreateTask(
-				c.Request().Context(),
-				tasker.AccountRefillGasTask,
-				tasker.DefaultPriority,
-				&tasker.Task{
-					Id:      trackingId,
-					Payload: gasRefillPayload,
-				},
-			)
-			if err != nil {
-				return err
-			}
-
 			return c.JSON(http.StatusForbidden, ErrResp{
 				Ok:      false,
-				Message: "Out of gas, refill pending. Try again later.",
+				Message: "Gas lock. Gas balance unavailable. Try again later.",
 			})
 		}
 
+		trackingId := uuid.NewString()
+
 		taskPayload, err := json.Marshal(task.TransferPayload{
 			TrackingId:     trackingId,
 			From:           req.From,

internal/custodial/custodial.go

@@ -15,12 +15,14 @@ import (
 	"github.com/grassrootseconomics/w3-celo-patch"
 	"github.com/labstack/gommon/log"
 	"github.com/redis/go-redis/v9"
+	"github.com/zerodha/logf"
 )
 
 type (
 	Opts struct {
 		CeloProvider     *celoutils.Provider
 		LockProvider     *redislock.Client
+		Logg             logf.Logger
 		Noncestore       nonce.Noncestore
 		Store            store.Store
 		RedisClient      *redis.Client
@@ -54,11 +56,13 @@ func NewCustodial(o Opts) (*Custodial, error) {
 		return nil, err
 	}
 
-	_, err = o.Noncestore.Peek(ctx, o.SystemPublicKey)
+	systemNonce, err := o.Noncestore.Peek(ctx, o.SystemPublicKey)
 	if err != nil {
 		return nil, err
 	}
 
+	o.Logg.Info("custodial: loaded_nonce", "system_nonce", systemNonce)
+
 	privateKey, err := eth_crypto.HexToECDSA(o.SystemPrivateKey)
 	if err != nil {
 		return nil, err

internal/nonce/redis.go

@@ -37,14 +37,18 @@ func NewRedisNoncestore(o Opts) Noncestore {
 
 func (n *RedisNoncestore) Peek(ctx context.Context, publicKey string) (uint64, error) {
 	nonce, err := n.redis.Client.Get(ctx, publicKey).Uint64()
+	if err != nil {
 		if err == redis.Nil {
 			nonce, err = n.bootstrap(ctx, publicKey)
 			if err != nil {
 				return 0, err
 			}
-	} else if err != nil {
+
+			return nonce, nil
+		} else {
 			return 0, err
 		}
+	}
 
 	return nonce, nil
 }
@@ -55,14 +59,16 @@ func (n *RedisNoncestore) Acquire(ctx context.Context, publicKey string) (uint64
 	)
 
 	nonce, err := n.redis.Client.Get(ctx, publicKey).Uint64()
+	if err != nil {
 		if err == redis.Nil {
 			nonce, err = n.bootstrap(ctx, publicKey)
 			if err != nil {
 				return 0, err
 			}
-	} else if err != nil {
+		} else {
 			return 0, err
 		}
+	}
 
 	err = n.redis.Client.Incr(ctx, publicKey).Err()
 	if err != nil {

internal/store/account.go

@@ -22,10 +22,10 @@ func (s *PgStore) ActivateAccount(
 func (s *PgStore) GetAccountStatus(
 	ctx context.Context,
 	publicAddress string,
-) (bool, int, error) {
+) (bool, bool, error) {
 	var (
 		accountActive bool
-		gasQuota      int
+		gasLock       bool
 	)
 
 	if err := s.db.QueryRow(
@@ -34,21 +34,21 @@ func (s *PgStore) GetAccountStatus(
 		publicAddress,
 	).Scan(
 		&accountActive,
-		&gasQuota,
+		&gasLock,
 	); err != nil {
-		return false, 0, err
+		return false, false, err
 	}
 
-	return accountActive, gasQuota, nil
+	return accountActive, gasLock, nil
 }
 
-func (s *PgStore) DecrGasQuota(
+func (s *PgStore) GasLock(
 	ctx context.Context,
 	publicAddress string,
 ) error {
 	if _, err := s.db.Exec(
 		ctx,
-		s.queries.DecrGasQuota,
+		s.queries.GasLock,
 		publicAddress,
 	); err != nil {
 		return err
@@ -57,13 +57,13 @@ func (s *PgStore) DecrGasQuota(
 	return nil
 }
 
-func (s *PgStore) ResetGasQuota(
+func (s *PgStore) GasUnlock(
 	ctx context.Context,
 	publicAddress string,
 ) error {
 	if _, err := s.db.Exec(
 		ctx,
-		s.queries.ResetGasQuota,
+		s.queries.GasUnlock,
 		publicAddress,
 	); err != nil {
 		return err

internal/store/store.go

@@ -27,10 +27,10 @@ type (
 		UpdateDispatchStatus(context.Context, bool, string, uint64) error
 		// Account related actions.
 		ActivateAccount(context.Context, string) error
-		GetAccountStatus(context.Context, string) (bool, int, error)
+		GetAccountStatus(context.Context, string) (bool, bool, error)
 		// Gas quota related actions.
-		DecrGasQuota(context.Context, string) error
+		GasLock(context.Context, string) error
-		ResetGasQuota(context.Context, string) error
+		GasUnlock(context.Context, string) error
 	}
 
 	Opts struct {
@@ -57,8 +57,8 @@ type (
 		// Account related queries.
 		ActivateAccount  string `query:"activate-account"`
 		GetAccountStatus string `query:"get-account-status-by-address"`
-		DecrGasQuota     string `query:"decr-gas-quota"`
+		GasLock          string `query:"acc-gas-lock"`
-		ResetGasQuota    string `query:"reset-gas-quota"`
+		GasUnlock        string `query:"acc-gas-unlock"`
 	}
 )
 

internal/sub/handler.go

@@ -45,11 +45,11 @@ func (s *Sub) processEventHandler(ctx context.Context, msg *nats.Msg) error {
 				return err
 			}
 
-			if err := s.cu.Store.ResetGasQuota(ctx, chainEvent.To); err != nil {
+			if err := s.cu.Store.GasUnlock(ctx, chainEvent.To); err != nil {
 				return err
 			}
 		case "CHAIN.gas":
-			if err := s.cu.Store.ResetGasQuota(ctx, chainEvent.To); err != nil {
+			if err := s.cu.Store.GasUnlock(ctx, chainEvent.To); err != nil {
 				return err
 			}
 		}

internal/tasker/task/account_refill_gas.go

@@ -35,16 +35,6 @@ func AccountRefillGasProcessor(cu *custodial.Custodial) func(context.Context, *a
 			return err
 		}
 
-		_, gasQuota, err := cu.Store.GetAccountStatus(ctx, payload.PublicKey)
-		if err != nil {
-			return err
-		}
-
-		// The user has enough gas for atleast 5 more transactions.
-		if gasQuota > 5 {
-			return nil
-		}
-
 		if err := cu.CeloProvider.Client.CallCtx(
 			ctx,
 			eth.CallFunc(
@@ -56,8 +46,8 @@ func AccountRefillGasProcessor(cu *custodial.Custodial) func(context.Context, *a
 			return err
 		}
 
-		// The user already requested funds, there is a cooldown applied.
+		// The user recently requested funds, there is a cooldown applied.
-		// We can schedule an attempt after the cooldown period has passed.
+		// We can schedule an attempt after the cooldown period has passed + 10 seconds.
 		if nextTime.Int64() > time.Now().Unix() {
 			_, err = cu.TaskerClient.CreateTask(
 				ctx,
@@ -66,7 +56,7 @@ func AccountRefillGasProcessor(cu *custodial.Custodial) func(context.Context, *a
 				&tasker.Task{
 					Payload: t.Payload(),
 				},
-				asynq.ProcessAt(time.Unix(nextTime.Int64(), 0)),
+				asynq.ProcessAt(time.Unix(nextTime.Int64()+10, 0)),
 			)
 			if err != nil {
 				return err
@@ -130,6 +120,7 @@ func AccountRefillGasProcessor(cu *custodial.Custodial) func(context.Context, *a
 				InputData:       input,
 				GasFeeCap:       celoutils.SafeGasFeeCap,
 				GasTipCap:       celoutils.SafeGasTipCap,
+				GasLimit:        gasLimit,
 				Nonce:           nonce,
 			},
 		)

internal/tasker/task/sign_transfer.go

@@ -12,6 +12,7 @@ import (
 	"github.com/grassrootseconomics/cic-custodial/internal/store"
 	"github.com/grassrootseconomics/cic-custodial/internal/tasker"
 	"github.com/grassrootseconomics/cic-custodial/pkg/enum"
+	"github.com/grassrootseconomics/w3-celo-patch/module/eth"
 	"github.com/hibiken/asynq"
 )
 
@@ -27,6 +28,7 @@ func SignTransfer(cu *custodial.Custodial) func(context.Context, *asynq.Task) er
 	return func(ctx context.Context, t *asynq.Task) error {
 		var (
 			err            error
+			networkBalance big.Int
 			payload        TransferPayload
 		)
 
@@ -105,7 +107,10 @@ func SignTransfer(cu *custodial.Custodial) func(context.Context, *asynq.Task) er
 			return err
 		}
 
-		if err := cu.Store.DecrGasQuota(ctx, payload.From); err != nil {
+		if err := cu.CeloProvider.Client.CallCtx(
+			ctx,
+			eth.Balance(celoutils.HexToAddress(payload.From), nil).Returns(&networkBalance),
+		); err != nil {
 			return err
 		}
 
@@ -137,6 +142,11 @@ func SignTransfer(cu *custodial.Custodial) func(context.Context, *asynq.Task) er
 			return err
 		}
 
+		if !balanceCheck(networkBalance) {
+			if err := cu.Store.GasLock(ctx, payload.From); err != nil {
+				return err
+			}
+
 			_, err = cu.TaskerClient.CreateTask(
 				ctx,
 				tasker.AccountRefillGasTask,
@@ -148,6 +158,7 @@ func SignTransfer(cu *custodial.Custodial) func(context.Context, *asynq.Task) er
 			if err != nil {
 				return err
 			}
+		}
 
 		return nil
 	}

internal/tasker/task/utils.go

@@ -1,6 +1,7 @@
 package task
 
 import (
+	"math/big"
 	"time"
 
 	"github.com/bsm/redislock"
@@ -14,6 +15,15 @@ const (
 	lockTimeout    = 1 * time.Second
 )
 
+var (
+	// 20 gwei = max gas price we are willing to pay
+	// 250k = max gas limit
+	// minGasBalanceRequired is optimistic that the immidiate next transfer request will be successful
+	// but the subsequent one could fail (though low probability), therefore we can trigger a gas lock.
+	// Therefore our system wide threshold is 0.01 CELO or 10000000000000000 gas units
+	minGasBalanceRequired = big.NewInt(20000000000 * 250000 * 2)
+)
+
 // lockRetry will at most try to obtain the lock 20 times within ~0.5s.
 // it is expected to prevent immidiate requeue of the task at the expense of more redis calls.
 func lockRetry() redislock.RetryStrategy {
@@ -22,3 +32,8 @@ func lockRetry() redislock.RetryStrategy {
 		20,
 	)
 }
+
+// balanceCheck compares the network balance with the system set min as threshold to execute a transfer.
+func balanceCheck(networkBalance big.Int) bool {
+	return minGasBalanceRequired.Cmp(&networkBalance) < 0
+}

migrations/005_remove_gas_quota.sql

@@ -0,0 +1,34 @@
+-- Replace gas_quota with gas_lock which checks network balance threshold 
+DROP TRIGGER IF EXISTS update_gas_quota_timestamp ON gas_quota;
+DROP TABLE IF EXISTS gas_quota_meta;
+DROP TABLE IF EXISTS gas_quota;
+DROP TRIGGER IF EXISTS insert_gas_quota ON keystore;
+DROP FUNCTION IF EXISTS insert_gas_quota;
+
+-- Gas lock table
+-- A gas_locked account indicates gas balance is below threshold awaiting next available top up
+CREATE TABLE IF NOT EXISTS gas_lock (
+    id INT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+    key_id INT REFERENCES keystore(id) NOT NULL,
+    lock BOOLEAN DEFAULT true,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+create function insert_gas_lock()
+    returns trigger
+as $$
+begin
+    insert into gas_lock (key_id) values (new.id);
+    return new;
+end;
+$$ language plpgsql;
+
+create trigger insert_gas_lock
+    after insert on keystore
+for each row
+execute procedure insert_gas_lock();
+
+create trigger update_gas_lock_timestamp
+    before update on gas_lock
+for each row
+execute procedure update_timestamp();

queries.sql

@@ -73,27 +73,24 @@ UPDATE otx_dispatch SET "status" = $2, "block" = $3 WHERE otx_dispatch.id = (
 UPDATE keystore SET active = true WHERE public_key=$1
 
 --name: get-account-status-by-address
--- Gets current gas quota for an individual account by address
+-- Gets current gas lock and activation status for an individual account by address
 -- $1: public_key
-SELECT keystore.active, gas_quota.quota FROM keystore
+SELECT keystore.active, gas_lock.lock FROM keystore
-INNER JOIN gas_quota ON keystore.id = gas_quota.key_id
+INNER JOIN gas_lock ON keystore.id = gas_lock.key_id
 WHERE keystore.public_key=$1
 
---name: decr-gas-quota
+--name: acc-gas-lock
--- Consumes a gas quota
+-- Locks an account for gas reasons
 -- $1: public_key
-UPDATE gas_quota SET quota = quota - 1 WHERE key_id = (
+UPDATE gas_lock SET lock = true WHERE key_id = (
     SELECT id FROM keystore
     WHERE public_key=$1    
 )
 
---name: reset-gas-quota
+--name: acc-gas-unlock
--- Resets the gas quota
+-- Unlocks an account for gas reasons
--- 25 is the agreed upon quota
 -- $1: public_key
-UPDATE gas_quota SET quota = gas_quota_meta.default_quota
+UPDATE gas_lock SET lock = false WHERE key_id = (
-FROM gas_quota_meta
-WHERE key_id = (
     SELECT id FROM keystore
     WHERE public_key=$1    
 )