Fix getFreeToken blocking issue

node/contract.go

@@ -4,6 +4,7 @@ import (
 	"crypto/ecdsa"
 	"math/big"
 	"strings"
+	"sync/atomic"
 
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/common"
@@ -170,8 +171,8 @@ func (node *Node) CallFaucetContract(address common.Address) common.Hash {
 }
 
 func (node *Node) callGetFreeToken(address common.Address) common.Hash {
-	nonce := node.GetNonceOfAddress(crypto.PubkeyToAddress(node.ContractDeployerKey.PublicKey))
-	return node.callGetFreeTokenWithNonce(address, nonce)
+	nonce := atomic.AddUint64(&node.ContractDeployerCurrentNonce, 1)
+	return node.callGetFreeTokenWithNonce(address, nonce-1)
 }
 
 func (node *Node) callGetFreeTokenWithNonce(address common.Address, nonce uint64) common.Hash {

node/node.go

@@ -144,9 +144,10 @@ type Node struct {
 	Address    common.Address
 
 	// For test only
-	TestBankKeys        []*ecdsa.PrivateKey
-	ContractDeployerKey *ecdsa.PrivateKey
-	ContractAddresses   []common.Address
+	TestBankKeys                 []*ecdsa.PrivateKey
+	ContractDeployerKey          *ecdsa.PrivateKey
+	ContractDeployerCurrentNonce uint64 // The nonce of the deployer contract at current block
+	ContractAddresses            []common.Address
 
 	// Shard group Message Receiver
 	shardGroupReceiver p2p.GroupReceiver

node/node_handler.go

@@ -11,9 +11,12 @@ import (
 	"os"
 	"os/exec"
 	"strconv"
+	"sync/atomic"
 	"syscall"
 	"time"
 
+	"github.com/ethereum/go-ethereum/crypto"
+
 	"github.com/harmony-one/harmony/core"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -315,6 +318,10 @@ func (node *Node) PostConsensusProcessing(newBlock *types.Block) {
 
 	node.AddNewBlock(newBlock)
 
+	// Update contract deployer's nonce so default contract like faucet can issue transaction with current nonce
+	nonce := node.GetNonceOfAddress(crypto.PubkeyToAddress(node.ContractDeployerKey.PublicKey))
+	atomic.StoreUint64(&node.ContractDeployerCurrentNonce, nonce)
+
 	if node.Consensus.ShardID == 0 {
 
 		// ConfirmedBlockChannel which is listened by drand leader who will initiate DRG if its a epoch block (first block of a epoch)