oracle: integrate module in core and RPC

1. Initialization is performed via `Blockchain` methods.
2. Native Oracle contract updates list of oracle nodes
  and in-fly requests in `PostPersist`.
3. RPC uses Oracle module directly.

cli/executor_test.go

@@ -80,7 +80,7 @@ func newTestChain(t *testing.T, f func(*config.Config)) (*core.Blockchain, *serv
 	netSrv, err := network.NewServer(serverConfig, chain, zap.NewNop())
 	require.NoError(t, err)
 	go netSrv.Start(make(chan error, 1))
-	rpcServer := server.New(chain, cfg.ApplicationConfiguration.RPC, netSrv, logger)
+	rpcServer := server.New(chain, cfg.ApplicationConfiguration.RPC, netSrv, nil, logger)
 	errCh := make(chan error, 2)
 	rpcServer.Start(errCh)
 

cli/server/server.go

@@ -319,7 +319,7 @@ func startServer(ctx *cli.Context) error {
 	if err != nil {
 		return cli.NewExitError(fmt.Errorf("failed to create network server: %w", err), 1)
 	}
-	rpcServer := server.New(chain, cfg.ApplicationConfiguration.RPC, serv, log)
+	rpcServer := server.New(chain, cfg.ApplicationConfiguration.RPC, serv, serv.GetOracle(), log)
 	errChan := make(chan error)
 
 	go serv.Start(errChan)

config/protocol.mainnet.yml

@@ -48,6 +48,9 @@ ApplicationConfiguration:
   MaxPeers: 100
   AttemptConnPeers: 20
   MinPeers: 5
+  Oracle:
+    Enabled: false
+
   RPC:
     Enabled: true
     MaxGasInvoke: 15

config/protocol.privnet.docker.four.yml

@@ -44,6 +44,17 @@ ApplicationConfiguration:
   MaxPeers: 10
   AttemptConnPeers: 5
   MinPeers: 3
+  Oracle:
+    Enabled: false
+    Nodes:
+      - 172.200.0.1:30333
+      - 172.200.0.2:30334
+      - 172.200.0.3:30335
+      - 172.200.0.4:30336
+    RequestTimeout: 5s
+    UnlockWallet:
+      Path: "/wallet4.json"
+      Password: "four"
   RPC:
     Enabled: true
     MaxGasInvoke: 15

config/protocol.privnet.docker.one.yml

@@ -44,6 +44,17 @@ ApplicationConfiguration:
   MaxPeers: 10
   AttemptConnPeers: 5
   MinPeers: 3
+  Oracle:
+    Enabled: false
+    Nodes:
+      - 172.200.0.1:30333
+      - 172.200.0.2:30334
+      - 172.200.0.3:30335
+      - 172.200.0.4:30336
+    RequestTimeout: 5s
+    UnlockWallet:
+      Path: "/wallet1.json"
+      Password: "one"
   RPC:
     Enabled: true
     MaxGasInvoke: 15

config/protocol.privnet.docker.single.yml

@@ -38,6 +38,14 @@ ApplicationConfiguration:
   MaxPeers: 10
   AttemptConnPeers: 5
   MinPeers: 0
+  Oracle:
+    Enabled: false
+    Nodes:
+      - 172.200.0.1:30333
+    RequestTimeout: 5s
+    UnlockWallet:
+      Path: "/wallet1_solo.json"
+      Password: "one"
   RPC:
     Enabled: true
     EnableCORSWorkaround: false

config/protocol.privnet.docker.three.yml

@@ -44,6 +44,17 @@ ApplicationConfiguration:
   MaxPeers: 10
   AttemptConnPeers: 5
   MinPeers: 3
+  Oracle:
+    Enabled: false
+    Nodes:
+      - 172.200.0.1:30333
+      - 172.200.0.2:30334
+      - 172.200.0.3:30335
+      - 172.200.0.4:30336
+    RequestTimeout: 5s
+    UnlockWallet:
+      Path: "/wallet3.json"
+      Password: "three"
   RPC:
     Enabled: true
     MaxGasInvoke: 15

config/protocol.privnet.docker.two.yml

@@ -44,6 +44,17 @@ ApplicationConfiguration:
   MaxPeers: 10
   AttemptConnPeers: 5
   MinPeers: 3
+  Oracle:
+    Enabled: false
+    Nodes:
+      - 172.200.0.1:30333
+      - 172.200.0.2:30334
+      - 172.200.0.3:30335
+      - 172.200.0.4:30336
+    RequestTimeout: 5s
+    UnlockWallet:
+      Path: "/wallet2.json"
+      Password: "two"
   RPC:
     Enabled: true
     MaxGasInvoke: 15

config/protocol.testnet.yml

@@ -48,6 +48,9 @@ ApplicationConfiguration:
   MaxPeers: 100
   AttemptConnPeers: 20
   MinPeers: 5
+  Oracle:
+    Enabled: false
+
   RPC:
     Enabled: true
     MaxGasInvoke: 15

pkg/config/application_config.go

@@ -26,4 +26,5 @@ type ApplicationConfiguration struct {
 	Relay             bool                    `yaml:"Relay"`
 	RPC               rpc.Config              `yaml:"RPC"`
 	UnlockWallet      Wallet                  `yaml:"UnlockWallet"`
+	Oracle            OracleConfiguration     `yaml:"Oracle"`
 }

pkg/config/oracle_config.go

@@ -0,0 +1,13 @@
+package config
+
+import "time"
+
+// OracleConfiguration is a config for the oracle module.
+type OracleConfiguration struct {
+	Enabled          bool          `yaml:"Enabled"`
+	AllowPrivateHost bool          `yaml:"AllowPrivateHost"`
+	Nodes            []string      `yaml:"Nodes"`
+	RequestTimeout   time.Duration `yaml:"RequestTimeout"`
+	ResponseTimeout  time.Duration `yaml:"ResponseTimeout"`
+	UnlockWallet     Wallet        `yaml:"UnlockWallet"`
+}

pkg/core/blockchain.go

@@ -14,6 +14,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
@@ -191,6 +192,13 @@ func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration, log *zap.L
 	return bc, nil
 }
 
+// SetOracle sets oracle module. It doesn't protected by mutex and
+// must be called before `bc.Run()` to avoid data race.
+func (bc *Blockchain) SetOracle(mod services.Oracle) {
+	bc.contracts.Oracle.Module.Store(mod)
+	bc.contracts.Designate.OracleService.Store(mod)
+}
+
 func (bc *Blockchain) init() error {
 	// If we could not find the version in the Store, we know that there is nothing stored.
 	ver, err := bc.dao.GetVersion()

pkg/core/blockchainer/blockchainer.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
@@ -57,6 +58,7 @@ type Blockchainer interface {
 	GetStorageItems(id int32) (map[string]*state.StorageItem, error)
 	GetTestVM(t trigger.Type, tx *transaction.Transaction, b *block.Block) *vm.VM
 	GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
+	SetOracle(service services.Oracle)
 	mempool.Feer // fee interface
 	ManagementContractHash() util.Uint160
 	PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error

pkg/core/blockchainer/services/oracle.go

@@ -0,0 +1,20 @@
+package services
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+)
+
+// Oracle specifies oracle service interface.
+type Oracle interface {
+	// AddRequests processes new requests.
+	AddRequests(map[uint64]*state.OracleRequest)
+	// RemoveRequests removes already processed requests.
+	RemoveRequests([]uint64)
+	// UpdateOracleNodes updates oracle nodes.
+	UpdateOracleNodes(keys.PublicKeys)
+	// Run runs oracle module. Must be invoked in a separate goroutine.
+	Run()
+	// Shutdown shutdowns oracle module.
+	Shutdown()
+}

pkg/core/helper_test.go

@@ -51,6 +51,12 @@ func newTestChainWithCustomCfg(t *testing.T, f func(*config.Config)) *Blockchain
 }
 
 func newTestChainWithCustomCfgAndStore(t *testing.T, st storage.Store, f func(*config.Config)) *Blockchain {
+	chain := initTestChain(t, st, f)
+	go chain.Run()
+	return chain
+}
+
+func initTestChain(t *testing.T, st storage.Store, f func(*config.Config)) *Blockchain {
 	unitTestNetCfg, err := config.Load("../../config", testchain.Network())
 	require.NoError(t, err)
 	if f != nil {
@@ -61,7 +67,6 @@ func newTestChainWithCustomCfgAndStore(t *testing.T, st storage.Store, f func(*c
 	}
 	chain, err := NewBlockchain(st, unitTestNetCfg.ProtocolConfiguration, zaptest.NewLogger(t))
 	require.NoError(t, err)
-	go chain.Run()
 	return chain
 }
 

pkg/core/native/designate.go

@@ -7,6 +7,7 @@ import (
 	"sort"
 	"sync/atomic"
 
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
@@ -32,6 +33,8 @@ type Designate struct {
 
 	// p2pSigExtensionsEnabled defines whether the P2P signature extensions logic is relevant.
 	p2pSigExtensionsEnabled bool
+
+	OracleService atomic.Value
 }
 
 type oraclesData struct {
@@ -117,6 +120,9 @@ func (s *Designate) PostPersist(ic *interop.Context) error {
 		height: height,
 	}
 	s.oracles.Store(od)
+	if orc, _ := s.OracleService.Load().(services.Oracle); orc != nil {
+		orc.UpdateOracleNodes(od.nodes.Copy())
+	}
 	s.rolesChangedFlag.Store(false)
 	return nil
 }

pkg/core/native/oracle.go

@@ -7,7 +7,9 @@ import (
 	"math"
 	"math/big"
 	"strings"
+	"sync/atomic"
 
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
@@ -36,6 +38,11 @@ type Oracle struct {
 
 	Desig        *Designate
 	oracleScript []byte
+
+	// Module is an oracle module capable of talking with the external world.
+	Module atomic.Value
+	// newRequests contains new requests created during current block.
+	newRequests map[uint64]*state.OracleRequest
 }
 
 const (
@@ -112,7 +119,11 @@ func (o *Oracle) GetOracleResponseScript() []byte {
 
 // OnPersist implements Contract interface.
 func (o *Oracle) OnPersist(ic *interop.Context) error {
-	return nil
+	var err error
+	if o.newRequests == nil {
+		o.newRequests, err = o.getRequests(ic.DAO)
+	}
+	return err
 }
 
 // PostPersist represents `postPersist` method.
@@ -120,6 +131,9 @@ func (o *Oracle) PostPersist(ic *interop.Context) error {
 	var nodes keys.PublicKeys
 	var reward []big.Int
 	single := new(big.Int).SetUint64(oracleRequestPrice)
+	var removedIDs []uint64
+
+	orc, _ := o.Module.Load().(services.Oracle)
 	for _, tx := range ic.Block.Transactions {
 		resp := getResponse(tx)
 		if resp == nil {
@@ -133,6 +147,9 @@ func (o *Oracle) PostPersist(ic *interop.Context) error {
 		if err := ic.DAO.DeleteStorageItem(o.ContractID, reqKey); err != nil {
 			return err
 		}
+		if orc != nil {
+			removedIDs = append(removedIDs, resp.ID)
+		}
 
 		idKey := makeIDListKey(req.URL)
 		idList := new(IDList)
@@ -170,7 +187,11 @@ func (o *Oracle) PostPersist(ic *interop.Context) error {
 	for i := range reward {
 		o.GAS.mint(ic, nodes[i].GetScriptHash(), &reward[i], false)
 	}
-	return nil
+
+	if len(removedIDs) != 0 && orc != nil {
+		orc.RemoveRequests(removedIDs)
+	}
+	return o.updateCache(ic.DAO)
 }
 
 // Metadata returns contract metadata.
@@ -338,6 +359,7 @@ func (o *Oracle) PutRequestInternal(id uint64, req *state.OracleRequest, d dao.D
 	if err := d.PutStorageItem(o.ContractID, reqKey, reqItem); err != nil {
 		return err
 	}
+	o.newRequests[id] = req
 
 	// Add request ID to the id list.
 	lst := new(IDList)
@@ -393,6 +415,29 @@ func (o *Oracle) getOriginalTxID(d dao.DAO, tx *transaction.Transaction) util.Ui
 	return tx.Hash()
 }
 
+// getRequests returns all requests which have not been finished yet.
+func (o *Oracle) getRequests(d dao.DAO) (map[uint64]*state.OracleRequest, error) {
+	m, err := d.GetStorageItemsWithPrefix(o.ContractID, prefixRequest)
+	if err != nil {
+		return nil, err
+	}
+	reqs := make(map[uint64]*state.OracleRequest, len(m))
+	for k, si := range m {
+		if len(k) != 8 {
+			return nil, errors.New("invalid request ID")
+		}
+		r := io.NewBinReaderFromBuf(si.Value)
+		req := new(state.OracleRequest)
+		req.DecodeBinary(r)
+		if r.Err != nil {
+			return nil, r.Err
+		}
+		id := binary.LittleEndian.Uint64([]byte(k))
+		reqs[id] = req
+	}
+	return reqs, nil
+}
+
 func makeRequestKey(id uint64) []byte {
 	k := make([]byte, 9)
 	k[0] = prefixRequest[0]
@@ -407,3 +452,22 @@ func makeIDListKey(url string) []byte {
 func (o *Oracle) getSerializableFromDAO(d dao.DAO, key []byte, item io.Serializable) error {
 	return getSerializableFromDAO(o.ContractID, d, key, item)
 }
+
+// updateCache updates cached Oracle values if they've been changed
+func (o *Oracle) updateCache(d dao.DAO) error {
+	orc, _ := o.Module.Load().(services.Oracle)
+	if orc == nil {
+		return nil
+	}
+
+	reqs := o.newRequests
+	o.newRequests = make(map[uint64]*state.OracleRequest)
+	for id := range reqs {
+		key := makeRequestKey(id)
+		if si := d.GetStorageItem(o.ContractID, key); si == nil { // tx has failed
+			delete(reqs, id)
+		}
+	}
+	orc.AddRequests(reqs)
+	return nil
+}

pkg/core/oracle_test.go

@@ -10,6 +10,7 @@ import (
 	"path"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
@@ -27,34 +28,39 @@ import (
 
 const oracleModulePath = "../services/oracle/"
 
+func getOracleConfig(t *testing.T, bc *Blockchain, w, pass string) oracle.Config {
+	return oracle.Config{
+		Log:     zaptest.NewLogger(t),
+		Network: netmode.UnitTestNet,
+		MainCfg: config.OracleConfiguration{
+			UnlockWallet: config.Wallet{
+				Path:     path.Join(oracleModulePath, w),
+				Password: pass,
+			},
+		},
+		Chain:          bc,
+		Client:         newDefaultHTTPClient(),
+		OracleScript:   bc.contracts.Oracle.NEF.Script,
+		OracleResponse: bc.contracts.Oracle.GetOracleResponseScript(),
+		OracleHash:     bc.contracts.Oracle.Hash,
+	}
+}
+
 func getTestOracle(t *testing.T, bc *Blockchain, walletPath, pass string) (
 	*wallet.Account,
 	*oracle.Oracle,
 	map[uint64]*responseWithSig,
 	chan *transaction.Transaction) {
-
 	m := make(map[uint64]*responseWithSig)
 	ch := make(chan *transaction.Transaction, 5)
-	orcCfg := oracle.Config{
+	orcCfg := getOracleConfig(t, bc, walletPath, pass)
-		Log:     zaptest.NewLogger(t),
+	orcCfg.ResponseHandler = saveToMapBroadcaster{m}
-		Network: netmode.UnitTestNet,
+	orcCfg.OnTransaction = saveTxToChan(ch)
-		Wallet: config.Wallet{
+	orcCfg.URIValidator = func(u *url.URL) error {
-			Path:     path.Join(oracleModulePath, walletPath),
+		if strings.HasPrefix(u.Host, "private") {
-			Password: pass,
+			return errors.New("private network")
-		},
+		}
-		Chain:           bc,
+		return nil
-		Client:          newDefaultHTTPClient(),
-		ResponseHandler: saveToMapBroadcaster{m},
-		OnTransaction:   saveTxToChan(ch),
-		URIValidator: func(u *url.URL) error {
-			if strings.HasPrefix(u.Host, "private") {
-				return errors.New("private network")
-			}
-			return nil
-		},
-		OracleScript:   bc.contracts.Oracle.NEF.Script,
-		OracleResponse: bc.contracts.Oracle.GetOracleResponseScript(),
-		OracleHash:     bc.contracts.Oracle.Hash,
 	}
 	orc, err := oracle.NewOracle(orcCfg)
 	require.NoError(t, err)
@@ -97,6 +103,16 @@ func TestCreateResponseTx(t *testing.T) {
 	assert.Equal(t, int64(97783360), tx.SystemFee)
 }
 
+func TestOracle_InvalidWallet(t *testing.T) {
+	bc := newTestChain(t)
+
+	_, err := oracle.NewOracle(getOracleConfig(t, bc, "./testdata/oracle1.json", "invalid"))
+	require.Error(t, err)
+
+	_, err = oracle.NewOracle(getOracleConfig(t, bc, "./testdata/oracle1.json", "one"))
+	require.NoError(t, err)
+}
+
 func TestOracle(t *testing.T) {
 	bc := newTestChain(t)
 	defer bc.Close()
@@ -128,7 +144,7 @@ func TestOracle(t *testing.T) {
 		require.NoError(t, err)
 
 		reqs := map[uint64]*state.OracleRequest{id: req}
-		orc1.AddRequests(reqs)
+		orc1.ProcessRequestsInternal(reqs)
 		require.NotNil(t, m1[id])
 		require.Equal(t, resp, m1[id].resp)
 		require.Empty(t, ch1)
@@ -151,10 +167,14 @@ func TestOracle(t *testing.T) {
 		req := checkResp(t, 1, resp)
 
 		reqs := map[uint64]*state.OracleRequest{1: req}
-		orc2.AddRequests(reqs)
+		orc2.ProcessRequestsInternal(reqs)
 		require.Equal(t, resp, m2[1].resp)
 		require.Empty(t, ch2)
 
+		t.Run("InvalidSignature", func(t *testing.T) {
+			orc1.AddResponse(acc2.PrivateKey().PublicKey(), m2[1].resp.ID, []byte{1, 2, 3})
+			require.Empty(t, ch1)
+		})
 		orc1.AddResponse(acc2.PrivateKey().PublicKey(), m2[1].resp.ID, m2[1].txSig)
 		checkEmitTx(t, ch1)
 
@@ -171,7 +191,7 @@ func TestOracle(t *testing.T) {
 			require.Empty(t, ch2)
 
 			reqs := map[uint64]*state.OracleRequest{reqID: req}
-			orc2.AddRequests(reqs)
+			orc2.ProcessRequestsInternal(reqs)
 			require.Equal(t, resp, m2[reqID].resp)
 			checkEmitTx(t, ch2)
 		})
@@ -223,6 +243,32 @@ func TestOracle(t *testing.T) {
 	})
 }
 
+func TestOracleFull(t *testing.T) {
+	bc := initTestChain(t, nil, nil)
+	acc, orc, _, _ := getTestOracle(t, bc, "./testdata/oracle2.json", "two")
+	mp := bc.GetMemPool()
+	orc.OnTransaction = func(tx *transaction.Transaction) { _ = mp.Add(tx, bc) }
+	bc.SetOracle(orc)
+
+	cs := getOracleContractState(bc.contracts.Oracle.Hash)
+	require.NoError(t, bc.contracts.Management.PutContractState(bc.dao, cs))
+
+	go bc.Run()
+	defer bc.Close()
+	go orc.Run()
+	defer orc.Shutdown()
+
+	bc.setNodesByRole(t, true, native.RoleOracle, keys.PublicKeys{acc.PrivateKey().PublicKey()})
+	putOracleRequest(t, cs.Hash, bc, "http://get.1234", new(string), "handle", []byte{}, 10_000_000)
+
+	require.Eventually(t, func() bool { return mp.Count() == 1 },
+		time.Second*2, time.Millisecond*200)
+
+	txes := mp.GetVerifiedTransactions()
+	require.Len(t, txes, 1)
+	require.True(t, txes[0].HasAttribute(transaction.OracleResponseT))
+}
+
 type saveToMapBroadcaster struct {
 	m map[uint64]*responseWithSig
 }

pkg/network/helper_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
+	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
@@ -278,7 +279,9 @@ func (chain testChain) ManagementContractHash() util.Uint160 {
 func (chain *testChain) PoolTx(tx *transaction.Transaction, _ ...*mempool.Pool) error {
 	return chain.poolTx(tx)
 }
-
+func (chain testChain) SetOracle(services.Oracle) {
+	panic("TODO")
+}
 func (chain *testChain) SubscribeForBlocks(ch chan<- *block.Block) {
 	chain.blocksCh = append(chain.blocksCh, ch)
 }

pkg/network/server.go

@@ -20,6 +20,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/network/capability"
 	"github.com/nspcc-dev/neo-go/pkg/network/payload"
+	"github.com/nspcc-dev/neo-go/pkg/services/oracle"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"go.uber.org/atomic"
 	"go.uber.org/zap"
@@ -82,6 +83,8 @@ type (
 
 		consensusStarted *atomic.Bool
 
+		oracle *oracle.Oracle
+
 		log *zap.Logger
 	}
 
@@ -142,6 +145,29 @@ func newServerFromConstructors(config ServerConfig, chain blockchainer.Blockchai
 		}
 	})
 
+	if config.OracleCfg.Enabled {
+		orcCfg := oracle.Config{
+			Log:     log,
+			Network: config.Net,
+			MainCfg: config.OracleCfg,
+			Chain:   chain,
+		}
+		orc, err := oracle.NewOracle(orcCfg)
+		if err != nil {
+			return nil, fmt.Errorf("can't initialize Oracle module: %w", err)
+		}
+		orc.SetOnTransaction(func(tx *transaction.Transaction) {
+			r := s.RelayTxn(tx)
+			if r != RelaySucceed {
+				orc.Log.Error("can't pool oracle tx",
+					zap.String("hash", tx.Hash().StringLE()),
+					zap.Uint8("reason", byte(r)))
+			}
+		})
+		s.oracle = orc
+		chain.SetOracle(orc)
+	}
+
 	srv, err := newConsensus(consensus.Config{
 		Logger:    log,
 		Broadcast: s.handleNewPayload,
@@ -203,6 +229,9 @@ func (s *Server) Start(errChan chan error) {
 	s.initStaleMemPools()
 
 	go s.broadcastTxLoop()
+	if s.oracle != nil {
+		go s.oracle.Run()
+	}
 	go s.relayBlocksLoop()
 	go s.bQueue.run()
 	go s.transport.Accept()
@@ -222,9 +251,17 @@ func (s *Server) Shutdown() {
 		p.Disconnect(errServerShutdown)
 	}
 	s.bQueue.discard()
+	if s.oracle != nil {
+		s.oracle.Shutdown()
+	}
 	close(s.quit)
 }
 
+// GetOracle returns oracle module instance.
+func (s *Server) GetOracle() *oracle.Oracle {
+	return s.oracle
+}
+
 // UnconnectedPeers returns a list of peers that are in the discovery peer list
 // but are not connected to the server.
 func (s *Server) UnconnectedPeers() []string {

pkg/network/server_config.go

@@ -66,6 +66,9 @@ type (
 
 		// TimePerBlock is an interval which should pass between two successive blocks.
 		TimePerBlock time.Duration
+
+		// OracleCfg is oracle module configuration.
+		OracleCfg config.OracleConfiguration
 	}
 )
 
@@ -96,5 +99,6 @@ func NewServerConfig(cfg config.Config) ServerConfig {
 		MinPeers:          appConfig.MinPeers,
 		Wallet:            wc,
 		TimePerBlock:      time.Duration(protoConfig.SecondsPerBlock) * time.Second,
+		OracleCfg:         appConfig.Oracle,
 	}
 }

pkg/rpc/client/rpc.go

@@ -491,6 +491,12 @@ func (c *Client) SubmitBlock(b block.Block) (util.Uint256, error) {
 	return resp.Hash, nil
 }
 
+// SubmitRawOracleResponse submits raw oracle response to the oracle node.
+// Raw params are used to avoid excessive marshalling.
+func (c *Client) SubmitRawOracleResponse(ps request.RawParams) error {
+	return c.performRequest("submitoracleresponse", ps, new(result.RelayResult))
+}
+
 // SignAndPushInvocationTx signs and pushes given script as an invocation
 // transaction  using given wif to sign it and spending the amount of gas
 // specified. It returns a hash of the invocation transaction and an error.

pkg/rpc/server/server.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	"crypto/elliptic"
 	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
@@ -23,10 +24,13 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/network"
+	"github.com/nspcc-dev/neo-go/pkg/services/oracle"
+	"github.com/nspcc-dev/neo-go/pkg/services/oracle/broadcaster"
 	"github.com/nspcc-dev/neo-go/pkg/rpc"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/request"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/response"
@@ -47,6 +51,7 @@ type (
 		network          netmode.Magic
 		stateRootEnabled bool
 		coreServer       *network.Server
+		oracle           *oracle.Oracle
 		log              *zap.Logger
 		https            *http.Server
 		shutdown         chan struct{}
@@ -116,6 +121,7 @@ var rpcHandlers = map[string]func(*Server, request.Params) (interface{}, *respon
 	"invokecontractverify":   (*Server).invokeContractVerify,
 	"sendrawtransaction":     (*Server).sendrawtransaction,
 	"submitblock":            (*Server).submitBlock,
+	"submitoracleresponse":   (*Server).submitOracleResponse,
 	"validateaddress":        (*Server).validateAddress,
 	"verifyproof":            (*Server).verifyProof,
 }
@@ -134,7 +140,8 @@ var invalidBlockHeightError = func(index int, height int) *response.Error {
 var upgrader = websocket.Upgrader{}
 
 // New creates a new Server struct.
-func New(chain blockchainer.Blockchainer, conf rpc.Config, coreServer *network.Server, log *zap.Logger) Server {
+func New(chain blockchainer.Blockchainer, conf rpc.Config, coreServer *network.Server,
+	orc *oracle.Oracle, log *zap.Logger) Server {
 	httpServer := &http.Server{
 		Addr: conf.Address + ":" + strconv.FormatUint(uint64(conf.Port), 10),
 	}
@@ -146,6 +153,9 @@ func New(chain blockchainer.Blockchainer, conf rpc.Config, coreServer *network.S
 		}
 	}
 
+	if orc != nil {
+		orc.SetBroadcaster(broadcaster.New(orc.MainCfg, log))
+	}
 	return Server{
 		Server:           httpServer,
 		chain:            chain,
@@ -154,6 +164,7 @@ func New(chain blockchainer.Blockchainer, conf rpc.Config, coreServer *network.S
 		stateRootEnabled: chain.GetConfig().StateRootInHeader,
 		coreServer:       coreServer,
 		log:              log,
+		oracle:           orc,
 		https:            tlsServer,
 		shutdown:         make(chan struct{}),
 
@@ -1223,6 +1234,38 @@ func (s *Server) submitBlock(reqParams request.Params) (interface{}, *response.E
 	}, nil
 }
 
+func (s *Server) submitOracleResponse(ps request.Params) (interface{}, *response.Error) {
+	if s.oracle == nil {
+		return nil, response.NewInternalServerError("oracle is not enabled", nil)
+	}
+	var pub *keys.PublicKey
+	pubBytes, err := ps.Value(0).GetBytesBase64()
+	if err == nil {
+		pub, err = keys.NewPublicKeyFromBytes(pubBytes, elliptic.P256())
+	}
+	if err != nil {
+		return nil, response.NewInvalidParamsError("public key is missing", err)
+	}
+	reqID, err := ps.Value(1).GetInt()
+	if err != nil {
+		return nil, response.NewInvalidParamsError("request ID is missing", err)
+	}
+	txSig, err := ps.Value(2).GetBytesBase64()
+	if err != nil {
+		return nil, response.NewInvalidParamsError("tx signature is missing", err)
+	}
+	msgSig, err := ps.Value(3).GetBytesBase64()
+	if err != nil {
+		return nil, response.NewInvalidParamsError("msg signature is missing", err)
+	}
+	data := broadcaster.GetMessage(pubBytes, uint64(reqID), txSig)
+	if !pub.Verify(msgSig, hash.Sha256(data).BytesBE()) {
+		return nil, response.NewRPCError("Invalid sign", "", nil)
+	}
+	s.oracle.AddResponse(pub, uint64(reqID), txSig)
+	return json.RawMessage([]byte("{}")), nil
+}
+
 func (s *Server) sendrawtransaction(reqParams request.Params) (interface{}, *response.Error) {
 	var resultsErr *response.Error
 	var results interface{}

pkg/rpc/server/server_helper_test.go

@@ -16,13 +16,14 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/network"
+	"github.com/nspcc-dev/neo-go/pkg/services/oracle"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zaptest"
 )
 
-func getUnitTestChain(t *testing.T) (*core.Blockchain, config.Config, *zap.Logger) {
+func getUnitTestChain(t *testing.T, enableOracle bool) (*core.Blockchain, *oracle.Oracle, config.Config, *zap.Logger) {
 	net := netmode.UnitTestNet
 	configPath := "../../../config"
 	cfg, err := config.Load(configPath, net)
@@ -33,9 +34,26 @@ func getUnitTestChain(t *testing.T) (*core.Blockchain, config.Config, *zap.Logge
 	chain, err := core.NewBlockchain(memoryStore, cfg.ProtocolConfiguration, logger)
 	require.NoError(t, err, "could not create chain")
 
+	var orc *oracle.Oracle
+	if enableOracle {
+		cfg.ApplicationConfiguration.Oracle.Enabled = true
+		cfg.ApplicationConfiguration.Oracle.UnlockWallet = config.Wallet{
+			Path:     "../../services/oracle/testdata/oracle1.json",
+			Password: "one",
+		}
+		orc, err = oracle.NewOracle(oracle.Config{
+			Log:     logger,
+			Network: netmode.UnitTestNet,
+			MainCfg: cfg.ApplicationConfiguration.Oracle,
+			Chain:   chain,
+		})
+		require.NoError(t, err)
+		chain.SetOracle(orc)
+	}
+
 	go chain.Run()
 
-	return chain, cfg, logger
+	return chain, orc, cfg, logger
 }
 
 func getTestBlocks(t *testing.T) []*block.Block {
@@ -61,13 +79,13 @@ func getTestBlocks(t *testing.T) []*block.Block {
 	return blocks
 }
 
-func initClearServerWithInMemoryChain(t *testing.T) (*core.Blockchain, *Server, *httptest.Server) {
+func initClearServerWithOracle(t *testing.T, needOracle bool) (*core.Blockchain, *Server, *httptest.Server) {
-	chain, cfg, logger := getUnitTestChain(t)
+	chain, orc, cfg, logger := getUnitTestChain(t, needOracle)
 
 	serverConfig := network.NewServerConfig(cfg)
 	server, err := network.NewServer(serverConfig, chain, logger)
 	require.NoError(t, err)
-	rpcServer := New(chain, cfg.ApplicationConfiguration.RPC, server, logger)
+	rpcServer := New(chain, cfg.ApplicationConfiguration.RPC, server, orc, logger)
 	errCh := make(chan error, 2)
 	rpcServer.Start(errCh)
 
@@ -77,6 +95,10 @@ func initClearServerWithInMemoryChain(t *testing.T) (*core.Blockchain, *Server,
 	return chain, &rpcServer, srv
 }
 
+func initClearServerWithInMemoryChain(t *testing.T) (*core.Blockchain, *Server, *httptest.Server) {
+	return initClearServerWithOracle(t, false)
+}
+
 func initServerWithInMemoryChain(t *testing.T) (*core.Blockchain, *Server, *httptest.Server) {
 	chain, rpcServer, srv := initClearServerWithInMemoryChain(t)
 

pkg/rpc/server/server_test.go

@@ -25,8 +25,10 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/io"
+	rpc2 "github.com/nspcc-dev/neo-go/pkg/services/oracle/broadcaster"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/response"
 	"github.com/nspcc-dev/neo-go/pkg/rpc/response/result"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
@@ -885,6 +887,13 @@ var rpcTestCases = map[string][]rpcTestCase{
 			fail:   true,
 		},
 	},
+	"submitoracleresponse": {
+		{
+			name:   "no params",
+			params: `[]`,
+			fail:   true,
+		},
+	},
 	"validateaddress": {
 		{
 			name:   "positive",
@@ -920,6 +929,39 @@ func TestRPC(t *testing.T) {
 	})
 }
 
+func TestSubmitOracle(t *testing.T) {
+	chain, rpcSrv, httpSrv := initClearServerWithOracle(t, true)
+	defer chain.Close()
+	defer rpcSrv.Shutdown()
+
+	rpc := `{"jsonrpc": "2.0", "id": 1, "method": "submitoracleresponse", "params": %s}`
+	runCase := func(t *testing.T, fail bool, params ...string) func(t *testing.T) {
+		return func(t *testing.T) {
+			ps := `[` + strings.Join(params, ",") + `]`
+			req := fmt.Sprintf(rpc, ps)
+			body := doRPCCallOverHTTP(req, httpSrv.URL, t)
+			checkErrGetResult(t, body, fail)
+		}
+	}
+	t.Run("MissingKey", runCase(t, true))
+	t.Run("InvalidKey", runCase(t, true, `"1234"`))
+
+	priv, err := keys.NewPrivateKey()
+	require.NoError(t, err)
+	pubStr := `"` + base64.StdEncoding.EncodeToString(priv.PublicKey().Bytes()) + `"`
+	t.Run("InvalidReqID", runCase(t, true, pubStr, `"notanumber"`))
+	t.Run("InvalidTxSignature", runCase(t, true, pubStr, `1`, `"qwerty"`))
+
+	txSig := priv.Sign([]byte{1, 2, 3})
+	txSigStr := `"` + base64.StdEncoding.EncodeToString(txSig) + `"`
+	t.Run("MissingMsgSignature", runCase(t, true, pubStr, `1`, txSigStr))
+	t.Run("InvalidMsgSignature", runCase(t, true, pubStr, `1`, txSigStr, `"0123"`))
+
+	msg := rpc2.GetMessage(priv.PublicKey().Bytes(), 1, txSig)
+	msgSigStr := `"` + base64.StdEncoding.EncodeToString(priv.Sign(msg)) + `"`
+	t.Run("Valid", runCase(t, false, pubStr, `1`, txSigStr, msgSigStr))
+}
+
 // testRPCProtocol runs a full set of tests using given callback to make actual
 // calls. Some tests change the chain state, thus we reinitialize the chain from
 // scratch here.

pkg/services/oracle/broadcaster/oracle.go

@@ -0,0 +1,85 @@
+package broadcaster
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/binary"
+	"time"
+
+	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/nspcc-dev/neo-go/pkg/rpc/client"
+	"github.com/nspcc-dev/neo-go/pkg/rpc/request"
+	"github.com/nspcc-dev/neo-go/pkg/services/oracle"
+	"go.uber.org/zap"
+)
+
+type rpcBroascaster struct {
+	clients map[string]*client.Client
+	log     *zap.Logger
+
+	sendTimeout time.Duration
+}
+
+const (
+	defaultSendTimeout = time.Second * 4
+)
+
+// New returns new struct capable of broadcasting oracle responses.
+func New(cfg config.OracleConfiguration, log *zap.Logger) oracle.Broadcaster {
+	if cfg.ResponseTimeout == 0 {
+		cfg.ResponseTimeout = defaultSendTimeout
+	}
+	r := &rpcBroascaster{
+		clients:     make(map[string]*client.Client, len(cfg.Nodes)),
+		log:         log,
+		sendTimeout: cfg.ResponseTimeout,
+	}
+	for i := range cfg.Nodes {
+		// We ignore error as not every node can be available on startup.
+		r.clients[cfg.Nodes[i]], _ = client.New(context.Background(), "http://"+cfg.Nodes[i], client.Options{
+			DialTimeout:    cfg.ResponseTimeout,
+			RequestTimeout: cfg.ResponseTimeout,
+		})
+	}
+	return r
+}
+
+// SendResponse implements interfaces.Broadcaster.
+func (r *rpcBroascaster) SendResponse(priv *keys.PrivateKey, resp *transaction.OracleResponse, txSig []byte) {
+	pub := priv.PublicKey()
+	data := GetMessage(pub.Bytes(), resp.ID, txSig)
+	msgSig := priv.Sign(data)
+	params := request.NewRawParams(
+		base64.StdEncoding.EncodeToString(pub.Bytes()),
+		resp.ID,
+		base64.StdEncoding.EncodeToString(txSig),
+		base64.StdEncoding.EncodeToString(msgSig),
+	)
+	for addr, c := range r.clients {
+		if c == nil {
+			var err error
+			c, err = client.New(context.Background(), addr, client.Options{
+				DialTimeout:    r.sendTimeout,
+				RequestTimeout: r.sendTimeout,
+			})
+			if err != nil {
+				r.log.Debug("can't connect to oracle node", zap.String("address", addr), zap.Error(err))
+				continue
+			}
+			r.clients[addr] = c
+		}
+		err := c.SubmitRawOracleResponse(params)
+		r.log.Debug("error during oracle response submit", zap.String("address", addr), zap.Error(err))
+	}
+}
+
+// GetMessage returns data which is signed upon sending response by RPC.
+func GetMessage(pubBytes []byte, reqID uint64, txSig []byte) []byte {
+	data := make([]byte, len(pubBytes)+8+len(txSig))
+	copy(data, pubBytes)
+	binary.LittleEndian.PutUint64(data[len(pubBytes):], uint64(reqID))
+	copy(data[len(pubBytes)+8:], txSig)
+	return data
+}

pkg/services/oracle/nodes.go

@@ -33,7 +33,7 @@ func (o *Oracle) UpdateOracleNodes(oracleNodes keys.PublicKeys) {
 			if acc.PrivateKey() != nil {
 				break
 			}
-			err := acc.Decrypt(o.Wallet.Password)
+			err := acc.Decrypt(o.MainCfg.UnlockWallet.Password)
 			if err != nil {
 				o.Log.Error("can't unlock account",
 					zap.String("address", address.Uint160ToString(acc.Contract.ScriptHash())),

pkg/services/oracle/oracle.go

@@ -1,6 +1,7 @@
 package oracle
 
 import (
+	"errors"
 	"net/http"
 	"net/url"
 	"sync"
@@ -9,6 +10,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -31,6 +33,9 @@ type (
 		oracleNodes        keys.PublicKeys
 		oracleSignContract []byte
 
+		close      chan struct{}
+		requestMap chan map[uint64]*state.OracleRequest
+
 		// respMtx protects responses map.
 		respMtx   sync.RWMutex
 		responses map[uint64]*incompleteTx
@@ -42,7 +47,7 @@ type (
 	Config struct {
 		Log             *zap.Logger
 		Network         netmode.Magic
-		Wallet          config.Wallet
+		MainCfg         config.OracleConfiguration
 		Client          HTTPClient
 		Chain           blockchainer.Blockchainer
 		ResponseHandler Broadcaster
@@ -81,19 +86,35 @@ func NewOracle(cfg Config) (*Oracle, error) {
 	o := &Oracle{
 		Config: cfg,
 
-		responses: make(map[uint64]*incompleteTx),
+		close:      make(chan struct{}),
+		requestMap: make(chan map[uint64]*state.OracleRequest, 1),
+		responses:  make(map[uint64]*incompleteTx),
+	}
+	if o.MainCfg.RequestTimeout == 0 {
+		o.MainCfg.RequestTimeout = defaultRequestTimeout
 	}
 
 	var err error
-	w := cfg.Wallet
+	w := cfg.MainCfg.UnlockWallet
 	if o.wallet, err = wallet.NewWalletFromFile(w.Path); err != nil {
 		return nil, err
 	}
 
+	haveAccount := false
+	for _, acc := range o.wallet.Accounts {
+		if err := acc.Decrypt(w.Password); err == nil {
+			haveAccount = true
+			break
+		}
+	}
+	if !haveAccount {
+		return nil, errors.New("no wallet account could be unlocked")
+	}
+
 	if o.Client == nil {
 		var client http.Client
 		client.Transport = &http.Transport{DisableKeepAlives: true}
-		client.Timeout = defaultRequestTimeout
+		client.Timeout = o.MainCfg.RequestTimeout
 		o.Client = &client
 	}
 	if o.ResponseHandler == nil {
@@ -108,6 +129,36 @@ func NewOracle(cfg Config) (*Oracle, error) {
 	return o, nil
 }
 
+// Shutdown shutdowns Oracle.
+func (o *Oracle) Shutdown() {
+	close(o.close)
+}
+
+// Run runs must be executed in a separate goroutine.
+func (o *Oracle) Run() {
+	for {
+		select {
+		case <-o.close:
+			return
+		case reqs := <-o.requestMap:
+			o.ProcessRequestsInternal(reqs)
+		}
+	}
+}
+
+func (o *Oracle) getOnTransaction() TxCallback {
+	o.mtx.RLock()
+	defer o.mtx.RUnlock()
+	return o.OnTransaction
+}
+
+// SetOnTransaction sets callback to pool and broadcast tx.
+func (o *Oracle) SetOnTransaction(cb TxCallback) {
+	o.mtx.Lock()
+	defer o.mtx.Unlock()
+	o.OnTransaction = cb
+}
+
 func (o *Oracle) getBroadcaster() Broadcaster {
 	o.mtx.RLock()
 	defer o.mtx.RUnlock()

pkg/services/oracle/request.go

@@ -24,6 +24,26 @@ func (o *Oracle) RemoveRequests(ids []uint64) {
 
 // AddRequests saves all requests in-fly for further processing.
 func (o *Oracle) AddRequests(reqs map[uint64]*state.OracleRequest) {
+	if len(reqs) == 0 {
+		return
+	}
+
+	select {
+	case o.requestMap <- reqs:
+	default:
+		select {
+		case old := <-o.requestMap:
+			for id, r := range old {
+				reqs[id] = r
+			}
+		default:
+		}
+		o.requestMap <- reqs
+	}
+}
+
+// ProcessRequestsInternal processes provided requests synchronously.
+func (o *Oracle) ProcessRequestsInternal(reqs map[uint64]*state.OracleRequest) {
 	acc := o.getAccount()
 	if acc == nil {
 		return
@@ -40,7 +60,7 @@ func (o *Oracle) AddRequests(reqs map[uint64]*state.OracleRequest) {
 func (o *Oracle) processRequest(priv *keys.PrivateKey, id uint64, req *state.OracleRequest) error {
 	resp := &transaction.OracleResponse{ID: id}
 	u, err := url.ParseRequestURI(req.URL)
-	if err == nil {
+	if err == nil && !o.MainCfg.AllowPrivateHost {
 		err = o.URIValidator(u)
 	}
 	if err != nil {
@@ -107,11 +127,15 @@ func (o *Oracle) processRequest(priv *keys.PrivateKey, id uint64, req *state.Ora
 	incTx.addResponse(priv.PublicKey(), backupSig, true)
 
 	readyTx, ready := incTx.finalize(o.getOracleNodes())
+	if ready {
+		ready = !incTx.isSent
+		incTx.isSent = true
+	}
 	incTx.Unlock()
 
 	o.getBroadcaster().SendResponse(priv, resp, txSig)
 	if ready {
-		o.OnTransaction(readyTx)
+		o.getOnTransaction()(readyTx)
 	}
 	return nil
 }

pkg/services/oracle/response.go

@@ -50,10 +50,14 @@ func (o *Oracle) AddResponse(pub *keys.PublicKey, reqID uint64, txSig []byte) {
 	}
 	incTx.addResponse(pub, txSig, isBackup)
 	readyTx, ready := incTx.finalize(o.getOracleNodes())
+	if ready {
+		ready = !incTx.isSent
+		incTx.isSent = true
+	}
 	incTx.Unlock()
 
 	if ready {
-		o.OnTransaction(readyTx)
+		o.getOnTransaction()(readyTx)
 	}
 }
 

pkg/services/oracle/transaction.go

@@ -13,6 +13,8 @@ import (
 type (
 	incompleteTx struct {
 		sync.RWMutex
+		// isSent is true tx was already broadcasted.
+		isSent bool
 		// tx is oracle response transaction.
 		tx *transaction.Transaction
 		// sigs contains signature from every oracle node.