[rpc] Add Rate Limiter and cache for RPCs (#3711)

* Fix 1.0.4 migration func for rate limiter

cmd/harmony/config.go

@@ -131,7 +131,9 @@ type wsConfig struct {
 }
 
 type rpcOptConfig struct {
-	DebugEnabled bool // Enables PrivateDebugService APIs, including the EVM tracer
+	DebugEnabled      bool // Enables PrivateDebugService APIs, including the EVM tracer
+	RateLimterEnabled bool // Enable Rate limiter for RPC
+	RequestsPerSecond int  // for RPC rate limiter
 }
 
 type devnetConfig struct {

cmd/harmony/config_migrations.go

@@ -90,6 +90,14 @@ func init() {
 			confTree.Set("HTTP.RosettaPort", defaultConfig.HTTP.RosettaPort)
 		}
 
+		if confTree.Get("RPCOpt.RateLimterEnabled") == nil {
+			confTree.Set("RPCOpt.RateLimterEnabled", defaultConfig.RPCOpt.RateLimterEnabled)
+		}
+
+		if confTree.Get("RPCOpt.RequestsPerSecond") == nil {
+			confTree.Set("RPCOpt.RequestsPerSecond", defaultConfig.RPCOpt.RequestsPerSecond)
+		}
+
 		if confTree.Get("P2P.IP") == nil {
 			confTree.Set("P2P.IP", defaultConfig.P2P.IP)
 		}

cmd/harmony/config_migrations_test.go

@@ -135,7 +135,6 @@ Version = "1.0.3"
   Enabled = true
   IP = "127.0.0.1"
   Port = 9800
-
 `)
 
 	V1_0_4ConfigDefault = []byte(`

cmd/harmony/default.go

@@ -38,7 +38,9 @@ var defaultConfig = harmonyConfig{
 		Port:    nodeconfig.DefaultWSPort,
 	},
 	RPCOpt: rpcOptConfig{
-		DebugEnabled: false,
+		DebugEnabled:      false,
+		RateLimterEnabled: true,
+		RequestsPerSecond: nodeconfig.DefaultRPCRateLimit,
 	},
 	BLSKeys: blsConfig{
 		KeyDir:   "./.hmy/blskeys",

cmd/harmony/flags.go

@@ -74,6 +74,8 @@ var (
 
 	rpcOptFlags = []cli.Flag{
 		rpcDebugEnabledFlag,
+		rpcRateLimiterEnabledFlag,
+		rpcRateLimitFlag,
 	}
 
 	blsFlags = append(newBLSFlags, legacyBLSFlags...)
@@ -628,12 +630,31 @@ var (
 		DefValue: defaultConfig.RPCOpt.DebugEnabled,
 		Hidden:   true,
 	}
+
+	rpcRateLimiterEnabledFlag = cli.BoolFlag{
+		Name:     "rpc.ratelimiter",
+		Usage:    "enable rate limiter for RPCs",
+		DefValue: defaultConfig.RPCOpt.RateLimterEnabled,
+	}
+
+	rpcRateLimitFlag = cli.IntFlag{
+		Name:     "rpc.ratelimit",
+		Usage:    "the number of requests per second for RPCs",
+		DefValue: defaultConfig.RPCOpt.RequestsPerSecond,
+	}
 )
 
 func applyRPCOptFlags(cmd *cobra.Command, config *harmonyConfig) {
 	if cli.IsFlagChanged(cmd, rpcDebugEnabledFlag) {
 		config.RPCOpt.DebugEnabled = cli.GetBoolFlagValue(cmd, rpcDebugEnabledFlag)
 	}
+	if cli.IsFlagChanged(cmd, rpcRateLimiterEnabledFlag) {
+		config.RPCOpt.RateLimterEnabled = cli.GetBoolFlagValue(cmd, rpcRateLimiterEnabledFlag)
+	}
+	if cli.IsFlagChanged(cmd, rpcRateLimitFlag) {
+		config.RPCOpt.RequestsPerSecond = cli.GetIntFlagValue(cmd, rpcRateLimitFlag)
+	}
+
 }
 
 // bls flags

cmd/harmony/flags_test.go

@@ -66,6 +66,11 @@ func TestHarmonyFlags(t *testing.T) {
 					RosettaEnabled: false,
 					RosettaPort:    9700,
 				},
+				RPCOpt: rpcOptConfig{
+					DebugEnabled:      false,
+					RateLimterEnabled: true,
+					RequestsPerSecond: 300,
+				},
 				WS: wsConfig{
 					Enabled: true,
 					IP:      "127.0.0.1",
@@ -535,7 +540,36 @@ func TestRPCOptFlags(t *testing.T) {
 		{
 			args: []string{"--rpc.debug"},
 			expConfig: rpcOptConfig{
-				DebugEnabled: true,
+				DebugEnabled:      true,
+				RateLimterEnabled: true,
+				RequestsPerSecond: 300,
+			},
+		},
+
+		{
+			args: []string{},
+			expConfig: rpcOptConfig{
+				DebugEnabled:      false,
+				RateLimterEnabled: true,
+				RequestsPerSecond: 300,
+			},
+		},
+
+		{
+			args: []string{"--rpc.ratelimiter", "--rpc.ratelimit", "1000"},
+			expConfig: rpcOptConfig{
+				DebugEnabled:      false,
+				RateLimterEnabled: true,
+				RequestsPerSecond: 1000,
+			},
+		},
+
+		{
+			args: []string{"--rpc.ratelimiter=false", "--rpc.ratelimit", "1000"},
+			expConfig: rpcOptConfig{
+				DebugEnabled:      false,
+				RateLimterEnabled: false,
+				RequestsPerSecond: 1000,
 			},
 		},
 	}

cmd/harmony/main.go

@@ -321,13 +321,15 @@ func setupNodeAndRun(hc harmonyConfig) {
 
 	// Parse RPC config
 	nodeConfig.RPCServer = nodeconfig.RPCServerConfig{
-		HTTPEnabled:  hc.HTTP.Enabled,
+		HTTPEnabled:        hc.HTTP.Enabled,
-		HTTPIp:       hc.HTTP.IP,
+		HTTPIp:             hc.HTTP.IP,
-		HTTPPort:     hc.HTTP.Port,
+		HTTPPort:           hc.HTTP.Port,
-		WSEnabled:    hc.WS.Enabled,
+		WSEnabled:          hc.WS.Enabled,
-		WSIp:         hc.WS.IP,
+		WSIp:               hc.WS.IP,
-		WSPort:       hc.WS.Port,
+		WSPort:             hc.WS.Port,
-		DebugEnabled: hc.RPCOpt.DebugEnabled,
+		DebugEnabled:       hc.RPCOpt.DebugEnabled,
+		RateLimiterEnabled: hc.RPCOpt.RateLimterEnabled,
+		RequestsPerSecond:  hc.RPCOpt.RequestsPerSecond,
 	}
 
 	// Parse rosetta config

go.mod

@@ -56,6 +56,7 @@ require (
 	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
+	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba
 	golang.org/x/tools v0.0.0-20210106214847-113979e3529a
 	google.golang.org/grpc v1.33.2
 	google.golang.org/protobuf v1.25.0

internal/configs/node/config.go

@@ -107,6 +107,9 @@ type RPCServerConfig struct {
 	WSPort    int
 
 	DebugEnabled bool
+
+	RateLimiterEnabled bool
+	RequestsPerSecond  int
 }
 
 // RosettaServerConfig is the config for the rosetta server

internal/configs/node/network.go

@@ -56,6 +56,11 @@ const (
 	DefaultPrometheusPort = 9900
 )
 
+const (
+	// DefaultRateLimit for RPC, the number of requests per second
+	DefaultRPCRateLimit = 300
+)
+
 const (
 	// rpcHTTPPortOffset is the port offset for RPC HTTP requests
 	rpcHTTPPortOffset = 500

rpc/blockchain.go

@@ -4,10 +4,12 @@ import (
 	"context"
 	"fmt"
 	"math/big"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/rpc"
+	"golang.org/x/time/rate"
 
 	"github.com/harmony-one/harmony/hmy"
 	"github.com/harmony-one/harmony/internal/chain"
@@ -21,23 +23,43 @@ import (
 	v2 "github.com/harmony-one/harmony/rpc/v2"
 	"github.com/harmony-one/harmony/shard"
 	stakingReward "github.com/harmony-one/harmony/staking/reward"
+
+	lru "github.com/hashicorp/golang-lru"
 )
 
 // PublicBlockchainService provides an API to access the Harmony blockchain.
 // It offers only methods that operate on public data that is freely available to anyone.
 type PublicBlockchainService struct {
-	hmy     *hmy.Harmony
+	hmy        *hmy.Harmony
-	version Version
+	version    Version
+	limiter    *rate.Limiter
+	blockCache *lru.Cache
 }
 
+const (
+	DefaultRateLimiterWaitTimeout = 5 * time.Second
+	blockCacheLimit               = 256
+)
+
 // NewPublicBlockchainAPI creates a new API for the RPC interface
-func NewPublicBlockchainAPI(hmy *hmy.Harmony, version Version) rpc.API {
+func NewPublicBlockchainAPI(hmy *hmy.Harmony, version Version, limiterEnable bool, limit int) rpc.API {
-	return rpc.API{
+	blockCache, _ := lru.New(blockCacheLimit)
-		Namespace: version.Namespace(),
+	if limiterEnable {
-		Version:   APIVersion,
+		return rpc.API{
-		Service:   &PublicBlockchainService{hmy, version},
+			Namespace: version.Namespace(),
-		Public:    true,
+			Version:   APIVersion,
+			Service:   &PublicBlockchainService{hmy, version, rate.NewLimiter(rate.Limit(limit), 1), blockCache},
+			Public:    true,
+		}
+	} else {
+		return rpc.API{
+			Namespace: version.Namespace(),
+			Version:   APIVersion,
+			Service:   &PublicBlockchainService{hmy, version, nil, blockCache},
+			Public:    true,
+		}
 	}
+
 }
 
 // ChainId returns the chain id of the chain - required by MetaMask
@@ -122,14 +144,33 @@ func (s *PublicBlockchainService) BlockNumber(ctx context.Context) (interface{},
 	}
 }
 
+func (s *PublicBlockchainService) wait(ctx context.Context) error {
+	if s.limiter != nil {
+		deadlineCtx, cancel := context.WithTimeout(ctx, DefaultRateLimiterWaitTimeout)
+		defer cancel()
+		return s.limiter.Wait(deadlineCtx)
+	}
+	return nil
+}
+
 // GetBlockByNumber returns the requested block. When blockNum is -1 the chain head is returned. When fullTx is true all
 // transactions in the block are returned in full detail, otherwise only the transaction hash is returned.
 // When withSigners in BlocksArgs is true it shows block signers for this block in list of one addresses.
 func (s *PublicBlockchainService) GetBlockByNumber(
 	ctx context.Context, blockNumber BlockNumber, opts interface{},
 ) (response StructuredResponse, err error) {
-	// Process arguments based on version
+
 	blockNum := blockNumber.EthBlockNumber()
+	if block, ok := s.blockCache.Get(uint64(blockNum)); ok {
+		return block.(StructuredResponse), nil
+	}
+
+	err = s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	// Process arguments based on version
 	var blockArgs *rpc_common.BlockArgs
 	blockArgs, ok := opts.(*rpc_common.BlockArgs)
 	if !ok {
@@ -186,6 +227,7 @@ func (s *PublicBlockchainService) GetBlockByNumber(
 			}
 		}
 
+		s.blockCache.Add(uint64(blockNum), response)
 		return response, err
 	}
 
@@ -198,6 +240,12 @@ func (s *PublicBlockchainService) GetBlockByNumber(
 func (s *PublicBlockchainService) GetBlockByHash(
 	ctx context.Context, blockHash common.Hash, opts interface{},
 ) (response StructuredResponse, err error) {
+
+	err = s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Process arguments based on version
 	var blockArgs *rpc_common.BlockArgs
 	blockArgs, ok := opts.(*rpc_common.BlockArgs)
@@ -260,6 +308,12 @@ func (s *PublicBlockchainService) GetBlocks(
 	ctx context.Context, blockNumberStart BlockNumber,
 	blockNumberEnd BlockNumber, blockArgs *rpc_common.BlockArgs,
 ) ([]StructuredResponse, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	blockStart := blockNumberStart.Int64()
 	blockEnd := blockNumberEnd.Int64()
 
@@ -469,6 +523,11 @@ func (s *PublicBlockchainService) GetLeader(ctx context.Context) (string, error)
 func (s *PublicBlockchainService) GetShardingStructure(
 	ctx context.Context,
 ) ([]StructuredResponse, error) {
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Get header and number of shards.
 	epoch := s.hmy.CurrentBlock().Epoch()
 	numShard := shard.Schedule.InstanceForEpoch(epoch).NumShards()
@@ -487,6 +546,12 @@ func (s *PublicBlockchainService) GetShardID(ctx context.Context) (int, error) {
 func (s *PublicBlockchainService) GetBalanceByBlockNumber(
 	ctx context.Context, address string, blockNumber BlockNumber,
 ) (interface{}, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Process number based on version
 	blockNum := blockNumber.EthBlockNumber()
 
@@ -512,6 +577,12 @@ func (s *PublicBlockchainService) GetBalanceByBlockNumber(
 
 // LatestHeader returns the latest header information
 func (s *PublicBlockchainService) LatestHeader(ctx context.Context) (StructuredResponse, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Fetch Header
 	header, err := s.hmy.HeaderByNumber(ctx, rpc.LatestBlockNumber)
 	if err != nil {
@@ -535,6 +606,12 @@ func (s *PublicBlockchainService) GetLatestChainHeaders(
 func (s *PublicBlockchainService) GetLastCrossLinks(
 	ctx context.Context,
 ) ([]StructuredResponse, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	if !isBeaconShard(s.hmy) {
 		return nil, ErrNotBeaconShard
 	}
@@ -561,6 +638,11 @@ func (s *PublicBlockchainService) GetLastCrossLinks(
 func (s *PublicBlockchainService) GetHeaderByNumber(
 	ctx context.Context, blockNumber BlockNumber,
 ) (StructuredResponse, error) {
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Process number based on version
 	blockNum := blockNumber.EthBlockNumber()
 
@@ -583,6 +665,11 @@ func (s *PublicBlockchainService) GetHeaderByNumber(
 func (s *PublicBlockchainService) GetCurrentUtilityMetrics(
 	ctx context.Context,
 ) (StructuredResponse, error) {
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	if !isBeaconShard(s.hmy) {
 		return nil, ErrNotBeaconShard
 	}
@@ -601,6 +688,11 @@ func (s *PublicBlockchainService) GetCurrentUtilityMetrics(
 func (s *PublicBlockchainService) GetSuperCommittees(
 	ctx context.Context,
 ) (StructuredResponse, error) {
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	if !isBeaconShard(s.hmy) {
 		return nil, ErrNotBeaconShard
 	}
@@ -619,6 +711,12 @@ func (s *PublicBlockchainService) GetSuperCommittees(
 func (s *PublicBlockchainService) GetCurrentBadBlocks(
 	ctx context.Context,
 ) ([]StructuredResponse, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	// Fetch bad blocks and format
 	badBlocks := []StructuredResponse{}
 	for _, blk := range s.hmy.GetCurrentBadBlocks() {
@@ -651,6 +749,12 @@ func (s *PublicBlockchainService) GetCirculatingSupply(
 func (s *PublicBlockchainService) GetStakingNetworkInfo(
 	ctx context.Context,
 ) (StructuredResponse, error) {
+
+	err := s.wait(ctx)
+	if err != nil {
+		return nil, err
+	}
+
 	if !isBeaconShard(s.hmy) {
 		return nil, ErrNotBeaconShard
 	}

rpc/rpc.go

@@ -70,7 +70,7 @@ func (n Version) Namespace() string {
 
 // StartServers starts the http & ws servers
 func StartServers(hmy *hmy.Harmony, apis []rpc.API, config nodeconfig.RPCServerConfig) error {
-	apis = append(apis, getAPIs(hmy, config.DebugEnabled)...)
+	apis = append(apis, getAPIs(hmy, config.DebugEnabled, config.RateLimiterEnabled, config.RequestsPerSecond)...)
 
 	if config.HTTPEnabled {
 		httpEndpoint = fmt.Sprintf("%v:%v", config.HTTPIp, config.HTTPPort)
@@ -121,15 +121,15 @@ func StopServers() error {
 }
 
 // getAPIs returns all the API methods for the RPC interface
-func getAPIs(hmy *hmy.Harmony, debugEnable bool) []rpc.API {
+func getAPIs(hmy *hmy.Harmony, debugEnable bool, rateLimiterEnable bool, ratelimit int) []rpc.API {
 	publicAPIs := []rpc.API{
 		// Public methods
 		NewPublicHarmonyAPI(hmy, V1),
 		NewPublicHarmonyAPI(hmy, V2),
 		NewPublicHarmonyAPI(hmy, Eth),
-		NewPublicBlockchainAPI(hmy, V1),
+		NewPublicBlockchainAPI(hmy, V1, rateLimiterEnable, ratelimit),
-		NewPublicBlockchainAPI(hmy, V2),
+		NewPublicBlockchainAPI(hmy, V2, rateLimiterEnable, ratelimit),
-		NewPublicBlockchainAPI(hmy, Eth),
+		NewPublicBlockchainAPI(hmy, Eth, rateLimiterEnable, ratelimit),
 		NewPublicContractAPI(hmy, V1),
 		NewPublicContractAPI(hmy, V2),
 		NewPublicContractAPI(hmy, Eth),