[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,
-		HTTPIp:       hc.HTTP.IP,
-		HTTPPort:     hc.HTTP.Port,
-		WSEnabled:    hc.WS.Enabled,
-		WSIp:         hc.WS.IP,
-		WSPort:       hc.WS.Port,
-		DebugEnabled: hc.RPCOpt.DebugEnabled,
+		HTTPEnabled:        hc.HTTP.Enabled,
+		HTTPIp:             hc.HTTP.IP,
+		HTTPPort:           hc.HTTP.Port,
+		WSEnabled:          hc.WS.Enabled,
+		WSIp:               hc.WS.IP,
+		WSPort:             hc.WS.Port,
+		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