[rpc] use a public_rpc parameter to enable public rpc

This is to fix the AWS ec2 instance no real public IP issue.

Signed-off-by: Leo Chen <leo@harmony.one>

cmd/harmony/main.go

@@ -124,6 +124,8 @@ var (
 	metricsFlag     = flag.Bool("metrics", false, "Collect and upload node metrics")
 	pushgatewayIP   = flag.String("pushgateway_ip", "grafana.harmony.one", "Metrics view ip")
 	pushgatewayPort = flag.String("pushgateway_port", "9091", "Metrics view port")
+
+	publicRPC = flag.Bool("public_rpc", false, "Enable Public RPC Access (default: false)")
 )
 
 func initSetup() {
@@ -406,6 +408,7 @@ func main() {
 		os.Exit(1)
 	}
 
+	nodeconfig.SetPublicRPC(*publicRPC)
 	nodeconfig.SetVersion(fmt.Sprintf("Harmony (C) 2019. %v, version %v-%v (%v %v)", path.Base(os.Args[0]), version, commit, builtBy, builtAt))
 	if *versionFlag {
 		printVersion()

internal/configs/node/config.go

@@ -63,6 +63,7 @@ const (
 )
 
 var version string
+var publicRPC bool // enable public RPC access
 
 // ConfigType is the structure of all node related configuration variables
 type ConfigType struct {
@@ -252,3 +253,13 @@ func GetVersion() string {
 func GetTempDir() string {
 	return os.TempDir()
 }
+
+// SetPublicRPC set the boolean value of public RPC access
+func SetPublicRPC(v bool) {
+	publicRPC = v
+}
+
+// GetPublicRPC get the boolean value of public RPC access
+func GetPublicRPC() bool {
+	return publicRPC
+}

node/rpc.go

@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 
 	"github.com/harmony-one/harmony/hmy"
+	nodeconfig "github.com/harmony-one/harmony/internal/configs/node"
 	"github.com/harmony-one/harmony/internal/hmyapi"
 	"github.com/harmony-one/harmony/internal/hmyapi/filters"
 	"github.com/harmony-one/harmony/internal/utils"
@@ -56,12 +57,17 @@ func (node *Node) StartRPC(nodePort string) error {
 
 	port, _ := strconv.Atoi(nodePort)
 
-	httpEndpoint = fmt.Sprintf(":%v", port+rpcHTTPPortOffset)
+	ip := ""
+	if !nodeconfig.GetPublicRPC() {
+		ip = "127.0.0.1"
+	}
+	httpEndpoint = fmt.Sprintf("%v:%v", ip, port+rpcHTTPPortOffset)
+
 	if err := node.startHTTP(httpEndpoint, apis, httpModules, httpOrigins, httpVirtualHosts, httpTimeouts); err != nil {
 		return err
 	}
 
-	wsEndpoint = fmt.Sprintf(":%v", port+rpcWSPortOffset)
+	wsEndpoint = fmt.Sprintf("%v:%v", ip, port+rpcWSPortOffset)
 	if err := node.startWS(wsEndpoint, apis, wsModules, wsOrigins, true); err != nil {
 		node.stopHTTP()
 		return err