P2P handshake handling

beacon-chain/node/BUILD.bazel

@@ -3,6 +3,7 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "fetch_contract_address.go",
         "node.go",
         "p2p_config.go",
     ],

beacon-chain/node/fetch_contract_address.go

@@ -0,0 +1,41 @@
+package node
+
+import (
+	"io/ioutil"
+	"net/http"
+	"sync"
+
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+var cachedDepositAddress string
+var fetchLock sync.Mutex
+
+// fetchDepositContract from the cluster endpoint.
+func fetchDepositContract() (string, error) {
+	fetchLock.Lock()
+	defer fetchLock.Unlock()
+
+	if cachedDepositAddress != "" {
+		return cachedDepositAddress, nil
+	}
+
+	log.WithField(
+		"endpoint",
+		params.BeaconConfig().TestnetContractEndpoint,
+	).Info("Fetching testnet cluster address")
+	resp, err := http.Get(params.BeaconConfig().TestnetContractEndpoint)
+	if err != nil {
+		return "", err
+	}
+	contractResponse, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+	if err := resp.Body.Close(); err != nil {
+		return "", err
+	}
+
+	cachedDepositAddress = string(contractResponse)
+	return cachedDepositAddress, nil
+}

beacon-chain/node/node.go

@@ -4,8 +4,6 @@ package node
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
-	"net/http"
 	"os"
 	"os/signal"
 	"path"
@@ -248,22 +246,11 @@ func (b *BeaconNode) registerPOWChainService(cliCtx *cli.Context) error {
 	depAddress := cliCtx.GlobalString(utils.DepositContractFlag.Name)
 
 	if depAddress == "" {
-		log.Infof("Fetching testnet cluster address from %s...", params.BeaconConfig().TestnetContractEndpoint)
-		resp, err := http.Get(params.BeaconConfig().TestnetContractEndpoint)
+		var err error
+		depAddress, err = fetchDepositContract()
 		if err != nil {
-			log.Fatalf("Could not get latest deposit contract address: %v", err)
+			log.WithError(err).Fatal("Cannot fetch deposit contract")
 		}
-		defer func() {
-			if err := resp.Body.Close(); err != nil {
-				log.Fatal(err)
-			}
-		}()
-
-		contractResponse, err := ioutil.ReadAll(resp.Body)
-		if err != nil {
-			log.Fatal(err)
-		}
-		depAddress = string(contractResponse)
 	}
 
 	if !common.IsHexAddress(depAddress) {

beacon-chain/node/p2p_config.go

@@ -2,6 +2,7 @@ package node
 
 import (
 	"github.com/gogo/protobuf/proto"
+	"github.com/prysmaticlabs/prysm/beacon-chain/utils"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/cmd"
 	"github.com/prysmaticlabs/prysm/shared/p2p"
@@ -27,11 +28,21 @@ var topicMappings = map[pb.Topic]proto.Message{
 }
 
 func configureP2P(ctx *cli.Context) (*p2p.Server, error) {
+	contractAddress := ctx.GlobalString(utils.DepositContractFlag.Name)
+	if contractAddress == "" {
+		var err error
+		contractAddress, err = fetchDepositContract()
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	s, err := p2p.NewServer(&p2p.ServerConfig{
-		NoDiscovery:       ctx.GlobalBool(cmd.NoDiscovery.Name),
-		BootstrapNodeAddr: ctx.GlobalString(cmd.BootstrapNode.Name),
-		RelayNodeAddr:     ctx.GlobalString(cmd.RelayNode.Name),
-		Port:              ctx.GlobalInt(cmd.P2PPort.Name),
+		NoDiscovery:            ctx.GlobalBool(cmd.NoDiscovery.Name),
+		BootstrapNodeAddr:      ctx.GlobalString(cmd.BootstrapNode.Name),
+		RelayNodeAddr:          ctx.GlobalString(cmd.RelayNode.Name),
+		Port:                   ctx.GlobalInt(cmd.P2PPort.Name),
+		DepositContractAddress: contractAddress,
 	})
 	if err != nil {
 		return nil, err