Issue168: fix es-node crash when --p2p.disable set

README.md

@@ -91,7 +91,7 @@ The full list of options that you can use to configure an es-node are as follows
 |`--p2p.advertise.udp`|The UDP port to advertise in Discv5 as fallback if not determined by Discv5, put into the ENR of the node. Set to p2p.listen.udp value if 0.|`0`||
 |`--p2p.ban.peers`|Enables peer banning. This should ONLY be enabled once certain peer scoring is working correctly.|||
 |`--p2p.bootnodes`|Comma-separated base64-format ENR list. Bootnodes to start discovering other node records from.|||
-|`--p2p.disable`|Completely disable the P2P stack|||
+|`--p2p.disable`|Completely disable the P2P stack, if P2P is disabled, mining will not start automatically.|||
 |`--p2p.discovery.path`|Discovered ENRs are persisted in a database to recover from a restart without having to bootstrap the discovery process again. Set to 'memory' to never persist the peerstore.|`esnode_discovery_db`||
 |`--p2p.listen.ip`|IP to bind LibP2P and Discv5 to|`0.0.0.0`||
 |`--p2p.listen.tcp`|TCP port to bind LibP2P to. Any available system port if set to 0.|`9222`||

ethstorage/flags/p2p_flags.go

@@ -14,7 +14,7 @@ func p2pEnv(v string) string {
 var (
 	DisableP2P = cli.BoolFlag{
 		Name:     "p2p.disable",
-		Usage:    "Completely disable the P2P stack",
+		Usage:    "Completely disable the P2P stack, if P2P is disabled, mining will not start automatically.",
 		Required: false,
 		EnvVar:   p2pEnv("DISABLE"),
 	}

ethstorage/node/node.go

@@ -272,9 +272,11 @@ func (n *EsNode) Start(ctx context.Context, cfg *Config) error {
 		return err
 	}
 
-	if err := n.p2pNode.Start(); err != nil {
-		n.log.Error("Could not start a p2pNode", "err", err)
-		return err
+	if n.p2pNode != nil {
+		if err := n.p2pNode.Start(); err != nil {
+			n.log.Error("Could not start a p2pNode", "err", err)
+			return err
+		}
 	}
 
 	return nil

ethstorage/p2p/node.go

@@ -229,7 +229,10 @@ func (n *NodeP2P) ConnectionManager() connmgr.ConnManager {
 }
 
 func (n *NodeP2P) Start() error {
-	return n.syncCl.Start()
+	if n.syncCl != nil {
+		return n.syncCl.Start()
+	}
+	return nil
 }
 
 func (n *NodeP2P) Close() error {