Ping constructor option, enabled by default

config/config.go

@@ -56,6 +56,9 @@ type Config struct {
 	NATManager  NATManagerC
 	Peerstore   pstore.Peerstore
 	Reporter    metrics.Reporter
+
+	PingCustom bool
+	Ping       bool
 }
 
 // NewNode constructs a new libp2p Host from the Config.
@@ -102,6 +105,7 @@ func (cfg *Config) NewNode(ctx context.Context) (host.Host, error) {
 		ConnManager:  cfg.ConnManager,
 		AddrsFactory: cfg.AddrsFactory,
 		NATManager:   cfg.NATManager,
+		EnablePing:   cfg.Ping,
 	})
 	if err != nil {
 		swrm.Close()

defaults.go

@@ -75,6 +75,11 @@ var DefaultEnableRelay = func(cfg *Config) error {
 	return cfg.Apply(EnableRelay())
 }
 
+// DefaultEnablePing enables the ping service by default
+var DefaultEnablePing = func(cfg *Config) error {
+	return cfg.Apply(Ping(true))
+}
+
 // Complete list of default options and when to fallback on them.
 //
 // Please *DON'T* specify default options any other way. Putting this all here
@@ -111,6 +116,10 @@ var defaults = []struct {
 		fallback: func(cfg *Config) bool { return !cfg.RelayCustom },
 		opt:      DefaultEnableRelay,
 	},
+	{
+		fallback: func(cfg *Config) bool { return !cfg.PingCustom },
+		opt:      DefaultEnablePing,
+	},
 }
 
 // Defaults configures libp2p to use the default options. Can be combined with

options.go

@@ -252,6 +252,15 @@ func NATManager(nm config.NATManagerC) Option {
 	}
 }
 
+// Ping will configure libp2p to support the ping service; enable by default.
+func Ping(enable bool) Option {
+	return func(cfg *Config) error {
+		cfg.PingCustom = true
+		cfg.Ping = enable
+		return nil
+	}
+}
+
 // NoListenAddrs will configure libp2p to not listen by default.
 //
 // This will both clear any configured listen addrs and prevent libp2p from