Add option to enable networkDB debug

Add a new configuration option to allow the enabling
of the networkDB debug. The option is only parsed using the
reload event. This will protect the daemon on start or restart
if the option is left behind in the config file

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>

cmd/dockerd/config.go

@@ -59,6 +59,8 @@ func installCommonConfigFlags(conf *config.Config, flags *pflag.FlagSet) {
 	flags.IntVar(&maxConcurrentDownloads, "max-concurrent-downloads", config.DefaultMaxConcurrentDownloads, "Set the max concurrent downloads for each pull")
 	flags.IntVar(&maxConcurrentUploads, "max-concurrent-uploads", config.DefaultMaxConcurrentUploads, "Set the max concurrent uploads for each push")
 	flags.IntVar(&conf.ShutdownTimeout, "shutdown-timeout", defaultShutdownTimeout, "Set the default shutdown timeout")
+	flags.IntVar(&conf.NetworkDiagnosticPort, "network-diagnostic-port", 0, "TCP port number of the network diagnostic server")
+	flags.MarkHidden("network-diagnostic-port")
 
 	flags.StringVar(&conf.SwarmDefaultAdvertiseAddr, "swarm-default-advertise-addr", "", "Set default address or interface for swarm advertised address")
 	flags.BoolVar(&conf.Experimental, "experimental", false, "Enable experimental features")

daemon/config/config.go

@@ -98,6 +98,7 @@ type CommonConfig struct {
 	GraphOptions          []string                  `json:"storage-opts,omitempty"`
 	Labels                []string                  `json:"labels,omitempty"`
 	Mtu                   int                       `json:"mtu,omitempty"`
+	NetworkDiagnosticPort int                       `json:"network-diagnostic-port,omitempty"`
 	Pidfile               string                    `json:"pidfile,omitempty"`
 	RawLogs               bool                      `json:"raw-logs,omitempty"`
 	RootDeprecated        string                    `json:"graph,omitempty"`

daemon/reload.go

@@ -61,6 +61,9 @@ func (daemon *Daemon) Reload(conf *config.Config) (err error) {
 	if err := daemon.reloadLiveRestore(conf, attributes); err != nil {
 		return err
 	}
+	if err := daemon.reloadNetworkDiagnosticPort(conf, attributes); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -308,3 +311,18 @@ func (daemon *Daemon) reloadLiveRestore(conf *config.Config, attributes map[stri
 	attributes["live-restore"] = fmt.Sprintf("%t", daemon.configStore.LiveRestoreEnabled)
 	return nil
 }
+
+// reloadNetworkDiagnosticPort updates the network controller starting the diagnose mode if the config is valid
+func (daemon *Daemon) reloadNetworkDiagnosticPort(conf *config.Config, attributes map[string]string) error {
+	if conf == nil || daemon.netController == nil {
+		return nil
+	}
+	// Enable the network diagnose if the flag is set with a valid port withing the range
+	if conf.IsValueSet("network-diagnostic-port") && conf.NetworkDiagnosticPort > 0 && conf.NetworkDiagnosticPort < 65536 {
+		logrus.Warnf("Calling the diagnostic start with %d", conf.NetworkDiagnosticPort)
+		daemon.netController.StartDiagnose(conf.NetworkDiagnosticPort)
+	} else {
+		daemon.netController.StopDiagnose()
+	}
+	return nil
+}

daemon/reload_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/docker/docker/pkg/discovery"
 	_ "github.com/docker/docker/pkg/discovery/memory"
 	"github.com/docker/docker/registry"
+	"github.com/docker/libnetwork"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -479,3 +480,71 @@ func TestDaemonDiscoveryReloadOnlyClusterAdvertise(t *testing.T) {
 		t.Fatal(e)
 	}
 }
+
+func TestDaemonReloadNetworkDiagnosticPort(t *testing.T) {
+	daemon := &Daemon{}
+	daemon.configStore = &config.Config{}
+
+	valuesSet := make(map[string]interface{})
+	valuesSet["network-diagnostic-port"] = 2000
+	enableConfig := &config.Config{
+		CommonConfig: config.CommonConfig{
+			NetworkDiagnosticPort: 2000,
+			ValuesSet:             valuesSet,
+		},
+	}
+	disableConfig := &config.Config{
+		CommonConfig: config.CommonConfig{},
+	}
+
+	netOptions, err := daemon.networkOptions(enableConfig, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	controller, err := libnetwork.New(netOptions...)
+	if err != nil {
+		t.Fatal(err)
+	}
+	daemon.netController = controller
+
+	// Enable/Disable the server for some iterations
+	for i := 0; i < 10; i++ {
+		enableConfig.CommonConfig.NetworkDiagnosticPort++
+		if err := daemon.Reload(enableConfig); err != nil {
+			t.Fatal(err)
+		}
+		// Check that the diagnose is enabled
+		if !daemon.netController.IsDiagnoseEnabled() {
+			t.Fatalf("diagnosed should be enable")
+		}
+
+		// Reload
+		if err := daemon.Reload(disableConfig); err != nil {
+			t.Fatal(err)
+		}
+		// Check that the diagnose is disabled
+		if daemon.netController.IsDiagnoseEnabled() {
+			t.Fatalf("diagnosed should be disable")
+		}
+	}
+
+	enableConfig.CommonConfig.NetworkDiagnosticPort++
+	// 2 times the enable should not create problems
+	if err := daemon.Reload(enableConfig); err != nil {
+		t.Fatal(err)
+	}
+	// Check that the diagnose is enabled
+	if !daemon.netController.IsDiagnoseEnabled() {
+		t.Fatalf("diagnosed should be enable")
+	}
+
+	// Check that another reload does not cause issues
+	if err := daemon.Reload(enableConfig); err != nil {
+		t.Fatal(err)
+	}
+	// Check that the diagnose is enable
+	if !daemon.netController.IsDiagnoseEnabled() {
+		t.Fatalf("diagnosed should be enable")
+	}
+
+}