removed subshelling for link creation (#209)

* removed subshelling for link creation

* optimized netns symlink creation

* removed debug messages

* addressed review comments

* combined createveth functions

* improved logging messages

clab/config.go

@@ -21,7 +21,7 @@ const (
 	dockerNetIPv4Addr = "172.20.20.0/24"
 	dockerNetIPv6Addr = "2001:172:20:20::/80"
 	dockerNetMTU      = "1450"
-	srlDefaultType = "ixr6"
+	srlDefaultType    = "ixr6"
 )
 
 // supported kinds
@@ -119,12 +119,14 @@ type Node struct {
 	TLSCert              string
 	TLSKey               string
 	TLSAnchor            string
+	NSPath               string // network namespace path for this node
 }
 
 // Link is a struct that contains the information of a link between 2 containers
 type Link struct {
 	A      *Endpoint
 	B      *Endpoint
+	MTU    int
 	Labels map[string]string
 }
 
@@ -470,6 +472,10 @@ func (c *cLab) NewLink(l LinkConfig) *Link {
 	link := new(Link)
 	link.Labels = l.Labels
 
+	if link.MTU <= 0 {
+		link.MTU = 1500
+	}
+
 	for i, d := range l.Endpoints {
 		// i indicates the number and d presents the string, which need to be
 		// split in node and endpoint name

clab/docker.go

@@ -23,8 +23,7 @@ const sysctlBase = "/proc/sys"
 
 // CreateBridge creates a docker bridge
 func (c *cLab) CreateBridge(ctx context.Context) (err error) {
-	log.Info("Creating docker bridge")
-	log.Debugf("Creating docker bridge: Name: %s, IPv4Subnet: '%s', IPv6Subnet: '%s", c.Config.Mgmt.Network, c.Config.Mgmt.IPv4Subnet, c.Config.Mgmt.IPv6Subnet)
+	log.Infof("Creating docker network: Name='%s', IPv4Subnet='%s', IPv6Subnet='%s'", c.Config.Mgmt.Network, c.Config.Mgmt.IPv4Subnet, c.Config.Mgmt.IPv6Subnet)
 
 	enableIPv6 := false
 	var ipamConfig []network.IPAMConfig
@@ -144,7 +143,7 @@ func (c *cLab) DeleteBridge(ctx context.Context) (err error) {
 
 // CreateContainer creates a docker container
 func (c *cLab) CreateContainer(ctx context.Context, node *Node) (err error) {
-	log.Infof("Create container: %s", node.ShortName)
+	log.Infof("Creating container: %s", node.ShortName)
 
 	err = c.PullImageIfRequired(ctx, node.Image)
 	if err != nil {
@@ -212,7 +211,8 @@ func (c *cLab) CreateContainer(ctx context.Context, node *Node) (err error) {
 	if err != nil {
 		return err
 	}
-	return linkContainerNS(cJSON.State.Pid, node.LongName)
+	node.NSPath = "/proc/" + strconv.Itoa(cJSON.State.Pid) + "/ns/net"
+	return linkContainerNS(node.NSPath, node.LongName)
 }
 
 func (c *cLab) PullImageIfRequired(ctx context.Context, imageName string) error {
@@ -345,13 +345,14 @@ func (c *cLab) DeleteContainer(ctx context.Context, name string) error {
 	var err error
 	force := !c.gracefulShutdown
 	if c.gracefulShutdown {
+		log.Infof("Stopping container: %s", name)
 		err = c.DockerClient.ContainerStop(ctx, name, &c.timeout)
 		if err != nil {
 			log.Errorf("could not stop container '%s': %v", name, err)
 			force = true
 		}
 	}
-	log.Infof("Removing container: %s", name)
+	log.Debugf("Removing container: %s", name)
 	err = c.DockerClient.ContainerRemove(ctx, name, types.ContainerRemoveOptions{Force: force})
 	if err != nil {
 		return err
@@ -362,11 +363,10 @@ func (c *cLab) DeleteContainer(ctx context.Context, name string) error {
 
 // linkContainerNS creates a symlink for containers network namespace
 // so that it can be managed by iproute2 utility
-func linkContainerNS(pid int, containerName string) error {
+func linkContainerNS(nspath string, containerName string) error {
 	CreateDirectory("/run/netns/", 0755)
-	src := "/proc/" + strconv.Itoa(pid) + "/ns/net"
 	dst := "/run/netns/" + containerName
-	err := os.Symlink(src, dst)
+	err := os.Symlink(nspath, dst)
 	if err != nil {
 		return err
 	}

clab/file.go

@@ -144,7 +144,7 @@ func (c *cLab) CreateNodeDirStructure(node *Node) (err error) {
 
 	switch node.Kind {
 	case "srl":
-		log.Infof("Create directory structure for SRL container: %s", node.ShortName)
+		log.Debugf("Creating directory structure for SRL container: %s", node.ShortName)
 		var src string
 		var dst string