*: constify cgroups stuff

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

libkpod/config.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 
 	"github.com/BurntSushi/toml"
+	"github.com/kubernetes-incubator/cri-o/oci"
 	"github.com/opencontainers/selinux/go-selinux"
 )
 
@@ -20,7 +21,7 @@ const (
 	apparmorProfileName = "crio-default"
 	cniConfigDir        = "/etc/cni/net.d/"
 	cniBinDir           = "/opt/cni/bin/"
-	cgroupManager       = "cgroupfs"
+	cgroupManager       = oci.CgroupfsCgroupsManager
 	lockPath            = "/run/crio.lock"
 	containerExitsDir   = "/var/run/kpod/exits"
 )

oci/oci.go

@@ -30,6 +30,11 @@ const (
 	ContainerStateStopped = "stopped"
 	// ContainerCreateTimeout represents the value of container creating timeout
 	ContainerCreateTimeout = 10 * time.Second
+
+	// CgroupfsCgroupsManager represents cgroupfs native cgroup manager
+	CgroupfsCgroupsManager = "cgroupfs"
+	// SystemdCgroupsManager represents systemd native cgroup manager
+	SystemdCgroupsManager = "systemd"
 )
 
 // New creates a new Runtime with options provided
@@ -141,7 +146,7 @@ func (r *Runtime) CreateContainer(c *Container, cgroupParent string) error {
 	defer parentStartPipe.Close()
 
 	var args []string
-	if r.cgroupManager == "systemd" {
+	if r.cgroupManager == SystemdCgroupsManager {
 		args = append(args, "-s")
 	}
 	args = append(args, "-c", c.id)
@@ -187,7 +192,7 @@ func (r *Runtime) CreateContainer(c *Container, cgroupParent string) error {
 	childStartPipe.Close()
 
 	// Move conmon to specified cgroup
-	if r.cgroupManager == "systemd" {
+	if r.cgroupManager == SystemdCgroupsManager {
 		logrus.Infof("Running conmon under slice %s and unitName %s", cgroupParent, createUnitName("crio-conmon", c.id))
 		if err = utils.RunUnderSystemdScope(cmd.Process.Pid, cgroupParent, createUnitName("crio-conmon", c.id)); err != nil {
 			logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err)

server/container_create.go

@@ -38,6 +38,10 @@ const (
 	seccompUnconfined      = "unconfined"
 	seccompRuntimeDefault  = "runtime/default"
 	seccompLocalhostPrefix = "localhost/"
+
+	scopePrefix           = "crio"
+	defaultCgroupfsParent = "/crio"
+	defaultSystemdParent  = "system.slice"
 )
 
 func addOCIBindMounts(sb *sandbox.Sandbox, containerConfig *pb.ContainerConfig, specgen *generate.Generator) ([]oci.ContainerVolume, error) {
@@ -472,11 +476,10 @@ func (s *Server) createSandboxContainer(ctx context.Context, containerID string,
 		}
 
 		var cgPath string
-		scopePrefix := "crio"
-		parent := "/crio"
-		useSystemd := s.config.CgroupManager == "systemd"
+		parent := defaultCgroupfsParent
+		useSystemd := s.config.CgroupManager == oci.SystemdCgroupsManager
 		if useSystemd {
-			parent = "system.slice"
+			parent = defaultSystemdParent
 		}
 		if sb.CgroupParent() != "" {
 			parent = sb.CgroupParent()

server/sandbox_run.go

@@ -325,7 +325,7 @@ func (s *Server) RunPodSandbox(ctx context.Context, req *pb.RunPodSandboxRequest
 	// setup cgroup settings
 	cgroupParent := req.GetConfig().GetLinux().CgroupParent
 	if cgroupParent != "" {
-		if s.config.CgroupManager == "systemd" {
+		if s.config.CgroupManager == oci.SystemdCgroupsManager {
 			cgPath, err := convertCgroupNameToSystemd(cgroupParent, false)
 			if err != nil {
 				return nil, err