Add cgroup manage for mocking of package resources

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cgroups.go

@@ -0,0 +1,41 @@
+package libcontainer
+
+import (
+	"github.com/docker/libcontainer/cgroups"
+	"github.com/docker/libcontainer/cgroups/fs"
+	"github.com/docker/libcontainer/cgroups/systemd"
+)
+
+type CgroupManager interface {
+	GetPids(*cgroups.Cgroup) ([]int, error)
+	GetStats(*cgroups.Cgroup) (*cgroups.Stats, error)
+}
+
+func newCgroupsManager() CgroupManager {
+	if systemd.UseSystemd() {
+		return &systemdCgroupManager{}
+	}
+	return &fsCgroupsManager{}
+}
+
+type systemdCgroupManager struct {
+}
+
+func (m *systemdCgroupManager) GetPids(config *cgroups.Cgroup) ([]int, error) {
+	return systemd.GetPids(config)
+}
+
+func (m *systemdCgroupManager) GetStats(config *cgroups.Cgroup) (*cgroups.Stats, error) {
+	return systemd.GetStats(config)
+}
+
+type fsCgroupsManager struct {
+}
+
+func (m *fsCgroupsManager) GetPids(config *cgroups.Cgroup) ([]int, error) {
+	return fs.GetPids(config)
+}
+
+func (m *fsCgroupsManager) GetStats(config *cgroups.Cgroup) (*cgroups.Stats, error) {
+	return fs.GetStats(config)
+}

container.go

@@ -12,7 +12,7 @@ type ContainerInfo interface {
 	// errors:
 	// ContainerDestroyed - Container no longer exists,
 	// Systemerror - System error.
-	RunState() (*RunState, error)
+	RunState() (RunState, error)
 
 	// Returns the current config of the container.
 	Config() *Config

linux_container.go

@@ -2,17 +2,14 @@
 
 package libcontainer
 
-import (
-	"github.com/docker/libcontainer/cgroups/fs"
-	"github.com/docker/libcontainer/cgroups/systemd"
-	"github.com/docker/libcontainer/network"
-)
+import "github.com/docker/libcontainer/network"
 
 type linuxContainer struct {
 	id            string
 	root          string
 	config        *Config
 	state         *State
+	cgroupManager CgroupManager
 }
 
 func (c *linuxContainer) ID() string {
@@ -23,21 +20,12 @@ func (c *linuxContainer) Config() *Config {
 	return c.config
 }
 
-func (c *linuxContainer) RunState() (*RunState, error) {
+func (c *linuxContainer) RunState() (RunState, error) {
 	panic("not implemented")
 }
 
 func (c *linuxContainer) Processes() ([]int, error) {
-	var (
-		err  error
-		pids []int
-	)
-
-	if systemd.UseSystemd() {
-		pids, err = systemd.GetPids(c.config.Cgroups)
-	} else {
-		pids, err = fs.GetPids(c.config.Cgroups)
-	}
+	pids, err := c.cgroupManager.GetPids(c.config.Cgroups)
 	if err != nil {
 		return nil, newGenericError(err, SystemError)
 	}
@@ -50,15 +38,9 @@ func (c *linuxContainer) Stats() (*ContainerStats, error) {
 		stats = &ContainerStats{}
 	)
 
-	if systemd.UseSystemd() {
-		stats.CgroupStats, err = systemd.GetStats(c.config.Cgroups)
-	} else {
-		stats.CgroupStats, err = fs.GetStats(c.config.Cgroups)
-	}
-	if err != nil {
+	if stats.CgroupStats, err = c.cgroupManager.GetStats(c.config.Cgroups); err != nil {
 		return stats, newGenericError(err, SystemError)
 	}
-
 	if stats.NetworkStats, err = network.GetStats(&c.state.NetworkState); err != nil {
 		return stats, newGenericError(err, SystemError)
 	}

linux_container_test.go

@@ -0,0 +1,68 @@
+// +build linux
+
+package libcontainer
+
+import (
+	"testing"
+
+	"github.com/docker/libcontainer/cgroups"
+)
+
+type mockCgroupManager struct {
+	pids  []int
+	stats *cgroups.Stats
+}
+
+func (m *mockCgroupManager) GetPids(config *cgroups.Cgroup) ([]int, error) {
+	return m.pids, nil
+}
+
+func (m *mockCgroupManager) GetStats(config *cgroups.Cgroup) (*cgroups.Stats, error) {
+	return m.stats, nil
+}
+
+func TestGetContainerPids(t *testing.T) {
+	container := &linuxContainer{
+		id:            "myid",
+		config:        &Config{},
+		cgroupManager: &mockCgroupManager{pids: []int{1, 2, 3}},
+	}
+
+	pids, err := container.Processes()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, expected := range []int{1, 2, 3} {
+		if pids[i] != expected {
+			t.Fatalf("expected pid %d but received %d", expected, pids[i])
+		}
+	}
+}
+
+func TestGetContainerStats(t *testing.T) {
+	container := &linuxContainer{
+		id:     "myid",
+		config: &Config{},
+		cgroupManager: &mockCgroupManager{
+			pids: []int{1, 2, 3},
+			stats: &cgroups.Stats{
+				MemoryStats: cgroups.MemoryStats{
+					Usage: 1024,
+				},
+			},
+		},
+		state: &State{},
+	}
+
+	stats, err := container.Stats()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stats.CgroupStats == nil {
+		t.Fatal("cgroup stats are nil")
+	}
+	if stats.CgroupStats.MemoryStats.Usage != 1024 {
+		t.Fatalf("expected memory usage 1024 but recevied %d", stats.CgroupStats.MemoryStats.Usage)
+	}
+}

linux_factory.go

@@ -51,6 +51,7 @@ func (l *linuxFactory) Load(id string) (ContainerInfo, error) {
 		root:          containerRoot,
 		config:        config,
 		state:         state,
+		cgroupManager: newCgroupsManager(),
 	}, nil
 }
 

state.go

@@ -31,7 +31,7 @@ const (
 	stateFile = "state.json"
 
 	// The container exists and is running.
-	Running RunState = iota
+	Running RunState = iota + 1
 
 	// The container exists, it is in the process of being paused.
 	Pausing