v1/stats: add all fields of memory.oom_control

This adds memory.oom_control fields within v1/stats. Stats/v2
already has such fields under memory.events file. This uses
similar approach as stats/v2 while adding oom_control fields for
v1 memory controller.

Signed-off-by: Vishal Verma <verma.vishal1989@gmail.com>

Author: vermavis

memory.go

@@ -248,18 +248,28 @@ func (m *memoryController) Update(path string, resources *specs.LinuxResources)
 }
 
 func (m *memoryController) Stat(path string, stats *v1.Metrics) error {
-	f, err := os.Open(filepath.Join(m.Path(path), "memory.stat"))
+	fMemStat, err := os.Open(filepath.Join(m.Path(path), "memory.stat"))
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer fMemStat.Close()
 	stats.Memory = &v1.MemoryStat{
 		Usage:     &v1.MemoryEntry{},
 		Swap:      &v1.MemoryEntry{},
 		Kernel:    &v1.MemoryEntry{},
 		KernelTCP: &v1.MemoryEntry{},
 	}
-	if err := m.parseStats(f, stats.Memory); err != nil {
+	if err := m.parseStats(fMemStat, stats.Memory); err != nil {
+		return err
+	}
+
+	fMemOomControl, err := os.Open(filepath.Join(m.Path(path), "memory.oom_control"))
+	if err != nil {
+		return err
+	}
+	defer fMemOomControl.Close()
+	stats.MemoryOomControl = &v1.MemoryOomControl{}
+	if err := m.parseOomControlStats(fMemOomControl, stats.MemoryOomControl); err != nil {
 		return err
 	}
 	for _, t := range []struct {
@@ -374,6 +384,29 @@ func (m *memoryController) parseStats(r io.Reader, stat *v1.MemoryStat) error {
 	return nil
 }
 
+func (m *memoryController) parseOomControlStats(r io.Reader, stat *v1.MemoryOomControl) error {
+	var (
+		raw  = make(map[string]uint64)
+		sc   = bufio.NewScanner(r)
+		line int
+	)
+	for sc.Scan() {
+		key, v, err := parseKV(sc.Text())
+		if err != nil {
+			return fmt.Errorf("%d: %v", line, err)
+		}
+		raw[key] = v
+		line++
+	}
+	if err := sc.Err(); err != nil {
+		return err
+	}
+	stat.OomKillDisable = raw["oom_kill_disable"]
+	stat.UnderOom = raw["under_oom"]
+	stat.OomKill = raw["oom_kill"]
+	return nil
+}
+
 func (m *memoryController) set(path string, settings []memorySettings) error {
 	for _, t := range settings {
 		if t.value != nil {

memory_test.go

@@ -61,6 +61,11 @@ total_active_file 31
 total_unevictable 32
 `
 
+const memoryOomControlData = `oom_kill_disable 1
+under_oom 2
+oom_kill 3
+`
+
 func TestParseMemoryStats(t *testing.T) {
 	var (
 		c = &memoryController{}
@@ -111,6 +116,27 @@ func TestParseMemoryStats(t *testing.T) {
 	}
 }
 
+func TestParseMemoryOomControl(t *testing.T) {
+	var (
+		c = &memoryController{}
+		m = &v1.MemoryOomControl{}
+		r = strings.NewReader(memoryOomControlData)
+	)
+	if err := c.parseOomControlStats(r, m); err != nil {
+		t.Fatal(err)
+	}
+	index := []uint64{
+		m.OomKillDisable,
+		m.UnderOom,
+		m.OomKill,
+	}
+	for i, v := range index {
+		if v != uint64(i)+1 {
+			t.Errorf("expected value at index %d to be %d but received %d", i, i+1, v)
+		}
+	}
+}
+
 func TestMemoryController_Stat(t *testing.T) {
 	// GIVEN a cgroups folder with all the memory metrics
 	modules := []string{"", "memsw", "kmem", "kmem.tcp"}
@@ -244,6 +270,9 @@ func buildMemoryMetrics(t *testing.T, modules []string, metrics []string) string
 	if err := ioutil.WriteFile(path.Join(tmpDir, "memory.stat"), []byte(memoryData), defaultFilePerm); err != nil {
 		t.Fatal(err)
 	}
+	if err := ioutil.WriteFile(path.Join(tmpDir, "memory.oom_control"), []byte(memoryOomControlData), defaultFilePerm); err != nil {
+		t.Fatal(err)
+	}
 	cnt := 0
 	for _, mod := range modules {
 		for _, metric := range metrics {