reviving code from #1447 to a new branch

plugins/inputs/system/HUGEPAGES.md

@@ -0,0 +1,35 @@
+# Hugepages Input Plugin
+
+The hugepages plugin gathers hugepages metrics including per NUMA node
+
+### Configuration:
+
+```toml
+# Description
+[[inputs.hugepages]]
+    ## Path to a NUMA nodes 
+    # numa_node_path = "/sys/devices/system/node"
+    ## Path to a meminfo file
+    # meminfo_path = "/proc/meminfo"
+```
+
+### Measurements & Fields:
+
+- hugepages
+    - free (int, kB)
+    - nr (int, kB)
+    - HugePages_Total (int, kB)
+    - HugePages_Free (int, kB)
+
+### Tags:
+
+- hugepages has the following tags:
+    - node
+
+### Example Output:
+
+```
+$ ./telegraf -config telegraf.conf -input-filter hugepages -test
+> hugepages,host=maxpc,node=node0 free=0i,nr=0i 1467618621000000000
+> hugepages,host=maxpc,name=meminfo HugePages_Free=0i,HugePages_Total=0i 1467618621000000000
+```

plugins/inputs/system/hugepages.go

@@ -0,0 +1,184 @@
+package system
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"strconv"
+	"strings"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+var (
+	newlineByte     = []byte("\n")
+	colonByte       = []byte(":")
+	kbPrecisionByte = []byte("kB")
+)
+
+// default file paths
+const (
+	// the path where statistics are kept per NUMA nodes
+	NUMA_NODE_PATH = "/sys/devices/system/node"
+	// the path to the meminfo file which is produced by kernel
+	MEMINFO_PATH = "/proc/meminfo"
+
+	// hugepages stat field names on meminfo file
+	HUGE_PAGES_TOTAL = "HugePages_Total"
+	HUGE_PAGES_FREE  = "HugePages_Free"
+)
+
+var hugepagesSampleConfig = `
+  ## Path to a NUMA nodes
+  # numa_node_path = "/sys/devices/system/node"
+  ## Path to a meminfo file
+  # meminfo_path = "/proc/meminfo"
+`
+
+// Mem is the
+type Hugepages struct {
+	NUMANodePath string `toml:"numa_node_path"`
+	MeminfoPath  string `toml:"meminfo_path"`
+}
+
+func (mem *Hugepages) Description() string {
+	return "Collects hugepages metrics from kernel and per NUMA node"
+}
+
+func (mem *Hugepages) SampleConfig() string {
+	return hugepagesSampleConfig
+}
+
+func (mem *Hugepages) Gather(acc telegraf.Accumulator) error {
+	mem.loadPaths()
+	err := mem.GatherStatsPerNode(acc)
+	if err != nil {
+		return err
+	}
+
+	err = mem.GatherStatsFromMeminfo(acc)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// GatherHugepagesStatsPerNode collects hugepages stats per NUMA nodes
+func (mem *Hugepages) GatherStatsPerNode(acc telegraf.Accumulator) error {
+	numaNodeMetrics, err := statsPerNUMA(mem.NUMANodePath)
+	if err != nil {
+		return err
+	}
+
+	for k, v := range numaNodeMetrics {
+		metrics := make(map[string]interface{})
+		tags := map[string]string{
+			"node": k,
+		}
+		metrics["free"] = v.Free
+		metrics["nr"] = v.NR
+		acc.AddFields("hugepages", metrics, tags)
+	}
+	return nil
+}
+
+// GatherHugepagesStatsFromMeminfo collects hugepages statistics from meminfo file
+func (mem *Hugepages) GatherStatsFromMeminfo(acc telegraf.Accumulator) error {
+	tags := map[string]string{
+		"name": "meminfo",
+	}
+	metrics := make(map[string]interface{})
+	meminfoMetrics, err := statsFromMeminfo(mem.MeminfoPath)
+	if err != nil {
+		return err
+	}
+
+	for k, v := range meminfoMetrics {
+		metrics[k] = v
+	}
+	acc.AddFields("hugepages", metrics, tags)
+	return nil
+}
+
+type HugepagesNUMAStats struct {
+	Free int
+	NR   int
+}
+
+// statsPerNUMA gathers hugepages statistics from each NUMA node
+func statsPerNUMA(path string) (map[string]HugepagesNUMAStats, error) {
+	var hugepagesStats = make(map[string]HugepagesNUMAStats)
+	dirs, err := ioutil.ReadDir(path)
+	if err != nil {
+		return hugepagesStats, err
+	}
+
+	for _, d := range dirs {
+		if !(d.IsDir() && strings.HasPrefix(d.Name(), "node")) {
+			continue
+		}
+
+		hugepagesFree := fmt.Sprintf("%s/%s/hugepages/hugepages-2048kB/free_hugepages", path, d.Name())
+		hugepagesNR := fmt.Sprintf("%s/%s/hugepages/hugepages-2048kB/nr_hugepages", path, d.Name())
+
+		free, err := ioutil.ReadFile(hugepagesFree)
+		if err != nil {
+			return hugepagesStats, err
+		}
+
+		nr, err := ioutil.ReadFile(hugepagesNR)
+		if err != nil {
+			return hugepagesStats, err
+		}
+
+		f, _ := strconv.Atoi(string(bytes.TrimSuffix(free, newlineByte)))
+		n, _ := strconv.Atoi(string(bytes.TrimSuffix(nr, newlineByte)))
+
+		hugepagesStats[d.Name()] = HugepagesNUMAStats{Free: f, NR: n}
+
+	}
+	return hugepagesStats, nil
+}
+
+// statsFromMeminfo gathers hugepages statistics from kernel
+func statsFromMeminfo(path string) (map[string]interface{}, error) {
+	stats := map[string]interface{}{}
+	meminfo, err := ioutil.ReadFile(path)
+	if err != nil {
+		return stats, err
+	}
+	lines := bytes.Split(meminfo, newlineByte)
+	for _, l := range lines {
+		if bytes.Contains(l, kbPrecisionByte) {
+			continue
+		}
+		fields := bytes.Fields(l)
+		if len(fields) < 2 {
+			continue
+		}
+		fieldName := string(bytes.TrimSuffix(fields[0], colonByte))
+		if fieldName == HUGE_PAGES_TOTAL || fieldName == HUGE_PAGES_FREE {
+			val, _ := strconv.Atoi(string(fields[1]))
+			stats[fieldName] = val
+		}
+	}
+	return stats, nil
+}
+
+// loadPaths can be used to read paths firstly from config
+// if it is empty then try read from env variables
+func (mem *Hugepages) loadPaths() {
+	if mem.NUMANodePath == "" {
+		mem.NUMANodePath = NUMA_NODE_PATH
+	}
+	if mem.MeminfoPath == "" {
+		mem.MeminfoPath = MEMINFO_PATH
+	}
+}
+
+func init() {
+	inputs.Add("hugepages", func() telegraf.Input {
+		return &Hugepages{}
+	})
+}

plugins/inputs/system/hugepages_test.go

@@ -0,0 +1,43 @@
+package system
+
+import (
+	"testing"
+
+	"github.com/influxdata/telegraf/testutil"
+)
+
+var hugepages = Hugepages{
+	NUMANodePath: "./testdata/node",
+	MeminfoPath:  "./testdata/meminfo",
+}
+
+func init() {
+	hugepages.loadPaths()
+}
+
+func TestHugepagesStatsFromMeminfo(t *testing.T) {
+	acc := &testutil.Accumulator{}
+	err := hugepages.GatherStatsFromMeminfo(acc)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fields := map[string]interface{}{
+		"HugePages_Total": int(666),
+		"HugePages_Free":  int(999),
+	}
+	acc.AssertContainsFields(t, "hugepages", fields)
+}
+
+func TestHugepagesStatsPerNode(t *testing.T) {
+	acc := &testutil.Accumulator{}
+	err := hugepages.GatherStatsPerNode(acc)
+	if err != nil {
+		t.Fatal(err)
+	}
+	fields := map[string]interface{}{
+		"free": int(123),
+		"nr":   int(456),
+	}
+	acc.AssertContainsFields(t, "hugepages", fields)
+}

plugins/inputs/system/testdata/meminfo

@@ -0,0 +1,45 @@
+MemTotal:        5961204 kB
+MemFree:         5201764 kB
+MemAvailable:    5761624 kB
+Buffers:          120248 kB
+Cached:           419660 kB
+SwapCached:            0 kB
+Active:           370656 kB
+Inactive:         247364 kB
+Active(anon):      79032 kB
+Inactive(anon):      552 kB
+Active(file):     291624 kB
+Inactive(file):   246812 kB
+Unevictable:           0 kB
+Mlocked:               0 kB
+SwapTotal:             0 kB
+SwapFree:              0 kB
+Dirty:                 4 kB
+Writeback:             0 kB
+AnonPages:         78164 kB
+Mapped:           114164 kB
+Shmem:              1452 kB
+Slab:              77180 kB
+SReclaimable:      57676 kB
+SUnreclaim:        19504 kB
+KernelStack:        2832 kB
+PageTables:         8692 kB
+NFS_Unstable:          0 kB
+Bounce:                0 kB
+WritebackTmp:          0 kB
+CommitLimit:     2980600 kB
+Committed_AS:     555492 kB
+VmallocTotal:   34359738367 kB
+VmallocUsed:           0 kB
+VmallocChunk:          0 kB
+HardwareCorrupted:     0 kB
+AnonHugePages:         0 kB
+CmaTotal:              0 kB
+CmaFree:               0 kB
+HugePages_Total:       666
+HugePages_Free:        999
+HugePages_Rsvd:        0
+HugePages_Surp:        0
+Hugepagesize:       2048 kB
+DirectMap4k:       84224 kB
+DirectMap2M:     6055936 kB

plugins/inputs/system/testdata/node/node0/hugepages/hugepages-2048kB/free_hugepages

@@ -0,0 +1 @@
+123

plugins/inputs/system/testdata/node/node0/hugepages/hugepages-2048kB/nr_hugepages

@@ -0,0 +1 @@
+456