Add cgroup plugin

plugins/inputs/all/all.go

@@ -6,6 +6,7 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/inputs/bcache"
 	_ "github.com/influxdata/telegraf/plugins/inputs/cassandra"
 	_ "github.com/influxdata/telegraf/plugins/inputs/ceph"
+	_ "github.com/influxdata/telegraf/plugins/inputs/cgroup"
 	_ "github.com/influxdata/telegraf/plugins/inputs/chrony"
 	_ "github.com/influxdata/telegraf/plugins/inputs/cloudwatch"
 	_ "github.com/influxdata/telegraf/plugins/inputs/conntrack"

plugins/inputs/cgroup/README.md

@@ -0,0 +1,58 @@
+# CGroup Input Plugin For Telegraf Agent
+
+This input plugin will capture specific statistics per cgroup.
+
+Following file formats are supported:
+
+* Single value
+
+```
+VAL\n
+```
+
+* New line separated values
+
+```
+VAL0\n
+VAL1\n
+```
+
+* Space separated values
+
+```
+VAL0 VAL1 ...\n
+```
+
+* New line separated key-space-value's
+
+```
+KEY0 VAL0\n
+KEY1 VAL1\n
+```
+
+
+### Tags:
+
+All measurements have the following tags:
+  - path
+
+
+### Configuration:
+
+```
+# [[inputs.cgroup]]
+  # paths = [
+  #   "/cgroup/memory",           # root cgroup
+  #   "/cgroup/memory/child1",    # container cgroup
+  #   "/cgroup/memory/child2/*",  # all children cgroups under child2, but not child2 itself
+  # ]
+  # fields = ["memory.*usage*", "memory.limit_in_bytes"]
+
+# [[inputs.cgroup]]
+  # paths = [
+  #   "/cgroup/cpu",              # root cgroup
+  #   "/cgroup/cpu/*",            # all container cgroups
+  #   "/cgroup/cpu/*/*",          # all children cgroups under each container cgroup
+  # ]
+  # fields = ["cpuacct.usage", "cpu.cfs_period_us", "cpu.cfs_quota_us"]
+```

plugins/inputs/cgroup/cgroup.go

@@ -0,0 +1,271 @@
+// +build linux
+
+package cgroup
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"strconv"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+const metricName = "cgroup"
+
+type CGroup struct {
+	Paths []string `toml:"paths"`
+	Files []string `toml:"fields"`
+}
+
+var sampleConfig = `
+	# paths = [
+	#   "/cgroup/memory",
+	#   "/cgroup/memory/child1",
+	#   "/cgroup/memory/child2/*",
+	# ]
+	# fields = ["memory.*usage*", "memory.limit_in_bytes"]
+`
+
+func (g *CGroup) SampleConfig() string {
+	return sampleConfig
+}
+
+func (g *CGroup) Description() string {
+	return "Read specific statistics per cgroup"
+}
+
+func (g *CGroup) Gather(acc telegraf.Accumulator) error {
+	list := make(chan pathInfo)
+	go g.generateDirs(list)
+
+	for dir := range list {
+		if dir.err != nil {
+			return dir.err
+		}
+		if err := g.gatherDir(dir.path, acc); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (g *CGroup) gatherDir(dir string, acc telegraf.Accumulator) error {
+	fields := make(map[string]interface{})
+
+	list := make(chan pathInfo)
+	go g.generateFiles(dir, list)
+
+	for file := range list {
+		if file.err != nil {
+			return file.err
+		}
+
+		raw, err := ioutil.ReadFile(file.path)
+		if err != nil {
+			return err
+		}
+		if len(raw) == 0 {
+			continue
+		}
+
+		fd := fileData{data: raw, path: file.path}
+		if err := fd.parse(fields); err != nil {
+			return err
+		}
+	}
+
+	tags := map[string]string{"path": dir}
+
+	acc.AddFields(metricName, fields, tags)
+
+	return nil
+}
+
+// ======================================================================
+
+type pathInfo struct {
+	path string
+	err  error
+}
+
+func isDir(path string) (bool, error) {
+	result, err := os.Stat(path)
+	if err != nil {
+		return false, err
+	}
+	return result.IsDir(), nil
+}
+
+func (g *CGroup) generateDirs(list chan<- pathInfo) {
+	for _, dir := range g.Paths {
+		// getting all dirs that match the pattern 'dir'
+		items, err := filepath.Glob(dir)
+		if err != nil {
+			list <- pathInfo{err: err}
+			return
+		}
+
+		for _, item := range items {
+			ok, err := isDir(item)
+			if err != nil {
+				list <- pathInfo{err: err}
+				return
+			}
+			// supply only dirs
+			if ok {
+				list <- pathInfo{path: item}
+			}
+		}
+	}
+	close(list)
+}
+
+func (g *CGroup) generateFiles(dir string, list chan<- pathInfo) {
+	for _, file := range g.Files {
+		// getting all file paths that match the pattern 'dir + file'
+		// path.Base make sure that file variable does not contains part of path
+		items, err := filepath.Glob(path.Join(dir, path.Base(file)))
+		if err != nil {
+			list <- pathInfo{err: err}
+			return
+		}
+
+		for _, item := range items {
+			ok, err := isDir(item)
+			if err != nil {
+				list <- pathInfo{err: err}
+				return
+			}
+			// supply only files not dirs
+			if !ok {
+				list <- pathInfo{path: item}
+			}
+		}
+	}
+	close(list)
+}
+
+// ======================================================================
+
+type fileData struct {
+	data []byte
+	path string
+}
+
+func (fd *fileData) format() (*fileFormat, error) {
+	for _, ff := range fileFormats {
+		ok, err := ff.match(fd.data)
+		if err != nil {
+			return nil, err
+		}
+		if ok {
+			return &ff, nil
+		}
+	}
+
+	return nil, fmt.Errorf("%v: unknown file format", fd.path)
+}
+
+func (fd *fileData) parse(fields map[string]interface{}) error {
+	format, err := fd.format()
+	if err != nil {
+		return err
+	}
+
+	format.parser(filepath.Base(fd.path), fields, fd.data)
+	return nil
+}
+
+// ======================================================================
+
+type fileFormat struct {
+	name    string
+	pattern string
+	parser  func(measurement string, fields map[string]interface{}, b []byte)
+}
+
+const keyPattern = "[[:alpha:]_]+"
+const valuePattern = "[\\d-]+"
+
+var fileFormats = [...]fileFormat{
+	// 	VAL\n
+	fileFormat{
+		name:    "Single value",
+		pattern: "^" + valuePattern + "\n$",
+		parser: func(measurement string, fields map[string]interface{}, b []byte) {
+			re := regexp.MustCompile("^(" + valuePattern + ")\n$")
+			matches := re.FindAllStringSubmatch(string(b), -1)
+			fields[measurement] = numberOrString(matches[0][1])
+		},
+	},
+	// 	VAL0\n
+	// 	VAL1\n
+	// 	...
+	fileFormat{
+		name:    "New line separated values",
+		pattern: "^(" + valuePattern + "\n){2,}$",
+		parser: func(measurement string, fields map[string]interface{}, b []byte) {
+			re := regexp.MustCompile("(" + valuePattern + ")\n")
+			matches := re.FindAllStringSubmatch(string(b), -1)
+			for i, v := range matches {
+				fields[measurement+"."+strconv.Itoa(i)] = numberOrString(v[1])
+			}
+		},
+	},
+	// 	VAL0 VAL1 ...\n
+	fileFormat{
+		name:    "Space separated values",
+		pattern: "^(" + valuePattern + " )+\n$",
+		parser: func(measurement string, fields map[string]interface{}, b []byte) {
+			re := regexp.MustCompile("(" + valuePattern + ") ")
+			matches := re.FindAllStringSubmatch(string(b), -1)
+			for i, v := range matches {
+				fields[measurement+"."+strconv.Itoa(i)] = numberOrString(v[1])
+			}
+		},
+	},
+	// 	KEY0 VAL0\n
+	// 	KEY1 VAL1\n
+	// 	...
+	fileFormat{
+		name:    "New line separated key-space-value's",
+		pattern: "^(" + keyPattern + " " + valuePattern + "\n)+$",
+		parser: func(measurement string, fields map[string]interface{}, b []byte) {
+			re := regexp.MustCompile("(" + keyPattern + ") (" + valuePattern + ")\n")
+			matches := re.FindAllStringSubmatch(string(b), -1)
+			for _, v := range matches {
+				fields[measurement+"."+v[1]] = numberOrString(v[2])
+			}
+		},
+	},
+}
+
+func numberOrString(s string) interface{} {
+	i, err := strconv.Atoi(s)
+	if err == nil {
+		return i
+	}
+
+	return s
+}
+
+func (f fileFormat) match(b []byte) (bool, error) {
+	ok, err := regexp.Match(f.pattern, b)
+	if err != nil {
+		return false, err
+	}
+	if ok {
+		return true, nil
+	}
+	return false, nil
+}
+
+func init() {
+	inputs.Add("cgroup", func() telegraf.Input { return &CGroup{} })
+}

plugins/inputs/cgroup/cgroup_notlinux.go

@@ -0,0 +1,3 @@
+// +build !linux
+
+package cgroup