Improve docker input plugin

plugins/inputs/docker/README.md

@@ -95,25 +95,67 @@ on the availability of per-cpu stats on your system.
     - io_serviced_recursive_sync
     - io_serviced_recursive_total
     - io_serviced_recursive_write
+- docker_
+    - n_used_file_descriptors
+    - n_cpus
+    - n_containers
+    - n_images
+    - n_goroutines
+    - n_listener_events
+    - memory_total
+    - pool_blocksize
+- docker_data
+    - available
+    - total
+    - used
+- docker_metadata
+    - available
+    - total
+    - used
+
 
 ### Tags:
 
-- All stats have the following tags:
+- docker (memory_total)
+    - unit=bytes
+- docker (pool_blocksize)
+    - unit=bytes
+- docker_data
+    - unit=bytes
+- docker_metadata
+    - unit=bytes
+
+- docker_cpu specific:
     - cont_id (container ID)
     - cont_image (container image)
     - cont_name (container name)
-- docker_cpu specific:
     - cpu
 - docker_net specific:
+    - cont_id (container ID)
+    - cont_image (container image)
+    - cont_name (container name)
     - network
 - docker_blkio specific:
+    - cont_id (container ID)
+    - cont_image (container image)
+    - cont_name (container name)
     - device
 
 ### Example Output:
 
 ```
 % ./telegraf -config ~/ws/telegraf.conf -input-filter docker -test
 * Plugin: docker, Collection 1
+> docker n_cpus=8i 1456926671065383978
+> docker n_used_file_descriptors=15i 1456926671065383978
+> docker n_containers=7i 1456926671065383978
+> docker n_images=152i 1456926671065383978
+> docker n_goroutines=36i 1456926671065383978
+> docker n_listener_events=0i 1456926671065383978
+> docker,unit=bytes memory_total=18935443456i 1456926671065383978
+> docker,unit=bytes pool_blocksize=65540i 1456926671065383978
+> docker_data,unit=bytes available=24340000000i,total=107400000000i,used=14820000000i 1456926671065383978
+> docker_metadata,unit=bytes available=2126999999i,total=2146999999i,used=20420000i 145692667106538
 > docker_mem,cont_id=5705ba8ed8fb47527410653d60a8bb2f3af5e62372297c419022a3cc6d45d848,\
 cont_image=spotify/kafka,cont_name=kafka \
 active_anon=52568064i,active_file=6926336i,cache=12038144i,fail_count=0i,\

plugins/inputs/docker/docker.go

@@ -1,8 +1,11 @@
 package system
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
+	"regexp"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -17,9 +20,29 @@ type Docker struct {
 	Endpoint       string
 	ContainerNames []string
 
-	client *docker.Client
+	client DockerClient
 }
 
+type DockerClient interface {
+	// Docker Client wrapper
+	// Useful for test
+	Info() (*docker.Env, error)
+	ListContainers(opts docker.ListContainersOptions) ([]docker.APIContainers, error)
+	Stats(opts docker.StatsOptions) error
+}
+
+const (
+	KB = 1000
+	MB = 1000 * KB
+	GB = 1000 * MB
+	TB = 1000 * GB
+	PB = 1000 * TB
+)
+
+var (
+	sizeRegex = regexp.MustCompile(`^(\d+(\.\d+)*) ?([kKmMgGtTpP])?[bB]?$`)
+)
+
 var sampleConfig = `
   ## Docker Endpoint
   ##   To use TCP, set endpoint = "tcp://[ip]:[port]"
@@ -58,12 +81,20 @@ func (d *Docker) Gather(acc telegraf.Accumulator) error {
 		d.client = c
 	}
 
+	// Get daemon info
+	err := d.gatherInfo(acc)
+	if err != nil {
+		fmt.Println(err.Error())
+	}
+
+	// List containers
 	opts := docker.ListContainersOptions{}
 	containers, err := d.client.ListContainers(opts)
 	if err != nil {
 		return err
 	}
 
+	// Get container data
 	var wg sync.WaitGroup
 	wg.Add(len(containers))
 	for _, container := range containers {
@@ -81,6 +112,76 @@ func (d *Docker) Gather(acc telegraf.Accumulator) error {
 	return nil
 }
 
+func (d *Docker) gatherInfo(acc telegraf.Accumulator) error {
+	// Init vars
+	var driverStatus [][]string
+	dataFields := make(map[string]interface{})
+	metadataFields := make(map[string]interface{})
+	now := time.Now()
+	// Get info from docker daemon
+	info, err := d.client.Info()
+	if err != nil {
+		return err
+	}
+
+	fields := map[string]interface{}{
+		"n_cpus":                  info.GetInt64("NCPU"),
+		"n_used_file_descriptors": info.GetInt64("NFd"),
+		"n_containers":            info.GetInt64("Containers"),
+		"n_images":                info.GetInt64("Images"),
+		"n_goroutines":            info.GetInt64("NGoroutines"),
+		"n_listener_events":       info.GetInt64("NEventsListener"),
+	}
+	// Add metrics
+	acc.AddFields("docker",
+		fields,
+		nil,
+		now)
+	acc.AddFields("docker",
+		map[string]interface{}{"memory_total": info.GetInt64("MemTotal")},
+		map[string]string{"unit": "bytes"},
+		now)
+	// Get storage metrics
+	driverStatusRaw := []byte(info.Get("DriverStatus"))
+	json.Unmarshal(driverStatusRaw, &driverStatus)
+	for _, rawData := range driverStatus {
+		// Try to convert string to int (bytes)
+		value, err := parseSize(rawData[1])
+		if err != nil {
+			continue
+		}
+		name := strings.ToLower(strings.Replace(rawData[0], " ", "_", -1))
+		if name == "pool_blocksize" {
+			// pool blocksize
+			acc.AddFields("docker",
+				map[string]interface{}{"pool_blocksize": value},
+				map[string]string{"unit": "bytes"},
+				now)
+		} else if strings.HasPrefix(name, "data_space_") {
+			// data space
+			field_name := strings.TrimPrefix(name, "data_space_")
+			dataFields[field_name] = value
+		} else if strings.HasPrefix(name, "metadata_space_") {
+			// metadata space
+			field_name := strings.TrimPrefix(name, "metadata_space_")
+			metadataFields[field_name] = value
+		}
+	}
+	if len(dataFields) > 0 {
+		acc.AddFields("docker_data",
+			dataFields,
+			map[string]string{"unit": "bytes"},
+			now)
+	}
+	if len(metadataFields) > 0 {
+		acc.AddFields("docker_metadata",
+			metadataFields,
+			map[string]string{"unit": "bytes"},
+			now)
+	}
+	return nil
+}
+
 func (d *Docker) gatherContainer(
 	container docker.APIContainers,
 	acc telegraf.Accumulator,
@@ -334,6 +435,27 @@ func sliceContains(in string, sl []string) bool {
 	return false
 }
 
+// Parses the human-readable size string into the amount it represents.
+func parseSize(sizeStr string) (int64, error) {
+	matches := sizeRegex.FindStringSubmatch(sizeStr)
+	if len(matches) != 4 {
+		return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
+	}
+
+	size, err := strconv.ParseFloat(matches[1], 64)
+	if err != nil {
+		return -1, err
+	}
+
+	uMap := map[string]int64{"k": KB, "m": MB, "g": GB, "t": TB, "p": PB}
+	unitPrefix := strings.ToLower(matches[3])
+	if mul, ok := uMap[unitPrefix]; ok {
+		size *= float64(mul)
+	}
+
+	return int64(size), nil
+}
+
 func init() {
 	inputs.Add("docker", func() telegraf.Input {
 		return &Docker{}