main.go

package main

import (
	// "fmt"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/urfave/cli/v2"
	"gopkg.in/yaml.v2"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"time"
)

const magicOffset = 34

var (
	powerData = promauto.NewGaugeVec(prometheus.GaugeOpts{
		Namespace: "ZJUSCT",
		Name:      "pdu_processed_power",
		Help:      "node power consumption",
	},
		[]string{
			"node",
			"place",
		})
	config conf
)

type conf struct {
	Url   string
	Interval int
	Nodes []struct {
		Name  string `yaml:"name"`
		Place []int  `yaml:",flow"`
	}
}

func parseYamlConfig(filename string) conf {
	yamlFile, err := ioutil.ReadFile(filename)
	if err != nil {
		log.Printf("yamlFile.Get err   #%v ", err)
	}

	c := conf{}
	err = yaml.Unmarshal(yamlFile, &c)
	if err != nil {
		log.Fatalf("error: %v", err)
	}

	return c
}

func recordMetrics() {
	go func() {
		for {
			resp, err := http.Get(config.Url)
			if err != nil {
				log.Fatalln(err)
			}
			body, err := ioutil.ReadAll(resp.Body)
			if err != nil {
				log.Fatalln(err)
			}
			sb := string(body)
			s := strings.Split(sb, "?")

			for _, node := range config.Nodes {
				//fmt.Printf("%s %d\n", node.Name, node.Place)
				for _, place := range node.Place {
					//fmt.Printf("%d\n", place)
					power, _ := strconv.Atoi(s[magicOffset + (place - 1) * 7])
					powerData.WithLabelValues(node.Name, strconv.Itoa(place)).Set(float64(power) / 1000)
				}
			}
			time.Sleep(time.Duration(config.Interval) * time.Second)
		}
	}()
}

func main() {
	app := &cli.App{
		Name:  "PDU Data Exporter",
		Usage: "PDU power exporter for prometheus",
		Flags: []cli.Flag{
			&cli.StringFlag{
				Name:     "config",
				Aliases:  []string{"c"},
				Usage:    "Load configuration from `FILE`",
				Value:    "config.yaml",
				EnvVars:  []string{"PDU_CONFIG_FILE"},
			},
			&cli.StringFlag{
				Name:     "listen",
				Aliases:  []string{"l"},
				Usage:    "Listen at `ADDRESS`",
				Value:    ":2112",
				EnvVars:  []string{"PDU_LISTEN_ADDRESS"},
			},
		},
		Action: func(c *cli.Context) error {
			config = parseYamlConfig(c.String("config"))
			log.Println("config: %v\n", config)

			recordMetrics()
			http.Handle("/metrics", promhttp.Handler())
			return http.ListenAndServe(c.String("listen"), nil)
		},
	}

	err := app.Run(os.Args)
	if err != nil {
		log.Fatal(err)
	}
}