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jsonファイルをinfluxdbのfieldsに保存する

1行ごとに値の入ったjsonファイルをinfluxdbのfieldsに保存するプログラムを書いた

influxdbはgolangで書かれているようなので、golangで実行プログラムを作成してみた

環境

  • go: 1.9.2
  • influxdb: 1.3.7

準備

go get

influxdbのクライアントライブラリをインストール

go get "github.com/influxdata/influxdb/client/v2"

jsonファイル

1行ごとに値の入ったjsonファイルを用意

cat test.json 
{"idle": 40.5, "system": 29.9, "user": 31.3}
{"idle": 56.8, "system":  7.7, "user": 47.9}
{"idle": 34.8, "system": 74.5, "user": 75.4}
{"idle": 15.7, "system":  2.3, "user": 41.9}
{"idle": 43.3, "system": 19.0, "user": 19.9}
{"idle":  9.9, "system": 96.7, "user": 86.5}
{"idle": 87.7, "system": 12.9, "user": 64.0}
{"idle":  4.3, "system": 55.1, "user": 80.3}
{"idle": 31.9, "system": 71.6, "user":  8.6}
{"idle": 48.7, "system": 49.1, "user": 86.6}

実装

main.go
package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"time"

	client "github.com/influxdata/influxdb/client/v2"
)

const (
	db       = "test"
    username = "bubba"
    password = "bumblebeetuna"
	meas     = "cpu_usage"
)

type Point struct {
	name   string
	tags   map[string]string
	fields map[string]interface{}
}

type Data struct {
	Idle   float64 `json:"idle"`
	System float64 `json:"system"`
	User   float64 `json:"user"`
}

func runQuery(c client.Client, cmd string) {
	q := client.NewQuery(cmd, db, "")
	if res, err := c.Query(q); err != nil && res.Error() == nil {
		fmt.Errorf("runQuery() error: %v: %s\n", res.Results, err)
	}
}

func writeData(c client.Client, p Point) {
	// Create a new point batch
	bp, err := client.NewBatchPoints(client.BatchPointsConfig{
		Database:  db,
		Precision: "",
	})
	if err != nil {
		log.Fatal(err)
	}

	pt, err := client.NewPoint(p.name, p.tags, p.fields, time.Now())
	if err != nil {
		log.Fatal(err)
	}
	bp.AddPoint(pt)

	// Write the batch
	if err := c.Write(bp); err != nil {
		log.Fatal(err)
	}
}

func fromFile(filePath string) []string {
	f, err := os.Open(filePath)
	if err != nil {
		fmt.Errorf("%s could not read: %v\n", filePath, err)
	}
	defer f.Close()

	// read each line by Scanner()
	lines := []string{}
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		lines = append(lines, scanner.Text())
	}
	if serr := scanner.Err(); serr != nil {
		fmt.Fprintf(os.Stderr, "%s scanner error: %v\n", filePath, err)
	}

	return lines
}

func main() {

	// Create a new HTTPClient
	c, err := client.NewHTTPClient(client.HTTPConfig{
		Addr:     "http://localhost:8086",
		Username: username,
		Password: password,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()

	// create database if not exists
	runQuery(c, fmt.Sprintf("CREATE DATABASE %s", db))

	// read json each line
	lines := fromFile("test.json")
	d := new(Data)

	for _, v := range lines {
		jsonBytes := ([]byte)(v)
		if err := json.Unmarshal(jsonBytes, d); err != nil {
			fmt.Errorf("JSON Unmarshal error: %s", err)
			return
		}

		// insert data
		p := Point{
			name: meas,
			tags: map[string]string{
				"cpu": "cpu-total",
			},
			fields: map[string]interface{}{
				"idle":   d.Idle,
				"system": d.System,
				"user":   d.User,
			},
		}
		writeData(c, p)
	}
}

確認

influxdb APIがhttp://localhost:8086で立ち上がっているとする

go run main.go
curl -G -XGET 'http://localhost:8086/query?pretty=true' --data-urlencode "db=test" --data-urlencode 'q=SELECT "idle","system","user" FROM cpu_usage'
{
    "results": [
        {
            "statement_id": 0,
            "series": [
                {
                    "name": "cpu_usage",
                    "columns": [
                        "time",
                        "idle",
                        "system",
                        "user"
                    ],
                    "values": [

                        [
                            "2017-11-26T07:59:46.984294Z",
                            40.5,
                            29.9,
                            31.3
                        ],
                        [
                            "2017-11-26T07:59:46.990029Z",
                            56.8,
                            7.7,
                            47.9
                        ],
                        [
                            "2017-11-26T07:59:46.991943Z",
                            34.8,
                            74.5,
                            75.4
                        ],
                        [
                            "2017-11-26T07:59:46.993493Z",
                            15.7,
                            2.3,
                            41.9
                        ],
                        [
                            "2017-11-26T07:59:46.994823Z",
                            43.3,
                            19,
                            19.9
                        ],
                        [
                            "2017-11-26T07:59:46.996119Z",
                            9.9,
                            96.7,
                            86.5
                        ],
                        [
                            "2017-11-26T07:59:46.997135Z",
                            87.7,
                            12.9,
                            64
                        ],
                        [
                            "2017-11-26T07:59:46.9983Z",
                            4.3,
                            55.1,
                            80.3
                        ],
                        [
                            "2017-11-26T07:59:46.999264Z",
                            31.9,
                            71.6,
                            8.6
                        ],
                        [
                            "2017-11-26T07:59:47.000413Z",
                            48.7,
                            49.1,
                            86.6
                        ]
                    ]
                }
            ]
        }
    ]
}

おまけ(jsonファイルの生成コマンド)

test.jsonの生成はシェルスクリプトを用いた

generate_json.sh
#!/bin/bash

#引数の数は1個
if [ $# -ne 1 ]; then
  echo "arguments are $# items" 1>&2
  echo "1 arguments(how many generate json row) required to execute" 1>&2
  exit 1
fi

# 引数で指定した行数だけ生成
for l in `seq $1`; do
  echo "{\"idle\": `awk 'BEGIN{ srand('"$RANDOM"'); printf("%2.1f", rand()*100) }'`, \
\"system\": `awk 'BEGIN{ srand('"$RANDOM"'); printf("%2.1f", rand()*100) }'`, \
\"user\": `awk 'BEGIN{ srand('"$RANDOM"'); printf("%2.1f", rand()*100) }'`\
}"
done

jsonファイルの生成

chmod +x generate_json.sh
./generate_json.sh 10 > test.json
cat test.json 
{"idle": 40.5, "system": 29.9, "user": 31.3}
{"idle": 56.8, "system":  7.7, "user": 47.9}
{"idle": 34.8, "system": 74.5, "user": 75.4}
{"idle": 15.7, "system":  2.3, "user": 41.9}
{"idle": 43.3, "system": 19.0, "user": 19.9}
{"idle":  9.9, "system": 96.7, "user": 86.5}
{"idle": 87.7, "system": 12.9, "user": 64.0}
{"idle":  4.3, "system": 55.1, "user": 80.3}
{"idle": 31.9, "system": 71.6, "user":  8.6}
{"idle": 48.7, "system": 49.1, "user": 86.6}

参考

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