时序数据库influxDB（二）Go语言连接TSDB——influxDB2

1. 创建测试用的数据库

IP:8086

2. 下载 influxdb-client-go

go get github.com/influxdata/influxdb-client-go

3 编写代码

连接TSDB&&插入point

package main

import (
	"fmt"
	"time"

	influxdb2 "github.com/influxdata/influxdb-client-go/v2"
)

func main() {

	tsdb := influxdb2.NewClient("http://IP:8086",
		"UD3qST2Zu57fMZVmxaFTIxAhp6XA_CXt7YuUyQouyYfoAJtpAkH_CzmHP6BBLGY-XDAJVCthTClSLz0j2eg_Cg==")
	// get non-blocking write client
	writeAPI := tsdb.WriteAPI("xuehu96", "test")

	// 第一种写入方法
	writeAPI.WriteRecord(fmt.Sprintf("MEASUREMENT,unit=temperature avg=%f,max=%f", 4.5, 5.5))
	writeAPI.Flush()

	// 第二种写入方法
	p1 := influxdb2.NewPoint("MEASUREMENT",
		map[string]string{"unit": "temperature"},
		map[string]interface{}{"avg": 24.5, "max": 45.1},
		time.Now())
	writeAPI.WritePoint(p1)
	writeAPI.Flush()

	// 第三种写入方法 (这种好用)
	p := influxdb2.NewPointWithMeasurement("MEASUREMENT").
		AddTag("unit", "precent").
		AddField("avg", 23.2).
		AddField("max", 88.8).
		SetTime(time.Now())
	writeAPI.WritePoint(p)
	writeAPI.Flush()

	// TODO:在这里写查询代码

	defer tsdb.Close()
}

其中，第三种写入方法比较好，保留第三种写入方法，前两种注释掉
接下来是数据查询（在上一段代码 //TODO处写以下代码）

// 查询
	queryAPI := tsdb.QueryAPI("xuehu96")

	// Flux查询语句 相当于sql语句
	query := `from(bucket: "test")
	|> range(start: -1h)
	|> filter(fn: (r) => r["_measurement"] == "TestData")
	|> filter(fn: (r) => r["_field"] == "max" or r["_field"] == "avg")
	`

	// 查询结果
	result, err := queryAPI.Query(context.Background(), query)
	if err != nil {
		log.Fatalln(err.Error())
	}

	// 解析结果
	for result.Next() {
		//  类型 :    string,   float64,  string,  time.Time
		log.Printf("field: %v, value :%v, unit:%v, time:%v\n", result.Record().Field(), result.Record().Value(), result.Record().ValueByKey("unit"), result.Record().Time())
		/* 打印结果
			2022/04/08 11:11:44 field: avg, value :99.9, unit:precent, time:2022-04-08 03:11:37.4553546 +0000 UTC
			2022/04/08 11:11:44 field: avg, value :66.9, unit:precent, time:2022-04-08 03:11:44.7049963 +0000 UTC
			2022/04/08 11:11:44 field: max, value :40.8, unit:precent, time:2022-04-08 03:11:37.4553546 +0000 UTC
			2022/04/08 11:11:44 field: max, value :55.8, unit:precent, time:2022-04-08 03:11:44.7049963 +0000 UTC
		 */
	}
	if result.Err() != nil {
		log.Printf("query parsing error: %s \n", result.Err().Error())
	}

4. 效果