prometheus api调用

库

	"github.com/prometheus/client_golang/api"
	Pro "github.com/prometheus/client_golang/api/prometheus/v1"

获取平台已部署的prometheus的client

var systemPublicEndpoint api.Client

//连接prometheus,无多集群管理时无需传入集群ID
func ConnectPro(clusterID string) api.Client {
	ns := "System"     //部署在哪个命名空间
	name := "prometheus:prometheus-server"    //prometheus-server 组件地址（对应k8s集群中prometheus应用组件的id）
	if nil != systemPublicEndpoint {
		return systemPublicEndpoint
	}
	cli, _ := utils.GetPrometheusPublicCli(clusterID, ns, name)
	systemPublicEndpoint = cli
	return cli
}


func GetPrometheusPublicCli(clusterID, namespace, name string) (api.Client, error) {
    //省略获取普罗米修斯server暴露的访问地址逻辑，获取地址addr后组成Config传入
        cfg := api.Config{Address: "http://" + addr}    //地址示例：http://192.168.104.65:30870
	c, err := api.NewClient(cfg)
	return c, err
}

以节点cpu的平均使用率为例调api查询：

    c1 := ConnectPro(s.Get(consts.KeyCluster).(string))
        //mon.Start与mon.End为起始、终止时间，mon为前端传入的对象
	sta, _ := strconv.Atoi(mon.Start)
	en, _ := strconv.Atoi(mon.End)
	rat := en - sta
	rat = rat + 60
	if rat < 120 {
		rat = 120
	}
    //分子/分母=比率，mon.Node为节点名称
	q1 := "sum(rate (container_cpu_usage_seconds_total{id='/',kubernetes_io_hostname=~'" + mon.Node + "$'" + "}[" + strconv.Itoa(rat) + "s]))"
	q2 := "/sum (machine_cpu_cores{kubernetes_io_hostname=~'" + mon.Node + "$'})*100"
	q := q1 + q2
	c, err := pro.NewAPI(c1).Query(context.Background(), q, mon.End)
	if err != nil {
		errMsg := fmt.Sprint("failed to Query NodeCpuRate:", err.Error())
		logError(errMsg)
		ctx.Resp.Header().Set(consts.KeyErrorInfo, errMsg)
		return macaron.ReturnStruct{Code: http.StatusBadRequest, Msg: errMsg}
	}
	return macaron.ReturnStruct{Data: c}

查询返回：

{"message":"","code":200,"data":[{"metric":{},"value":[1572431847,"15.910989253603638"]}]}

即15.9%