go接收alertmanager告警并发送钉钉

前言

• 功能：作为 alertmanager 的 webhook receiver，提取需要的数据转发到钉钉群机器人的webhook
• web框架：gin
• alertmanager版本：0.24
• 系统版本：ubuntu 20.04
• 功能比较简单，所以就随便写了，全部属于main包

原始json数据示例

{
    "receiver": "web\\.hook",
    "status": "firing",
    "alerts": [{
        "status": "firing",
        "labels": {
            "alertname": "node",
            "instance": "192.168.0.10",
            "job": "rh7",
            "severity": "critical"
        },
        "annotations": {
            "description": "rh7 192.168.0.10 节点断联已超过1分钟！",
            "summary": "192.168.0.10 down "
        },
        "startsAt": "2022-04-28T08:44:23.05Z",
        "endsAt": "0001-01-01T00:00:00Z",
        "generatorURL": "http://localhost.localdomain:19090/graph?g0.expr=up+%3D%3D+0\u0026g0.tab=1",
        "fingerprint": "726681bf4674e8a5"
    }],
    "groupLabels": {
        "alertname": "node"
    },
    "commonLabels": {
        "alertname": "node",
        "instance": "192.168.0.10",
        "job": "rh7",
        "severity": "critical"
    },
    "commonAnnotations": {
        "description": "rh7 192.168.0.10 节点断联已超过1分钟！",
        "summary": "192.168.0.10 down "
    },
    "externalURL": "http://192.168.0.10:19092",
    "version": "4",
    "groupKey": "{}:{alertname=\"node\"}",
    "truncatedAlerts": 0
}

示例代码

• model.go（定义结构体）

package main

// 定义接收JSON数据的结构体
type ReqAlert struct {
	Status       string              `json:"status"`
	StartsAt     string              `json:"startsAt"`
	EndsAt       string              `json:"endsAt"`
	GeneratorURL string              `json:"generatorURL"`
	Fingerprint  string              `json:"fingerprint"`
	Labels       ReqAlertLabel       `json:"labels"`
	Annotations  ReqAlertAnnotations `json:"annotations"`
}

type ReqGroupLabels struct {
	Alertname string `json:"alertname"`
}

type ReqCommonLabels struct {
	Alertname string `json:"alertname"`
	Instance  string `json:"instance"`
	Job       string `json:"job"`
	Severity  string `json:"severity"`
}

type ReqCommonAnnotations struct {
	Description string `json:"description"`
	Summary     string `json:"summary"`
}

type ReqAlertLabel struct {
	Alertname string `json:"alertname"`
	Instance  string `json:"instance"`
	Job       string `json:"job"`
	Severity  string `json:"severity"`
}

type ReqAlertAnnotations struct {
	Description string `json:"description"`
	Summary     string `json:"summary"`
}

type RequestBody struct {
	// alertmanager传来的请求体
	Receiver          string               `json:"receiver"`
	Status            string               `json:"status"`
	ExternalURL       string               `json:"externalURL"`
	Version           string               `json:"version"`
	GroupKey          string               `json:"groupkey"`
	TruncatedAlerts   float64              `json:"truncatedAlerts"`
	Alert             []ReqAlert           `json:"alerts"`
	GroupLabels       ReqGroupLabels       `json:"groupLabels"`
	CommonLabels      ReqCommonLabels      `json:"commonLabels"`
	CommonAnnotations ReqCommonAnnotations `json:"commonAnnotations"`
}

• dingmsg.go（对接钉钉webhook，注意替换webhook的url）

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strings"
)

type Md struct {
	Title string `json:"title"`
	Text  string `json:"text"`
}

type Ding struct {
	Msgtype  string `json:"msgtype"`
	Markdown Md     `json:"markdown"`
}

func DingMarshal(text string) string {
	// struct序列化为json
	var myjson Ding = Ding{
		Msgtype: "markdown",
		Markdown: Md{
			Title: "锄田测试钉钉机器人",
			Text:  text,
		},
	}
	va, err := json.Marshal(myjson)
	if err != nil {
		panic(err)
	}
	return string(va)
}

func PostUrl(jsondata string) {
	// 发起post请求
	// 替换钉钉群机器人的webhook
	url := "https://oapi.dingtalk.com/robot/send?access_token=123456"
	var jsonstr = []byte(jsondata)
	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonstr))
	if err != nil {
		log.Fatal(err)
	}

	req.Header.Set("Content-Type", "application/json;charset=utf-8")
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("钉钉webhook响应: %v\n", string(body))
}

func SpliceString(status, description, summary string) string {
	// 拼接字符串
	var rst strings.Builder
	rst.WriteString("# 锄田测试钉钉机器人 \n\n")
	rst.WriteString("- status: " + status + " \n\n")
	rst.WriteString("- description: " + description + " \n\n")
	rst.WriteString("- summary: " + summary + " \n\n")
	return rst.String()
}

• main.go

package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/gin-gonic/gin"
)

func ParseJson(c *gin.Context) {
	// 解析AlertManager 传递的 json 数据
	var json RequestBody
	// 将数据解析到结构体中
	if err := c.ShouldBindJSON(&json); err != nil {
		// 返回错误信息
		c.JSON(http.StatusBadRequest, gin.H{
			"error": err.Error(),
		})
		return
	}

	// 遍历json中alerts数据
	for k, v := range json.Alert {
		fmt.Printf("k: %d, status: %s, description: %s, summary: %s \n", k, v.Status, v.Annotations.Description, v.Annotations.Summary)
		text := SpliceString(v.Status, v.Annotations.Description, v.Annotations.Summary)
		va := DingMarshal(text)
		PostUrl(va)
	}

	// 返回给客户端的消息
	c.JSON(http.StatusOK, gin.H{
		"msg": "success",
	})
}

func main() {
	// 设置gin运行模式，可选：DebugMode、ReleaseMode、TestMode
	gin.SetMode(gin.ReleaseMode)

	// 关闭控制台日志颜色
	gin.DisableConsoleColor()

	// 记录到文件
	f, _ := os.OpenFile("gin.log", os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0644)
	gin.DefaultWriter = io.MultiWriter(f)

	r := gin.Default()
	// 只接受来自127.0.0.1的请求
	r.SetTrustedProxies([]string{"127.0.0.1"})

	v1 := r.Group("/v1")
	{
		v1.POST("/alert", ParseJson)
	}

	// 设置程序优雅退出
	srv := &http.Server{
		Addr:    "127.0.0.1:19100",
		Handler: r,
	}

	go func() {
		if err := srv.ListenAndServe(); err != nil && errors.Is(err, http.ErrServerClosed) {
			log.Printf("listen: %s\n", err)
		}
	}()

	quit := make(chan os.Signal)
	signal.Notify(quit, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	log.Println("Shutting down server...")
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := srv.Shutdown(ctx); err != nil {
		log.Fatal("Server forced to shutdown:", err)
	}

	log.Println("Server exiting")
}

使用示例

1. 导入依赖

go mod tidy

1. 编译

go build -o goalert.bin ./main.go ./model.go ./dingmsg.go

1. 运行

./goalert.bin

1. 测试。使用python + requests 测试。python代码如下

import requests

# 注意json字符串的代码转为utf-8，否则会报Unicode的错误
# 使用json原字符串，而不是字典
json_firing = r"""
{"receiver":"web\\.hook","status":"firing","alerts":[{"status":"firing","labels":{"alertname":"node","instance":"192.168.0.10","job":"rh7","severity":"critical"},"annotations":{"description":"rh7 192.168.0.10 节点断联已超过1分钟！","summary":"192.168.0.10 down "},"startsAt":"2022-04-28T08:44:23.05Z","endsAt":"0001-01-01T00:00:00Z","generatorURL":"http://localhost.localdomain:19090/graph?g0.expr=up+%3D%3D+0\u0026g0.tab=1","fingerprint":"726681bf4674e8a5"}],"groupLabels":{"alertname":"node"},"commonLabels":{"alertname":"node","instance":"192.168.0.10","job":"rh7","severity":"critical"},"commonAnnotations":{"description":"rh7 192.168.0.10 节点断联已超过1分钟！","summary":"192.168.0.10 down "},"externalURL":"http://192.168.0.10:19092","version":"4","groupKey":"{}:{alertname=\"node\"}","truncatedAlerts":0}
""".encode("utf-8").decode("latin1")

url = "http://127.0.0.1:19100/v1/alert"

resp = requests.post(url=url, data = json_firing, headers={"Content-Type": "application/json"})

print(resp.text)

1. alertmanager配置略过

补充

• 钉钉可以通过面对面建群的方式建一个单人群，单人群也能添加机器人。
• 如果不知道alertmanager发送的json数据是什么样，可以写个服务端，直接接收数据不解析，在控制台原样输出字符串。示例代码如下：

package main

import (
	"fmt"
	"io/ioutil"
	"net/http"
)

func f1(w http.ResponseWriter, r *http.Request) {
	// 向客户端响应ok
	defer fmt.Fprintf(w, "ok\n")

	// 获取客户端的请求方式
	fmt.Println("method:", r.Method)
	// 获取客户端请求的body
	body, err := ioutil.ReadAll(r.Body)
	if err != nil {
		fmt.Printf("read body err, %v\n", err)
		return
	}
	fmt.Println("json: ", string(body))
}

func main() {
	http.HandleFunc("/", f1)
	http.ListenAndServe("127.0.0.1:8888", nil)
}