From 8cc35a7b4472fcc05c39bf8aa5e5898e159d623c Mon Sep 17 00:00:00 2001
From: Jonathan Toledo <kry0ster@gmail.com>
Date: Wed, 2 Oct 2019 14:28:14 -0500
Subject: [PATCH] Telegram Notifications

---
 Config.md                 |  11 ++++
 README.md                 |   1 +
 notify/notify.go          |   1 +
 notify/telegram_notify.go | 109 ++++++++++++++++++++++++++++++++++++++
 sample_config.json        |   4 ++
 5 files changed, 126 insertions(+)
 create mode 100644 notify/telegram_notify.go

diff --git a/Config.md b/Config.md
index 6c536fa..d013357 100644
--- a/Config.md
+++ b/Config.md
@@ -186,6 +186,17 @@ To recieve notifications to any Dingding add below block to your config file wit
             "Content-Type":"application/json"
         }
 }
+```
+### Telegram
+
+To recieve notifications to your Telegram Channel/Chat, add below block to your config file with your telegram details
+
+```
+"telegram":{
+	"botToken":"bot token",
+	"chatID":"chat id"
+}
+
 ```
 [Dingding Dev Document](https://open-doc.dingtalk.com/docs/doc.htm?spm=a219a.7629140.0.0.Tvbh61&treeId=257&articleId=105735&docType=1)
 
diff --git a/README.md b/README.md
index 9298419..91324e2 100644
--- a/README.md
+++ b/README.md
@@ -127,6 +127,7 @@ Notifications will be triggered when mean response time is below given response
 3. [Mailgun](https://github.com/sanathp/statusok/blob/master/Config.md#mailgun)
 4. [Http EndPoint](https://github.com/sanathp/statusok/blob/master/Config.md#http-endpoint)
 5. [Dingding](https://github.com/sanathp/statusok/blob/master/Config.md#dingding)
+6. [Telegram](https://github.com/sanathp/statusok/blob/master/Config.md#telegram)
 
 Adding support to other clients is simple.[view details](https://github.com/sanathp/statusok/blob/master/Config.md#write-your-own-notification-client)
 
diff --git a/notify/notify.go b/notify/notify.go
index b2f9671..b965bc9 100644
--- a/notify/notify.go
+++ b/notify/notify.go
@@ -13,6 +13,7 @@ type NotificationTypes struct {
 	MailNotify MailNotify      `json:"mail"`
 	Mailgun    MailgunNotify   `json:"mailGun"`
 	Slack      SlackNotify     `json:"slack"`
+	Telegram   TelegramNotify  `json:"telegram"`
 	Http       HttpNotify      `json:"httpEndPoint"`
 	Dingding   DingdingNotify  `json:"dingding"`
 	Pagerduty  PagerdutyNotify `json:"pagerduty"`
diff --git a/notify/telegram_notify.go b/notify/telegram_notify.go
new file mode 100644
index 0000000..7070182
--- /dev/null
+++ b/notify/telegram_notify.go
@@ -0,0 +1,109 @@
+package notify
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"fmt"
+)
+
+type TelegramNotify struct {
+	BotToken          string `json:"botToken"`
+	ChatID            string `json:"chatID"`
+}
+
+type telegramPostMessage struct {
+	ChatID   string `json:"chat_id"`
+	Text     string `json:"text,omitempty"`
+}
+
+func (telegramNotify TelegramNotify) GetClientName() string {
+	return "Telegram"
+}
+
+func (telegramNotify TelegramNotify) Initialize() error {
+
+	if len(strings.TrimSpace(telegramNotify.BotToken)) == 0 {
+		return errors.New("Telegram: botToken is a required field")
+	}
+
+	if len(strings.TrimSpace(telegramNotify.ChatID)) == 0 {
+		return errors.New("Telegram: chatID is a required field")
+	}
+
+	return nil
+}
+
+func (telegramNotify TelegramNotify) SendResponseTimeNotification(responseTimeNotification ResponseTimeNotification) error {
+
+	message := getMessageFromResponseTimeNotification(responseTimeNotification)
+
+	payload, jsonErr := telegramNotify.getJsonParamBody(message)
+
+	if jsonErr != nil {
+		return jsonErr
+	}
+
+	requestURL := fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", telegramNotify.BotToken)
+
+	getResponse, respErr := http.Post(requestURL, "application/json", payload)
+
+	if respErr != nil {
+		return respErr
+	}
+
+	defer getResponse.Body.Close()
+
+	if getResponse.StatusCode != http.StatusOK {
+		return errors.New("Telegram : Send notifaction failed. Response code " + strconv.Itoa(getResponse.StatusCode))
+	}
+
+	return nil
+}
+
+func (telegramNotify TelegramNotify) SendErrorNotification(errorNotification ErrorNotification) error {
+
+	message := getMessageFromErrorNotification(errorNotification)
+
+	payload, jsonErr := telegramNotify.getJsonParamBody(message)
+
+	if jsonErr != nil {
+		return jsonErr
+	}
+
+	requestURL := fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", telegramNotify.BotToken)
+
+	getResponse, respErr := http.Post(requestURL, "application/json", payload)
+
+	if respErr != nil {
+		return respErr
+	}
+
+	defer getResponse.Body.Close()
+
+	if getResponse.StatusCode != http.StatusOK {
+		return errors.New("Telegram : Send notifaction failed. Response code " + strconv.Itoa(getResponse.StatusCode))
+	}
+
+	return nil
+}
+
+func (telegramNotify TelegramNotify) getJsonParamBody(message string) (io.Reader, error) {
+
+	data, jsonErr := json.Marshal(telegramPostMessage{telegramNotify.ChatID,
+		message,
+	})
+
+	if jsonErr != nil {
+
+		jsonErr = errors.New("Invalid Parameters for Content-Type application/json : " + jsonErr.Error())
+
+		return nil, jsonErr
+	}
+
+	return bytes.NewBuffer(data), nil
+}
diff --git a/sample_config.json b/sample_config.json
index 04b5d68..fc04970 100644
--- a/sample_config.json
+++ b/sample_config.json
@@ -29,6 +29,10 @@
 		"username":"statusok",
 		"channelWebhookURL":"https://hooks.slack.com/services/T09ZQZhET2E5Tl7"
 	},
+	"telegram":{
+		"botToken":"xxxxxx:xxxx-xxxxxxxxxxxxxxxx",
+		"chatID":"-1001027884121"
+	},
 	"mailGun":{
 		"email":"statusok@gmail.com",
 		"apiKey":"key-a8215497fc0",