Notification message template (#3)

* Added: templates for messages

* Updated: docs

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## v1.0.2
+
+### Added
+- messages templates
+
 ## v1.0.1
 
 ### Added

README.md

@@ -164,7 +164,7 @@ services:
 ## Roadmap
 
 - [x] Add Changelog
-- [ ] Add the ability to change the text of messages
+- [x] Add the ability to change the text of messages
 - [ ] Send notifications to multiple channels/groups
 - [ ] Display event time in notifications
 - [ ] Online/offline time count

configs/config.example.yml

@@ -2,6 +2,9 @@ telegram:
   token: # токен бота
   chatId: -1234567890123 # ИД чата для уведомлений
   webhookUrl: # TODO: URL для получения веб-хуков, если не задан, то используется long-poll
+  messages:
+    online: "✅ {{.Name}} is *online*" # текст сообщения при переходе сервиса в состояние "в сети"
+    offline: "❌ {{.Name}} is *offline*: {{.Error}}" # текст сообщения при переходе сервиса в состояние "не в сети"
 services: # список сервисов для мониторинга
   - name: Google # наименование для уведомления
     initialDelaySeconds: 5 # пауза перед первым опросом в секундах, по умолчанию: 0; если меньше 0, то используется случайное значение между 0 и `periodSeconds`

internal/bot/app.go

@@ -20,6 +20,7 @@ func Run() error {
 	cfg := config.GetConfig()
 	ctx, _ := signal.NotifyContext(context.Background(), os.Interrupt)
 
+	messages := NewMessages(cfg.Telegram.Messages)
 	tg := infrastructure.NewTelegramBot(cfg.Telegram)
 	tgapi, err := tg.Api()
 	if err != nil {
@@ -40,9 +41,25 @@ func Run() error {
 		msg := tgbotapi.NewMessage(cfg.Telegram.ChatID, "")
 		msg.ParseMode = tgbotapi.ModeMarkdownV2
 		if v.State == monitor.ServiceOffline {
-			msg.Text = "❌ " + tgbotapi.EscapeText(msg.ParseMode, v.Name) + " is *offline*: " + tgbotapi.EscapeText(msg.ParseMode, v.Error.Error())
+			// msg.Text = "❌ " + tgbotapi.EscapeText(msg.ParseMode, v.Name) + " is *offline*: " + tgbotapi.EscapeText(msg.ParseMode, v.Error.Error())
+			context := OfflineContext{
+				OnlineContext: OnlineContext{
+					Name: tgbotapi.EscapeText(msg.ParseMode, v.Name),
+				},
+				Error: tgbotapi.EscapeText(msg.ParseMode, v.Error.Error()),
+			}
+			msg.Text, err = messages.Render(TemplateOffline, context)
 		} else {
-			msg.Text = "✅ " + tgbotapi.EscapeText(msg.ParseMode, v.Name) + " is *online*"
+			// msg.Text = "✅ " + tgbotapi.EscapeText(msg.ParseMode, v.Name) + " is *online*"
+			context := OnlineContext{
+				Name: tgbotapi.EscapeText(msg.ParseMode, v.Name),
+			}
+			msg.Text, err = messages.Render(TemplateOnline, context)
+		}
+
+		if err != nil {
+			errorLog.Println(err)
+			continue
 		}
 
 		if _, err := tgapi.Send(msg); err != nil {

internal/bot/messages.go

@@ -0,0 +1,73 @@
+package bot
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"text/template"
+
+	"github.com/capcom6/service-monitor-tgbot/internal/config"
+)
+
+type TemplateName string
+
+const (
+	TemplateOnline  TemplateName = "online"
+	TemplateOffline TemplateName = "offline"
+)
+
+type Messages struct {
+	Templates       config.TelegramMessages
+	cachedTemplates map[TemplateName]*template.Template
+	mux             sync.Mutex
+}
+
+type OnlineContext struct {
+	Name string
+}
+
+type OfflineContext struct {
+	OnlineContext
+	Error string
+}
+
+func NewMessages(templates config.TelegramMessages) *Messages {
+	return &Messages{
+		Templates:       templates,
+		cachedTemplates: make(map[TemplateName]*template.Template),
+	}
+}
+
+func (m *Messages) prepare(name TemplateName) (prepared *template.Template, err error) {
+	m.mux.Lock()
+	defer m.mux.Unlock()
+
+	if prepared = m.cachedTemplates[name]; prepared != nil {
+		return prepared, nil
+	}
+
+	var tmplString string
+	var ok bool
+	if tmplString, ok = m.Templates[string(name)]; !ok {
+		return nil, fmt.Errorf("template %s not found", name)
+	}
+
+	if m.cachedTemplates[name], err = template.New(string(name)).Parse(tmplString); err != nil {
+		return nil, fmt.Errorf("can't parse template %s: %w", name, err)
+	}
+
+	return m.cachedTemplates[name], nil
+}
+
+func (m *Messages) Render(name TemplateName, context any) (string, error) {
+	tmpl, err := m.prepare(name)
+	if err != nil {
+		return "", err
+	}
+
+	builder := strings.Builder{}
+	if err := tmpl.Execute(&builder, context); err != nil {
+		return "", err
+	}
+	return builder.String(), nil
+}

internal/config/config.go

@@ -20,11 +20,13 @@ type Config struct {
 	Storage  Storage   `yaml:"storage"`
 }
 type Telegram struct {
-	Token      string `yaml:"token" envconfig:"TELEGRAM__TOKEN" validate:"required"`
-	ChatID     int64  `yaml:"chatId" envconfig:"TELEGRAM__CHAT_ID"`
-	WebhookURL string `yaml:"webhookUrl" envconfig:"TELEGRAM__WEBHOOK_URL" validate:"required"`
-	Debug      bool   `yaml:"debug" envconfig:"TELEGRAM__DEBUG"`
+	Token      string           `yaml:"token" envconfig:"TELEGRAM__TOKEN" validate:"required"`
+	ChatID     int64            `yaml:"chatId" envconfig:"TELEGRAM__CHAT_ID"`
+	WebhookURL string           `yaml:"webhookUrl" envconfig:"TELEGRAM__WEBHOOK_URL" validate:"required"`
+	Debug      bool             `yaml:"debug" envconfig:"TELEGRAM__DEBUG"`
+	Messages   TelegramMessages `yaml:"messages"`
 }
+type TelegramMessages map[string]string
 type HTTPHeader struct {
 	Name  string `yaml:"name"`
 	Value string `yaml:"value"`
@@ -170,7 +172,7 @@ func loadConfig() Config {
 		path = "config.yml"
 	}
 
-	config := Config{}
+	config := defaultConfig
 
 	if err := fromYaml(path, &config); err != nil {
 		errorLog.Printf("couldn'n load config from %s: %s\r\n", path, err.Error())
@@ -205,5 +207,7 @@ func GetConfig() Config {
 		instance = loadConfig()
 	})
 
+	log.Printf("config: %+v", instance)
+
 	return instance
 }

internal/config/defaults.go

@@ -0,0 +1,20 @@
+package config
+
+var (
+	defaultTelegramMessages TelegramMessages = TelegramMessages{
+		"online":  "✅ {{.Name}} is *online*",
+		"offline": "❌ {{.Name}} is *offline*: {{.Error}}",
+	}
+
+	defaultConfig Config = Config{
+		Telegram: Telegram{
+			Token:      "",
+			ChatID:     0,
+			WebhookURL: "",
+			Debug:      false,
+			Messages:   defaultTelegramMessages,
+		},
+		Services: []Service{},
+		Storage:  Storage{},
+	}
+)