Telegram Notifications Setup

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Architecture Overview

1. Go-based Telegram bot (src/telegram-bot/main.go) - Handles message sending/receiving
2. NATS JetStream - Message broker for reliable notification delivery
3. Backend API - Manages notification channels and triggers alerts

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Prerequisites

• Telegram account
• Bot token from @BotFather
• NATS server running and accessible
• Authenticated PriceSignal account

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Bot Configuration

TELEGRAM_BOT_TOKEN=your_bot_token_here
NATS_URL=nats://localhost:4222

cd src/telegram-bot
go run main.go

Authorized on account YourBotName

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How It Works

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Registration Flow

1. Bot receives message with your user ID (main.go:99-128):
   chatID := update.Message.Chat.ID
   username := update.Message.From.UserName
   userId := update.Message.CommandArguments()
   
2. Message published to NATS on notifications.init.telegram subject:
   chatIDMessage := ChatIDMessage{
       ChatID:   chatID,
       Username: username,
       UserId:   userId,
   }
   data, _ := json.Marshal(chatIDMessage)
   js.PublishAsync("notifications.init.telegram", data)
   
3. Backend receives registration (Program.cs:216-240):
   natsService.Subscribe<TelegramInit>("notifications", message =>
   {
       var user = dbContext.Users.FirstOrDefault(u => 
           u.Id == message.User_Id &&
           u.NotificationChannels.FirstOrDefault(nc => 
               nc.TelegramChatId == message.Chat_Id) == null);
       
       if (user != null)
       {
           var channel = new UserNotificationChannel
           {
               User = user,
               ChannelType = NotificationChannelType.telegram,
               TelegramChatId = message.Chat_Id,
               TelegramUsername = message.Username
           };
           dbContext.UserNotificationChannels.Add(channel);
           dbContext.SaveChanges();
       }
   }, "notifications.init.telegram");
   

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Notification Delivery

1. Backend publishes notification to NATS on notifications.telegram subject
2. Bot consumes message via JetStream consumer (main.go:72-92):
   c, _ := s.CreateOrUpdateConsumer(ctx, jetstream.ConsumerConfig{
       Durable:       "telegram",
       FilterSubject: "notifications.telegram",
       AckPolicy:     jetstream.AckExplicitPolicy,
   })
   
   c.Consume(func(msg jetstream.Msg) {
       var notification Notification
       json.Unmarshal(msg.Data(), &notification)
       
       telegramMsg := tgbotapi.NewMessage(notification.ChatID, notification.Message)
       bot.Send(telegramMsg)
       msg.Ack()
   })
   
3. Message sent to your Telegram chat

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Message Format

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Registration Message

{
  "chat_id": 123456789,
  "username": "your_username",
  "user_id": "firebase_user_id"
}

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Notification Message

{
  "chat_id": 123456789,
  "message": "Alert: BTC has reached $50,000"
}

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NATS Configuration

js, _ := jetstream.New(nc)
s, _ := js.CreateOrUpdateStream(ctx, jetstream.StreamConfig{
    Name:     "notifications",
    Subjects: []string{"notifications.>"},
})

• Name: notifications
• Subjects: notifications.* (wildcard for all notification types)
• Consumer: Durable consumer named telegram for persistent subscription

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Managing Notification Channels

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Query Notification Channels

query GetMyNotificationChannels {
  notificationChannels {
    edges {
      node {
        id
        channelType
        telegramChatId
        telegramUsername
        createdAt
      }
    }
  }
}

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Delete Notification Channel

mutation DeleteNotificationChannel($id: UUID!) {
  deleteNotificationChannel(id: $id) {
    id
  }
}

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Multiple Accounts

1. Send the bot command from different Telegram accounts
2. Each account will be registered as a separate notification channel
3. Alerts will be sent to all registered channels

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Troubleshooting

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Bot not responding

• Verify bot token is correct in .env
• Check bot is running: ps aux | grep telegram-bot
• Ensure bot is not blocked in Telegram settings

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Not receiving notifications

• Confirm notification channel is registered:
  query { notificationChannels { edges { node { telegramChatId } } } }
  
• Check NATS server is running and accessible
• Verify price rules are enabled
• Check bot logs for errors

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Chat ID not recorded

• Ensure user ID is passed correctly in the command
• Verify user exists in database
• Check backend logs for NATS subscription errors

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Production Deployment

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Systemd Service Example

[Unit]
Description=PriceSignal Telegram Bot
After=network.target nats.service

[Service]
Type=simple
User=pricesignal
WorkingDirectory=/opt/pricesignal/telegram-bot
EnvironmentFile=/opt/pricesignal/telegram-bot/.env
ExecStart=/opt/pricesignal/telegram-bot/telegram-bot
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

sudo systemctl enable pricesignal-telegram
sudo systemctl start pricesignal-telegram

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Docker Deployment

FROM golang:1.21-alpine AS builder
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN go build -o telegram-bot main.go

FROM alpine:latest
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=builder /app/telegram-bot .
CMD ["./telegram-bot"]

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Security Considerations

• Never commit bot tokens to version control
• Use environment variables for all sensitive configuration
• Validate user IDs before creating notification channels
• Consider implementing rate limiting for bot commands
• Use NATS authentication in production environments
• Enable TLS for NATS connections

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Next Steps