System Architecture¶

Meet Transcriber is a single-server Node.js application that orchestrates multiple subsystems: browser automation, audio capture, transcription, and notification delivery.

Module Overview¶

Module	File	Responsibility
Orchestrator	`src/index.js`	Entry point; coordinates all modules, manages PM2 lifecycle
Scheduler	`src/scheduler.js`	Browser-based Google Calendar polling via Puppeteer
Google Login	`src/google-login.js`	Google auth, session persistence, 2FA backup codes
Joiner	`src/joiner.js`	Joins Google Meet using headless Chrome
Recorder	`src/recorder.js`	Captures audio via PulseAudio virtual device + FFmpeg
Transcriber	`src/transcriber.js`	Sends audio file to OpenAI Whisper API
Notifier	`src/notifier.js`	Telegram bot + status API event logging
Database	`src/db.js`	SQLite state persistence (meetings, sessions)
Config	`src/config.js`	Environment config loader (reads `.env`)
Error Watcher	`src/error-watcher.js`	Monitors PM2 logs for crashes; triggers alerts

Data Flow¶

┌─────────────────────────────────────────────────────────────────────────────┐
│                        DigitalOcean Server (Ubuntu 24.04)                   │
│                              104.131.17.141                                 │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│  ┌─────────────┐    ┌─────────────────┐    ┌─────────────────────────────┐  │
│  │  Scheduler  │───▶│  Meeting Joiner │───▶│      Audio Recorder         │  │
│  │  (Calendar  │    │  (Puppeteer +   │    │  (PulseAudio + FFmpeg)      │  │
│  │   Poller)   │    │  Headless Chrome│    │                             │  │
│  └──────┬──────┘    └────────┬────────┘    └────────────┬────────────────┘  │
│         │                    │                          │                   │
│  Google Calendar         meet.google.com            audio.mp3               │
│  (browser scrape)        (browser join)           (virtual sink)            │
│         │                    │                          │                   │
│         ▼                    ▼                          ▼                   │
│  ┌─────────────┐    ┌─────────────────┐    ┌─────────────────────────────┐  │
│  │  SQLite DB  │    │    Notifier     │    │      Transcriber            │  │
│  │  (state)    │    │  (Telegram Bot) │    │  (OpenAI Whisper API)       │  │
│  └─────────────┘    └─────────────────┘    └─────────────────────────────┘  │
│                              │                          │                   │
│                              └──────────────────────────┘                   │
│                              Transcript → Telegram                          │
└─────────────────────────────────────────────────────────────────────────────┘

Step-by-step Flow¶

Calendar Poll — scheduler.js uses Puppeteer to navigate meet.google.com/landing and scan for upcoming meeting cards
Meeting Detected — when a meeting is found within the join window, the scheduler emits the meeting URL
Browser Join — joiner.js navigates to the Meet URL, mutes mic/camera, clicks the join button
Audio Capture — recorder.js spawns FFmpeg to record from the PulseAudio virtual sink (which captures Chrome audio output)
Recording Saved — audio file written to /root/meet-transcriber/recordings/ as MP3
Transcription — transcriber.js sends the MP3 to OpenAI Whisper API; receives transcript text
Telegram Delivery — notifier.js sends the transcript (and all status updates) to the configured Telegram bot
Event Log — every notification is appended to the JSONL event log and visible on the status dashboard

PM2 Processes¶

Process	Description
`meet-transcriber`	Main bot — headless browser, scheduler, recorder, transcriber
`meet-status`	Status API server (port 3456) — dashboard + API
`error-watcher`	Watches PM2 logs for crash patterns; fires alerts

Infrastructure¶

Component	Details
Web server	Nginx (reverse proxy for status site)
SSL	Let's Encrypt (auto-renews via certbot)
Process manager	PM2 (`ecosystem.config.cjs`)
Storage	Local filesystem + SQLite