Ricardo Leal

DBOS Experiments: Experiment 4

2026-01-04

GitHub: dbos_experiments/exp4

Experiment 4

Summary

This experiment demonstrates a comprehensive DBOS web application featuring real-time communication, scheduled workflows, and an interactive web interface. It showcases an access request management system with WebSocket integration, multiple queues, and real-time notifications.

Files Description

Core Application Files

  • main.py - Full-featured FastAPI application with DBOS integration containing:
    • WebSocket Support: Real-time data updates to connected clients
    • Scheduled Workflows: Automated data refresh every 5 seconds using cron-style scheduling
    • Multiple Queues: Separate queues for Slack, email, and request processing
    • Access Management System: Complete workflow for requesting and approving access
    • Real-time Notifications: WebSocket-based notifications for approval/rejection
    • Static File Serving: Serves static assets and HTML templates
    • API Endpoints:
      • GET / - Main web interface
      • POST /api/request/{user_id}/{access_id} - Submit access requests
      • POST /api/approve - Approve/reject access requests
      • WebSocket /ws/data - Real-time data streaming
  • models.py - Complex SQLAlchemy database schema:
    • Base - SQLAlchemy declarative base class
    • Users - User management with unique email constraints
    • Accesses - Access definitions and descriptions
    • AccessRequests - Junction table linking users to access with status tracking
    • Errors - Error logging with JSONB message storage
    • Full relationship mapping between entities

Web Interface Files

  • templates/index.html - Interactive web dashboard featuring:
    • Real-time Data Table: Auto-refreshing access requests display
    • Action Buttons: Approve/reject functionality with dynamic state
    • Status-based Styling: Color-coded rows based on request status
    • Notification System: Real-time toast notifications with icons
    • Form Interface: User-friendly access request submission
    • Responsive Design: Bootstrap-based responsive layout
    • WebSocket Integration: Live data updates without page refresh
    • Sortable Tables: Client-side sorting by columns
  • static/ - Directory for static assets (CSS, JS, images)

Configuration Files

  • __init__.py - Python package initialization file

  • dbos-config.yaml - DBOS configuration for database and application settings

  • envrc-template - Environment variables template for direnv integration

Database Migration Files

  • migrations/ - Alembic database migration directory

Key Features Demonstrated

  • Real-time Communication: WebSocket-based live updates
  • Scheduled Workflows: Automated background tasks with cron scheduling
  • Multi-queue Architecture: Separate processing queues for different notification types
  • Interactive Web UI: Full-featured dashboard with real-time updates
  • Access Management: Complete workflow from request to approval/rejection
  • Error Handling: Comprehensive error tracking and logging
  • Notification System: Multi-channel notifications (Slack, Email simulation)

Development

Run docker compose in the parent directory:

docker compose up

Alembic

# alembic init migrations

# export ALEMBIC_CONFIG=migrations/alembic.ini

# alembic revision -m "initial migration"

alembic upgrade head

Generate models from the database

# sqlacodegen --generator declarative --options nojoined  --outfile models.py $POSTGRES_URL

DBOS

# Alternative to alembic upgrade head
# dbos migrate

dbos start

DB

To inspect the database:

pgcli

Recent changes

  • 2026-01-17 8e83110 updated models
  • 2025-08-10 bdd71b7 added AI READMEs
  • 2025-02-13 f6ee876 backup
  • 2025-02-11 b6954ac working locally with access requests
  • 2025-02-09 b378615 backup
  • 2025-02-08 9ebc6a8 backup
  • 2025-02-08 d764b3b Divided experiments in folders

Categories: experiments, Python

Tags: dbos-experiments

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