zenpulse-scheduler 0.1.4

A DB-driven APScheduler for Django

⚡ ZenPulse Scheduler for Django

Modern, Hybrid, and Zero-Latency Job Scheduler

ZenPulse Scheduler is a Developer-First background job scheduler for Django. Unlike traditional schedulers that either rely on heavy external infrastructure (Redis/Celery) or spam your database with polling queries, ZenPulse uses a Smart Hybrid Architecture.

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🌟 Features

• ✅ No Redis/Celery Required - Pure Django solution
• ✅ Zero DB Impact - Smart file-based signaling system
• ✅ Hybrid Execution - Config in DB, Runtime in RAM
• ✅ Selective Logging - Log everything, nothing, or only failures
• ✅ Live Updates - Change schedules without restarting
• ✅ Multi-Process Safe - Built-in locking mechanisms
• ✅ Interval & Cron Support - Flexible scheduling options

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📦 Installation

Step 1: Install the Package

pip install zenpulse-scheduler

Or if installing from source:

cd /path/to/package
pip install -e .

Step 2: Add to Django Settings

# settings.py
INSTALLED_APPS = [
    # ... other apps
    'zenpulse_scheduler',
]

Step 3: Run Migrations

python manage.py migrate

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🚀 Quick Start Guide

1. Define Your Job

Create a file (e.g., yourapp/jobs.py) and register your job:

from zenpulse_scheduler.registry import zenpulse_job

@zenpulse_job("send_daily_report")
def send_daily_report():
    """Send daily sales report via email"""
    print("📧 Sending daily report...")
    # Your business logic here

Important: Make sure this file is imported when Django starts. You can do this by:

# yourapp/apps.py
from django.apps import AppConfig

class YourAppConfig(AppConfig):
    name = 'yourapp'
    
    def ready(self):
        import yourapp.jobs  # Import to register jobs

Or import it in your urls.py:

# yourapp/urls.py
import yourapp.jobs  # Ensure jobs are registered

urlpatterns = [
    # your urls
]

2. Start the Scheduler

Open a separate terminal and run:

python manage.py run_zenpulse_scheduler

You should see:

Starting ZenPulse Scheduler (Sync: 10s, Lock: False)...

3. Configure via Admin

1. Go to Django Admin → ZenPulse Scheduler → Schedule Configs
2. Click Add Schedule Config
3. Fill in the details (see Configuration Guide below)
4. Save

Your job will start running automatically!

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📚 Complete Configuration Guide

All job scheduling is controlled through the ScheduleConfig model in Django Admin.

Core Fields

Job Key (Required)

• Type: Text (Unique)
• Description: Must match the name you used in @zenpulse_job("name")
• Example: send_daily_report

Enabled (Required)

• Type: Checkbox
• Description: Controls whether the job runs
• Default: ✅ Checked (Enabled)
• Behavior:
  • ✅ Checked → Job runs according to schedule
  • ❌ Unchecked → Job stops immediately (within next sync interval)

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Trigger Configuration

Trigger Type (Required)

Choose how your job should be scheduled:

Choice	When to Use	Example
Interval	Repeating tasks that run in a loop	"Check for new emails every 5 minutes"
Cron	Tasks that run at specific calendar times	"Send report every Monday at 9 AM"

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Interval Configuration

Use when Trigger Type = Interval

Interval Value (Required for Interval)

• Type: Number
• Description: How many units to wait between runs
• Example: 30 (combined with unit below)

Interval Unit (Required for Interval)

Unit	Best For	Example Usage
Seconds	High-frequency monitoring, heartbeats	30 seconds = runs every 30 seconds
Minutes	Standard periodic tasks	15 minutes = runs every 15 minutes
Hours	Regular updates, data sync	4 hours = runs every 4 hours
Days	Daily routines	1 day = runs once per day
Weeks	Weekly maintenance	2 weeks = runs every 2 weeks

Example Configurations:

Interval Value: 10, Unit: Minutes → Runs every 10 minutes
Interval Value: 1, Unit: Hours → Runs every hour
Interval Value: 30, Unit: Seconds → Runs every 30 seconds

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Cron Configuration

Use when Trigger Type = Cron

All cron fields support:

• Specific values (e.g., 8 for 8 AM)
• Wildcards (* means "every")
• Lists (e.g., mon,wed,fri)
• Ranges (e.g., 1-5)

Cron Minute

• Valid Values: 0-59 or *
• Default: * (every minute)
• Examples:
  • 0 = At the top of the hour
  • 30 = At 30 minutes past the hour
  • */15 = Every 15 minutes

Cron Hour

• Valid Values: 0-23 or *
• Default: * (every hour)
• Examples:
  • 9 = 9 AM
  • 14 = 2 PM
  • 22 = 10 PM

Cron Day (of Month)

• Valid Values: 1-31 or *
• Default: * (every day)
• Examples:
  • 1 = 1st of the month
  • 15 = 15th of the month

Cron Month

• Valid Values: 1-12 or *
• Default: * (every month)
• Examples:
  • 1 = January
  • 12 = December

Cron Day of Week

• Valid Values: 0-6 (0=Sunday) or mon,tue,wed,thu,fri,sat,sun or *
• Default: * (every day)
• Examples:
  • mon = Every Monday
  • 0 = Every Sunday
  • mon,wed,fri = Monday, Wednesday, Friday

Example Cron Configurations:

Daily at 8:30 AM:
  Minute: 30, Hour: 8, Day: *, Month: *, Day of Week: *

Every Monday at 9 AM:
  Minute: 0, Hour: 9, Day: *, Month: *, Day of Week: mon

First day of every month at midnight:
  Minute: 0, Hour: 0, Day: 1, Month: *, Day of Week: *

Every weekday at 6 PM:
  Minute: 0, Hour: 18, Day: *, Month: *, Day of Week: mon,tue,wed,thu,fri

---

Advanced Options

Max Instances

• Type: Number
• Default: 1
• Description: Maximum number of this job that can run simultaneously
• Use Case: Set to 3 if you want to allow up to 3 parallel executions

Coalesce

• Type: Checkbox
• Default: ✅ Checked
• Description: If multiple runs were missed (e.g., scheduler was down), combine them into one
• Behavior:
  • ✅ Checked → Run once to catch up
  • ❌ Unchecked → Run all missed executions

Misfire Grace Time

• Type: Number (seconds)
• Default: 60
• Description: How long after the scheduled time the job can still run
• Example: If job was supposed to run at 10:00 but scheduler was busy, it can still run until 10:01 (60 seconds grace)

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Logging Configuration

Log Policy

Control how much execution history is saved to the database:

Policy	What Gets Logged	Database Impact	Best For
None	Nothing	Zero writes	High-frequency jobs (every few seconds)
Failures Only	Only when job crashes	Minimal writes	Production critical jobs (recommended)
All Executions	Every success and failure	High writes	Debugging, auditing

Recommendation: Use Failures Only for production. This way:

• ✅ You get full error traces when something breaks
• ✅ Database stays clean
• ✅ You can still monitor job health

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🖥️ Admin Panel Examples

Example 1: Send Email Every 30 Minutes

Job Key: send_email_digest
Enabled: ✅
Trigger Type: Interval
Interval Value: 30
Interval Unit: Minutes
Log Policy: Failures Only

Example 2: Daily Report at 8:30 AM

Job Key: generate_daily_report
Enabled: ✅
Trigger Type: Cron
Cron Minute: 30
Cron Hour: 8
Cron Day: *
Cron Month: *
Cron Day of Week: *
Log Policy: All Executions

Example 3: Weekly Cleanup Every Sunday at Midnight

Job Key: weekly_cleanup
Enabled: ✅
Trigger Type: Cron
Cron Minute: 0
Cron Hour: 0
Cron Day: *
Cron Month: *
Cron Day of Week: sun
Log Policy: Failures Only

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⚙️ Running the Scheduler

Development

python manage.py run_zenpulse_scheduler

Production (with Safety Lock)

python manage.py run_zenpulse_scheduler --lock

The --lock flag prevents multiple scheduler instances from running simultaneously:

• PostgreSQL: Uses advisory locks (recommended)
• MySQL: Uses GET_LOCK
• SQLite/Others: Uses file-based locking

Custom Sync Interval

By default, the scheduler checks for config changes every 10 seconds. To reduce database queries:

python manage.py run_zenpulse_scheduler --sync-every 60

This checks only once per minute. Trade-off: Changes take up to 60 seconds to apply.

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🏗️ Architecture

┌─────────────────┐
│  Django Admin   │  ← You configure jobs here
└────────┬────────┘
         │ Save Config
         ↓
┌─────────────────┐
│    Database     │  ← Stores ScheduleConfig
└────────┬────────┘
         │ Sync (every 10s)
         ↓
┌─────────────────┐
│   Scheduler     │  ← Runs in separate process
│   (Memory)      │
└────────┬────────┘
         │ Execute
         ↓
┌─────────────────┐
│   Your Job      │  ← @zenpulse_job decorated function
└─────────────────┘

Key Points:

1. Configuration lives in Database (persistent)
2. Execution happens in Memory (fast)
3. Scheduler syncs config changes automatically
4. No Redis or external dependencies needed

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📊 Monitoring Job Execution

View Execution Logs

Go to Django Admin → ZenPulse Scheduler → Job Execution Logs

You'll see:

• Job Key: Which job ran
• Status: Success or Fail
• Run Time: When it executed (with seconds precision)
• Duration: How long it took (in milliseconds)
• Exception Details: Full traceback if it failed

Understanding Log Entries

Job Key: send_email_digest
Status: Success
Run Time: 2026-02-01 14:30:45
Duration: 234.5 ms

If a job fails:

Job Key: send_email_digest
Status: Fail
Run Time: 2026-02-01 14:30:45
Exception Type: SMTPException
Exception Message: Connection refused
Traceback: [Full Python traceback here]

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🔧 Troubleshooting

Job Not Running?

1. Check if job is registered:

   # In Django shell
   from zenpulse_scheduler.registry import JobRegistry
   print(JobRegistry.get_all_jobs())
   

   Your job should appear in the list.

2. Check if enabled in Admin:

   • Go to Schedule Configs
   • Verify Enabled is checked

3. Check scheduler is running:

   • Look for Starting ZenPulse Scheduler... in terminal
   • Check for any error messages

Duplicate Executions?

• Make sure only one run_zenpulse_scheduler process is running
• Use --lock flag in production
• Check if you accidentally started it in multiple terminals

Jobs Running at Wrong Time?

• Verify your TIME_ZONE setting in Django settings
• Check cron configuration carefully
• Use Interval for simple repeating tasks

Database Performance Issues?

• Set Log Policy to None or Failures Only
• Increase --sync-every to reduce config checks
• Consider archiving old logs periodically

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🚀 Production Deployment

Using Systemd (Linux)

Create /etc/systemd/system/zenpulse-scheduler.service:

[Unit]
Description=ZenPulse Scheduler
After=network.target

[Service]
Type=simple
User=www-data
WorkingDirectory=/path/to/your/project
ExecStart=/path/to/venv/bin/python manage.py run_zenpulse_scheduler --lock --sync-every 30
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target

Enable and start:

sudo systemctl enable zenpulse-scheduler
sudo systemctl start zenpulse-scheduler
sudo systemctl status zenpulse-scheduler

Using Supervisor

[program:zenpulse-scheduler]
command=/path/to/venv/bin/python manage.py run_zenpulse_scheduler --lock
directory=/path/to/your/project
user=www-data
autostart=true
autorestart=true
redirect_stderr=true
stdout_logfile=/var/log/zenpulse-scheduler.log

Using Docker

# In your Dockerfile
CMD ["python", "manage.py", "run_zenpulse_scheduler", "--lock"]

Or in docker-compose.yml:

services:
  scheduler:
    build: .
    command: python manage.py run_zenpulse_scheduler --lock
    depends_on:
      - db

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❓ FAQ

Q: Can I run this with Gunicorn/Uvicorn?
A: Yes, but run the scheduler in a separate process/container. Never run it inside web workers.

Q: What happens if I restart the server?
A: Configuration is in the database, so it persists. Just start the scheduler command again.

Q: Can jobs accept parameters?
A: Currently, jobs should be parameter-less functions. For different parameters, create separate job functions.

Q: How do I delete old logs?
A: You can manually delete from Admin or create a cleanup job:

@zenpulse_job("cleanup_old_logs")
def cleanup_old_logs():
    from datetime import timedelta
    from django.utils import timezone
    from zenpulse_scheduler.models import JobExecutionLog
    
    cutoff = timezone.now() - timedelta(days=30)
    JobExecutionLog.objects.filter(run_time__lt=cutoff).delete()

Q: Is this production-ready?
A: Yes! It's built on APScheduler (battle-tested library) with Django best practices.

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📝 License

[Your License Here]

🤝 Contributing

Contributions welcome! Please open an issue or PR.

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Made with ❤️ for Django developers who want simple, powerful scheduling.