que-scheduler vs sidekiq-scheduler for Ruby background jobs?

que-scheduler is tailored for Que and PostgreSQL users, offering database-backed reliability and seamless integration. Sidekiq-scheduler is better for Sidekiq and Redis environments, with similar cron features but different ecosystems. Choose based on your existing job queue stack.

How to handle time zones in que-scheduler without Rails?

You must explicitly set the time zone in the configuration block using a string like 'Europe/London'. Without Rails, que-scheduler cannot infer the time zone and will error until configured manually.

Can que-scheduler run multiple scheduler jobs for redundancy?

No, it enforces a single scheduler job via database constraints to prevent duplicates. High availability comes from Que workers, not multiple scheduler instances, ensuring consistency but limiting redundancy options.

What happens if the YAML schedule file changes during deployment?

que-scheduler automatically detects changes on each run and adjusts enqueued jobs accordingly. No restart is needed; it handles new, modified, or removed jobs seamlessly based on the updated configuration.

How does que-scheduler ensure jobs aren't missed after downtime?

Using the 'every_event' schedule type, jobs are enqueued for every missed cron match during downtime, with audit tables tracking executions. This ensures critical batch jobs run for each interval, even after outages.

Is there a way to monitor que-scheduler performance or errors?

Yes, audit tables provide detailed logs, and errors are reported via Que's standard error notifier. You can query the audit tables for insights or set up custom handlers for integration with monitoring tools.

Open-Awesome

que-scheduler

MITRubyv7.0.1

A cron scheduler extension for the Que async job worker, enabling scheduled background jobs via YAML configuration.

GitHub

115 stars23 forks0 contributors

What is que-scheduler?

que-scheduler is a Ruby gem that extends the Que job queue with cron-style scheduling capabilities. It allows developers to schedule background jobs using a YAML configuration file, ensuring jobs run at specified intervals even after system downtime. The scheduler itself runs as a Que job, leveraging the database for reliability and consistency.

Target Audience

Ruby developers using the Que job queue who need reliable, database-backed scheduling for background tasks, particularly in Rails applications or other PostgreSQL-based systems.

Value Proposition

Developers choose que-scheduler for its tight integration with Que, transactional reliability, and support for missed job execution after downtime via the `every_event` schedule type, avoiding the need for separate scheduler processes.

Overview

A lightweight cron scheduler for the async job worker Que

Use Cases

Best For

Scheduling periodic background jobs in Rails applications with Que
Ensuring critical batch jobs run even after system downtime or database restores
Replacing resque-scheduler or sidekiq-scheduler in Que-based systems
Auditing and monitoring scheduled job execution via built-in audit tables
Configuring job schedules via YAML for maintainability and version control
Running high-availability scheduling without separate daemon processes

Not Ideal For

Projects not using Que or PostgreSQL as their job queue and database
Applications requiring a graphical UI or admin dashboard for managing schedules
Teams needing cross-database or distributed scheduling across microservices

Pros & Cons

Pros

Reliable Cron Scheduling

Supports standard crontab syntax and simpler expressions like '@daily', with time zone options, using the fugit library for precise parsing and execution.

High Availability Design

Runs as a self-scheduling Que job leveraging PostgreSQL's ACID guarantees, ensuring no separate processes are needed and scheduling state survives database restores or downtime.

Comprehensive Audit Trail

Includes dedicated audit tables (que_scheduler_audit and que_scheduler_audit_enqueued) that log all scheduler runs and enqueued jobs, aiding in monitoring and debugging.

Concurrent Safety

Enforces a single scheduler job via database constraints and triggers, preventing duplicate scheduling and race conditions without manual intervention.

Cons

Que and PostgreSQL Lock-in

Tightly coupled to the Que job queue and PostgreSQL, making it unsuitable for projects using other job systems like Sidekiq or databases like MySQL.

Migration Complexity

Major version upgrades require database migrations that can be slow and disruptive, such as adding primary keys to large audit tables, with breaking changes necessitating careful planning.

Configuration Overhead for Non-Rails

Non-Rails applications must manually handle time zone configuration and other settings, as automatic inference relies on Rails, adding setup complexity.

Open Source Alternative To

que-scheduler is an open-source alternative to the following products:

sidekiq-scheduler

sidekiq-scheduler is a Ruby gem that adds cron-like job scheduling capabilities to Sidekiq, allowing periodic tasks to run at specified intervals.

resque-scheduler

resque-scheduler is a Resque plugin that adds scheduled jobs and recurring jobs to the Resque job queue system.

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