BackendAssignment

🧠 queuectl — CLI-based Background Job Queue System

queuectl is a lightweight, production-style background job queue system built in Python.
It supports enqueuing shell commands as jobs, processing them with worker processes, retrying failures using exponential backoff, and maintaining a Dead Letter Queue (DLQ) for permanently failed jobs.

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✨ Features

• 🧾 Job management — enqueue, list, and inspect jobs
• ⚙️ Multiple workers — process jobs concurrently
• 🔁 Automatic retries — exponential backoff on failure
• 💀 Dead Letter Queue (DLQ) — permanently failed jobs are stored safely
• 💾 Persistent storage — jobs stored in SQLite (queue.db)
• 🧰 CLI interface — fully controllable from the terminal
• Dashboard for viewing - Fully viewable dashboard

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📦 Installation

git clone https://github.com/yourusername/queuectl.git
cd queuectl
chmod +x queuectl
sudo ln -s $(pwd)/queuectl /usr/local/bin/queuectl   # optional global usage

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Job Format

{
  "id": "job-1",
  "command": "echo 'Hello World'",
  "state": "pending",
  "attempts": 0,
  "max_retries": 3,
  "created_at": "2025-11-04T10:30:00Z",
  "updated_at": "2025-11-04T10:30:00Z"
}

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🚀 Usage

1️⃣ Enqueue a Job

./queuectl enqueue --json '{"id":"job3","command":"echo Hello","max_retries":2}'

or

./queuectl enqueue --command "ls-l"

Workers

./queuectl worker start --count 3

Status

    ./queuectl status 

Pending

queuectl list --state running

DLQ

Showing the status of the DLQ

./queuectl dlq show

Rescheduling the failed job

./queuectl dlq retry-job

Architecture Diagram