# RedisOban

A high-performance, Redis-backed job processing library for Elixir, inspired by Oban and BullMQ.

## Why RedisOban?

Traditional job queues in Elixir (like Oban) often use PostgreSQL for persistence. While reliable, this can put significant pressure on your primary database in high-throughput environments. `RedisOban` offloads job storage and coordination to Redis, providing:

- **Reduced DB Pressure**: Move high-churn job data out of Postgres.
- **Lower Latency**: Redis's in-memory operations and atomic primitives (like `BRPOPLPUSH`) enable faster job handling.
- **Reliability**: Uses a processing list pattern to ensure jobs aren't lost if a worker node crashes.

## Features

- **Concurrent Processing**: Configurable worker concurrency per node.
- **State Tracking**: Track jobs through `enqueued`, `processing`, `completed`, and `failed` states.
- **Reliable Consumer**: Automatic rescue of stalled jobs (e.g., node crashes) via the `Rescuer` process.
- **Retry Logic**: Automatic retries with configurable max attempts.
- **Clean Worker API**: Simple behavior-based workers.

## Architecture

1. **Storage**: Full job metadata is stored in Redis Keys (`oban:job:{id}`).
2. **Queuing**: Job IDs are moved between lists:
   - `oban:queue:{name}`: Pending jobs.
   - `oban:processing:{name}`: Active jobs (for reliability).
3. **Poller**: A GenServer that manages a pool of `Task` processes to execute jobs concurrently.
4. **Rescuer**: A watchdog process that recovers jobs stuck in the `processing` list for too long.

## Usage

### 1. Define a Worker

```elixir
defmodule MyApp.Workers.EchoWorker do
  use RedisOban.Worker

  @impl true
  def perform(%{"message" => message}) do
    IO.puts("Received: #{message}")
    :ok
  end
end
```

### 2. Enqueue a Job

```elixir
job = RedisOban.Job.new(MyApp.Workers.EchoWorker, %{"message" => "Hello World"})
RedisOban.insert(job)
```

### 3. Configuration

In your `application.ex`:

```elixir
children = [
  {Redix, name: RedisOban.Redis},
  {Task.Supervisor, name: RedisOban.TaskSupervisor},
  {RedisOban.Poller, [queue: "default", concurrency: 10]},
  {RedisOban.Rescuer, [queue: "default"]}
]
```

## Examples

You can find several example scripts in the `examples/` directory. Run them with `mix run`:

```bash
# Basic enqueuing and processing
mix run examples/basic_usage.exs

# Delayed jobs
mix run examples/scheduled_jobs.exs

# Priority demonstration
mix run examples/priority_queues.exs

# Failure and retry logic
mix run examples/retries.exs
```

## Future Roadmap

- [ ] **Scheduled Jobs**: Support for delayed execution using Sorted Sets.
- [ ] **Priority Queues**: Assign weights to different queues.
- [ ] **Dashboard**: A LiveView-based UI for monitoring.
- [ ] **Unique Jobs**: Prevent duplicate enqueuing of identical jobs.