Lineup

A lightweight, thread-safe queue management library for Go that allows you to control concurrent processing with automatic position tracking.

Features

• Thread-safe queue management - Built with mutex locks for safe concurrent access
• Concurrent processing control - Limit the number of items processed simultaneously
• Automatic position tracking (O(N)) - Items automatically receive their position in the queue
• Queue item purging - Remove items from the queue at any time
• Simple API - Easy to use with minimal configuration

Installation

go get github.com/a4amado/Lineup

Usage

Purging Items

You can remove items from the queue before they are processed. It's recommended to use defer to ensure cleanup:

queue := Lineup.New(Lineup.QueueOptions{
    MaxProcessing: 2,
})

place := queue.Place()
defer place.Purge()

for position := range place.Halt {
    fmt.Printf("Your posiion is %d", position)
}

Queue.Place() *QueueItem

Adds a new item to the queue and returns a QueueItem.

Returns: A pointer to a QueueItem that can be used to track position and purge the item

Example:

item := queue.Place()

QueueItem.Purge()

Removes the item from the queue. The item will be skipped during processing.

Example:

item.Purge()

QueueItem.Halt chan int

A channel that receives the item's position in the queue:

• 1 - The item can proceed (within the processing limit)
• > 1 - The item is waiting (position in line)

The queue automatically recalibrates positions every 300ms, so items will receive updated positions as the queue progresses.

Note: The Halt channel continuously receives position updates every 300ms. You should read from it in a loop to track position changes as items move through the queue.

How It Works

1. When you call Place(), a new item is added to the queue
2. A background goroutine continuously recalibrates item positions every 300ms
3. Items within the MaxProcessing limit receive position 1 (can proceed)
4. Items beyond the limit receive their actual position in line
5. Items can be purged at any time and will be removed from the queue

License

See LICENSE.txt for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.