LuaScripts.php

TLDR

The LuaScripts.php file in the Illuminate\Queue namespace contains a class called LuaScripts with several static methods. These methods are specifically used to generate Lua scripts that are utilized in queue-related operations.

Methods

size

This method returns a Lua script that computes the size of a queue. It takes three parameters representing the names of the primary queue, delayed queue, and reserved queue.

push

This method returns a Lua script that pushes jobs onto a queue. It takes three parameters: the queue key, the notification list key, and the job payload.

pop

This method returns a Lua script that pops the next job off a queue. It takes three parameters: the queue key, the reserved queue key, the notify queue key, and the expiration time for the reserved job.

release

This method returns a Lua script that releases reserved jobs. It takes two parameters representing the delayed queue key, the reserved queue key, the job payload, and the UNIX timestamp at which the job should become available.

migrateExpiredJobs

This method returns a Lua script that migrates expired jobs back onto a queue. It takes three parameters: the current queue key, the destination queue key, the notification list key, and the current UNIX timestamp.

clear

This method returns a Lua script that removes all jobs from the queue. It takes four parameters: the primary queue key, the delayed queue key, the reserved queue key, and the notify queue key.

Classes

There are no classes in this file.

<?php

namespace Illuminate\Queue;

class LuaScripts
{
    /**
     * Get the Lua script for computing the size of queue.
     *
     * KEYS[1] - The name of the primary queue
     * KEYS[2] - The name of the "delayed" queue
     * KEYS[3] - The name of the "reserved" queue
     *
     * @return string
     */
    public static function size()
    {
        return <<<'LUA'
return redis.call('llen', KEYS[1]) + redis.call('zcard', KEYS[2]) + redis.call('zcard', KEYS[3])
LUA;
    }

    /**
     * Get the Lua script for pushing jobs onto the queue.
     *
     * KEYS[1] - The queue to push the job onto, for example: queues:foo
     * KEYS[2] - The notification list for the queue we are pushing jobs onto, for example: queues:foo:notify
     * ARGV[1] - The job payload
     *
     * @return string
     */
    public static function push()
    {
        return <<<'LUA'
-- Push the job onto the queue...
redis.call('rpush', KEYS[1], ARGV[1])
-- Push a notification onto the "notify" queue...
redis.call('rpush', KEYS[2], 1)
LUA;
    }

    /**
     * Get the Lua script for popping the next job off of the queue.
     *
     * KEYS[1] - The queue to pop jobs from, for example: queues:foo
     * KEYS[2] - The queue to place reserved jobs on, for example: queues:foo:reserved
     * KEYS[3] - The notify queue
     * ARGV[1] - The time at which the reserved job will expire
     *
     * @return string
     */
    public static function pop()
    {
        return <<<'LUA'
-- Pop the first job off of the queue...
local job = redis.call('lpop', KEYS[1])
local reserved = false

if(job ~= false) then
    -- Increment the attempt count and place job on the reserved queue...
    reserved = cjson.decode(job)
    reserved['attempts'] = reserved['attempts'] + 1
    reserved = cjson.encode(reserved)
    redis.call('zadd', KEYS[2], ARGV[1], reserved)
    redis.call('lpop', KEYS[3])
end

return {job, reserved}
LUA;
    }

    /**
     * Get the Lua script for releasing reserved jobs.
     *
     * KEYS[1] - The "delayed" queue we release jobs onto, for example: queues:foo:delayed
     * KEYS[2] - The queue the jobs are currently on, for example: queues:foo:reserved
     * ARGV[1] - The raw payload of the job to add to the "delayed" queue
     * ARGV[2] - The UNIX timestamp at which the job should become available
     *
     * @return string
     */
    public static function release()
    {
        return <<<'LUA'
-- Remove the job from the current queue...
redis.call('zrem', KEYS[2], ARGV[1])

-- Add the job onto the "delayed" queue...
redis.call('zadd', KEYS[1], ARGV[2], ARGV[1])

return true
LUA;
    }

    /**
     * Get the Lua script to migrate expired jobs back onto the queue.
     *
     * KEYS[1] - The queue we are removing jobs from, for example: queues:foo:reserved
     * KEYS[2] - The queue we are moving jobs to, for example: queues:foo
     * KEYS[3] - The notification list for the queue we are moving jobs to, for example queues:foo:notify
     * ARGV[1] - The current UNIX timestamp
     *
     * @return string
     */
    public static function migrateExpiredJobs()
    {
        return <<<'LUA'
-- Get all of the jobs with an expired "score"...
local val = redis.call('zrangebyscore', KEYS[1], '-inf', ARGV[1], 'limit', 0, ARGV[2])

-- If we have values in the array, we will remove them from the first queue
-- and add them onto the destination queue in chunks of 100, which moves
-- all of the appropriate jobs onto the destination queue very safely.
if(next(val) ~= nil) then
    redis.call('zremrangebyrank', KEYS[1], 0, #val - 1)

    for i = 1, #val, 100 do
        redis.call('rpush', KEYS[2], unpack(val, i, math.min(i+99, #val)))
        -- Push a notification for every job that was migrated...
        for j = i, math.min(i+99, #val) do
            redis.call('rpush', KEYS[3], 1)
        end
    end
end

return val
LUA;
    }

    /**
     * Get the Lua script for removing all jobs from the queue.
     *
     * KEYS[1] - The name of the primary queue
     * KEYS[2] - The name of the "delayed" queue
     * KEYS[3] - The name of the "reserved" queue
     * KEYS[4] - The name of the "notify" queue
     *
     * @return string
     */
    public static function clear()
    {
        return <<<'LUA'
local size = redis.call('llen', KEYS[1]) + redis.call('zcard', KEYS[2]) + redis.call('zcard', KEYS[3])
redis.call('del', KEYS[1], KEYS[2], KEYS[3], KEYS[4])
return size
LUA;
    }
}