The Lua Script to Reschedule a Job

reschedule.lua

redis.replicate_commands()
local job_id = ARGV[1]

-- source the jobs metadata for some accounting
metadata_key = 'jobs:' .. job_id
local job_metadata = redis.call('HMGET', metadata_key, 'tenant_id', 'queue')

local tenant_id = job_metadata[1]
local queue = job_metadata[2]

-- cleanup the job's running state
local running_jobs = queue .. '_running_jobs:' .. tenant_id
redis.call('SREM', running_jobs, job_id)

local pending_jobs = queue .. '_pending_jobs:' .. tenant_id
redis.call('LPUSH', pending_jobs, job_id)


-- if rescheduling this job made the tenant runnable, mark them as such
local limit = tonumber(redis.call('HGET', 'tenant_limits', queue))
local running_jobs_count = redis.call('SCARD', running_jobs)

if (running_jobs_count < limit) then
    local runnable_tenants = queue .. '_runnable_tenants'
    redis.call('SADD', runnable_tenants, tenant_id)
end