Simple script to move jobs scheduled in the future with resque-scheduler to Solid Queue or any other adapter

resque_scheduler_to_solid_queue.rb

# To count jobs still scheduled in the future with Resque
# Resque.redis.zcount(:delayed_queue_schedule, "-inf", "+inf")

# `job_data` from Resque (Redis)
def decode_job(job_data)
  job_json = JSON.parse(job_data).dig("args").first
  job_class = job_json["job_class"]
  job_arguments = ActiveJob::Arguments.deserialize(job_json["arguments"])

  { job_class: job_class, job_arguments: job_arguments }
rescue ActiveJob::DeserializationError
end

# Depending on the number of jobs, this will need to be done on a loop until there aren't any more jobs
# In our case, most jobs scheduled in the future were stored in the DB using an in-house gem, so we had 
# less than 100,000 jobs to move from Resque. All of those were ActiveRecord::DestroyJob
job_timestamps = Array(Resque.redis.zrange(:delayed_queue_schedule, 0, 100000))

jobs = []

job_timestamps.each do |timestamp|
  time = Time.at(timestamp.to_i)
  next if time < 10.minutes.from_now # let those be dispatched by Resque

  key = "delayed:#{timestamp}"
  Resque.redis.lrange(key, 0, -1).each do |job_data|
    job = decode_job(job_data)
    if job && (job_class = job[:job_class].safe_constantize)
      jobs << job_data
      # This would enqueue that job in the adapter the job is configured for (:solid_queue or any other)
      job_class.set(wait_until: time).perform_later(*job[:job_arguments])
      Resque.send :remove_delayed_job, job_data
    end
  end
end