What is the best way to perform a periodic task in docker?

Question

Docker

Docker old 1.7.1, Redis containers, MySQL, working (php cli + add-ons). The worker waits for the next video rendering task from Redis and executes it.
For monitoring, you need to take the queue length (LLEN in Redis) once every 5 minutes and write it to the log in the database. Run a short script in a split second. In the same environment as the worker.
What is the best way to do it? Tried:

1. Each time to create a new container from the same image as the working one - it takes a noticeably long time
   
2. Do not delete the container, but restart it - it worked for a couple of days and stopped, with a pipe2 error
   
3. docker exec in the worker container. For some reason, it stopped running during rendering.