You can try all of the examples by downloading this repository https://github.com/rk4xxicom/symfony-prometheus-example (you will need docker-compose to run it though). But not just any kind of traffic, we (ideally!) would want to distinguish between different kinds of traffic.
Suppose you have a number of accounts in different stages and you want to see how that number changes over time — when do you get an influx of new accounts, how it is correlated with CPU load etc.
If you need to monitor such metrics, but do not want to rewrite the application code because of it, you can try to extract the data from the logs.
You can see the exact data that is being stored by connecting to Redis: Since it is working now, we once again need to tell Prometheus what to scrape (the full config can be found here).