Profiling Commands

In the dev environment on our site, we get the web debug toolbar. And more importantly, the profiler, which is packed full of goodies. Even if our app is entirely an API, we can go directly to /_profiler to check out the profiler for any API request.

This is one of Symfony's killer features. And for 6.4, Symfony contributor Jules Pietri wondered: why can't we have this for console commands?

And now, we do! It's meant to be used for your custom console commands that might be big or complex, but we can also use it with core commands.

Triggering a Profile: --profile

Spin over and run:

php bin/console debug:container

If you run a normal command, it won't activate the profiler system and collect info. To trigger that, you need to run the command with --profile.

php bin/console debug:container --profile

Nothing looks different, but that did just activate the profiler... which collected info and stored it... somewhere. But... it's not obvious where we can go to see it!

So what you really want to do is pass -v:

php bin/console debug:container --profile -v

Now, at the bottom, it includes the unique token that can be used in the profiler URL. But, really, be lazier and run with -vvv:

php bin/console debug:container --profile -vvv

This time, we get a link - and even details about memory and time. I'll click the link and... it doesn't work. It's almost the right URL, but my terminal doesn't know what port my local web server is using. Copy that token, then... go to the profiler for any request, paste the token in the URL and... so cool!

Exploring the Profiler

We see info about the command, the input, output... and most importantly, we have the normal profiler sections! One interesting one is events: showing the actual events that were dispatched and the listeners for each one. These are totally different from the events that are triggered during a request, so it's cool to see them.

Now, you probably noticed that most of the profiler sections are grayed out. But if you did render a Twig template... or make an HTTP request or make a database query, these would be activated.

Even with this simple command, we unlock the performance section. Not a lot here in this case, but it makes me feel dangerous.

So that's it! Another, cool, well-thought-out feature. I'd love to see how people end up using this.

Ok, on to our final topic: let's experiment with one of Symfony's best new components: Scheduler.