Conserving Sentry Transactions by Ignoring Laravel Routes

Yet another case of trying to find an answer to a very particular problem, coming up empty, solving it myself, and posting about it for future generations.

Update 2023-04-01#anchor

Thanks to Michi Hoffmann, this is now even easier to manage with a built in ignore_transactions configuration option now available as of release 3.17.0 of sentry-php!

Now, instead of using the before_send_transaction config I swapped to using ignore_transactions and my code changed to the following:

'ignore_transactions' => ['/_debugbar', '/monitoring', '/pleaseignoreme'],

Below is the original post for posterity, but with the addition above that solution is no longer necessary.

The Problem#anchor

I have a couple Laravel PHP routes that are triggered quite often, both are very specific to other site monitoring (is the site down?) and session management (am I still logged in?). These being utility routes that don’t serve a user-facing purpose, I don’t need any additional logging details about them from Sentry.

Can I prevent the transaction from being sent to Sentry before it even leaves my server? I tried searching terms like “sentry laravel ignore route” and “sentry control transactions from PHP” to no avail so I got to work.

The Solution#anchor

In my searches, I did find this helpful documentation for before_send_transaction specifically for Laravel. It’s an optional addition to the /config/sentry.php configuration. In it, you can define any logic you want to return null in preferred situations. This null return will lead to the event being discarded. Bingo!

Here’s the code I worked up.

'before_send_transaction' => function (
    \Sentry\Event $transaction
): ?\Sentry\Event {
    $ignore = ['_debugbar', 'monitoring', 'pleaseignoreme'];
    $request = $transaction->getRequest();
    $check = array_filter($ignore, function ($url) use ($request) {
        if (stripos($request['url'], $url) !== false) {
            return true;
        }
    });

    if (count($check) > 0) {
        return null;
    }

    return $transaction;
},

Here’s what it’s doing:

• $ignore is the array of URL key terms I want to ignore, this is all you need to edit. Add any URL segments that you’d prefer not to be logged by Sentry and you good to go
• $request is the request details coming from the packaged $transaction generated by Sentry. In it is the full URL that we use to test against
• $check was my method of iterating through the ignore list and checking for a match. This filters the $ignore array down to just matches.
• We then see if the count of $check is greater than zero, if so then one of the routes matched and we want to return null to ignore this transaction. Otherwise, return as normal.

Closure Alternative#anchor

Shout out to Alex Bouma for also noting in this Github Gist how to avoid using a closure (as I had in the solution above) because it makes php artisan config:cache no longer work. Something I hadn’t noticed until after I had the above solution in place.

If you choose to continue using before_send_transaction and need config caching, give a class a try!

That’s it!#anchor

Pretty simple, but it took a bit of digging through documentation to find before_send_transaction and through the Sentry package to see what $transaction contained so I’m hoping to spare the next dev that bit of trouble.

Onward and upward! 🚀