Filtering

When you add Sentry to your app, you get a lot of valuable information about errors and performance. And lots of information is good -- as long as it's the right information, at a reasonable volume.

The Sentry SDKs have several configuration options to help you filter out events.

We also offer Inbound Filters to filter events in sentry.io. We recommend filtering at the client level though, because it removes the overhead of sending events you don't actually want. Learn more about the fields available in an event.

Filtering Error Events

To prevent certain errors from being reported to Sentry, use the BeforeSend or AddExceptionFilter configuration options, which allows you to evaluate whether to send an error or now. Alternatively, you can also control the behaviour by enabling, or disabling integrations.

Using BeforeSend

All Sentry SDKs support the BeforeSend callback method. Because it's called immediately before the event is sent to the server, this is your last chance to decide not to send data or to edit it. BeforeSend receives the event object as a parameter, which you can use to either modify the event’s data or drop it completely by returning null, based on custom logic and the data available on the event.

A Func<SentryEvent, Hint, SentryEvent?> can be used to mutate, discard (return null), or return a completely new event.

// Add this to the SDK initialization callback
options.SetBeforeSend((sentryEvent, hint) =>
{
    if (sentryEvent.Exception != null
      && sentryEvent.Exception.Message.Contains("Noisy Exception"))
    {
        return null; // Don't send this event to Sentry
    }

    sentryEvent.ServerName = null; // Never send Server Name to Sentry
    return sentryEvent;
});

Note also that breadcrumbs can be filtered, as discussed in our Breadcrumbs documentation.

Using AddExceptionFilter and AddExceptionFilterForType

The SDK also allows you to provide your own, custom exception filters. These have to inherit from IExceptionFilter

public class MyExceptionFilter : IExceptionFilter
{
    public bool Filter(Exception ex)
    {
        // TODO: Add your filtering logic
    }
}

and can then be provided to the options during initialization.

options.AddExceptionFilter(new MyExceptionFilter());

Exception types provided via AddExceptionFilterForType automatically get filtered and prevented from being set to Sentry.

options.AddExceptionFilterForType<MyCustomException>();

Filtering Transaction Events

To prevent certain transactions from being reported to Sentry, use the TracesSampler or BeforeSendTransaction configuration option, which allows you to provide a function to evaluate the current transaction and drop it if it's not one you want.

Using TracesSampler

Note: The TracesSampler and TracesSampleRate config options are mutually exclusive. If you define a TracesSampler to filter out certain transactions, you must also handle the case of non-filtered transactions by returning the rate at which you'd like them sampled.

In its simplest form, used just for filtering the transaction, it looks like this:

// Add this to the SDK initialization callback
options.TracesSampler = samplingContext =>
{
    if (/* make a decision based on `samplingContext` */) {
      // Drop this transaction, by setting its sample rate to 0%
      return 0;
    } else if (/* ... */) {
      // Override sample rate for other cases (replaces `options.TracesSampleRate`)
      return 0.1;
    }

    // Can return `null` to fallback to the rate configured by `options.TracesSampleRate`
    return null;
};

It also allows you to sample different transactions at different rates.

If the transaction currently being processed has a parent transaction (from an upstream service calling this service), the parent (upstream) sampling decision will always be included in the sampling context data, so that your TracesSampler can choose whether and when to inherit that decision. In most cases, inheritance is the right choice, to avoid breaking distributed traces. A broken trace will not include all your services. See Inheriting the parent sampling decision to learn more.

Learn more about configuring the sample rate.

Using BeforeSendTransaction

A Func<SentryTransaction, Hint, SentryTransaction?> can be used to update the transaction or drop it by returning null before it gets sent to Sentry. For example:

// Add this to the SDK initialization callback
options.SetBeforeSendTransaction((sentryTransaction, hint) =>
{
    // Modify the transaction
    if (sentryTransaction.Operation.Equals("http.server"))
    {
        return null; // Drop the transaction by returning null
    }

    return sentryTransaction;
});