Add ignoreTransactions and ignoreErrors

[smeubank]

Background:

To further simplfiy ignoring certain events from being sent to sentry, it is also suggested to provide ignoreTransactions and ignoreErrors

More info here develop docs updated: https://develop.sentry.dev/sdk/features/#event-sampling

• ignoreErrors
• ignoreTransactions
• SDK docs

[mattjohnsonpint]

For ignoreErrors, the .NET SDK already has exception filters, which I believe is the same concept.

Examples:

SentrySdk.Init(options =>
{
    options.AddExceptionFilterForType<FileNotFoundException>();
});

Or:

SentrySdk.Init(options =>
{
    options.AddExceptionFilter(new MyExceptionFilter());
});

public class MyExceptionFilter : IExceptionFilter
{
    public bool Filter(Exception ex) => ex.Message.Contains("something");
}

We could add another IgnoreErrors property, but I'm not sure that it would add any additional value. Comparing with other SDKs:

• Java has ignoredExceptionsForType, which would be like calling our AddExceptionFilter multiple times.
• JavaScript has ignoreErrors that takes an array of strings or regex to match against the message. This might be confusing in .NET because we would usually want a strong match by the type, rather than a substring of the message. (Especially since message strings are often translated for localization.)

[mattjohnsonpint]

We don't have any ignoreTransactions equivalent though (other than filtering them out in BeforeSendTransaction). I presume it should be similar to the JavaScript version.

[bitsandfoxes]

The SDK functionally supports these via

• Filtering of errors via SetBeforeSend

  sentry-dotnet/src/Sentry/SentryOptions.cs

  Line 438 in 7fd6f20

  public void SetBeforeSend(Func<SentryEvent, Hint, SentryEvent?> beforeSend)

• Filtering of transactions via SetBeforeTransaction

  sentry-dotnet/src/Sentry/SentryOptions.cs

  Line 464 in 7fd6f20

  public void SetBeforeSendTransaction(Func<SentryTransaction, Hint, SentryTransaction?> beforeSendTransaction)

• Sampling/filtering of transactions via TracesSampler function

  sentry-dotnet/src/Sentry/SentryOptions.cs

  Line 898 in 7fd6f20

  public Func<TransactionSamplingContext, double?>? TracesSampler { get; set; }

[ericsampson]

It feels like in the docs, AddExceptionFilterForType should be mentioned in the Filtering section. Right now it's in an an odd place in the docs

[bitsandfoxes]

It feels like in the docs, AddExceptionFilterForType should be mentioned in the Filtering section. Right now it's in an an odd place in the docs

Good callout! Thanks!

[ericsampson]

This could be a dumb question, but does that exception filter affect Transactions in any way, or just Errors?

[jamescrosswell]

does that exception filter affect Transactions in any way, or just Errors?

Just error events:

sentry-dotnet/src/Sentry/SentryClient.cs

Lines 270 to 277 in 37eb4a5

	var filteredExceptions = ApplyExceptionFilters(@event.Exception);
	if (filteredExceptions?.Count > 0)
	{
	_options.ClientReportRecorder.RecordDiscardedEvent(DiscardReason.EventProcessor, DataCategory.Error);
	_options.LogInfo("Event was dropped by one or more exception filters for exception(s): {0}",
	string.Join(", ", filteredExceptions.Select(e => e.GetType()).Distinct()));
	return SentryId.Empty;
	}