Set Up Tracing

With tracing, Sentry tracks your software performance, measuring metrics like throughput and latency, and displaying the impact of errors across multiple systems. Sentry captures distributed traces consisting of transactions and spans, which measure individual services and individual operations within those services. Learn more about our model in Distributed Tracing.

Requirements

Tracing is available for the Sentry Java SDK version ≥ 4.0.

Enable Tracing

To automatically send traces, you must configure SentryTracingFilter in web.xml for Servlet applications configured with XML, or WebApplicationInitializer for Servlet applications configured with Java code:

import io.sentry.spring.tracing.SentryTracingFilter;
import javax.servlet.Filter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
  // ...
  @Override
  protected Filter[] getServletFilters() {
    return new Filter[] {new SentryTracingFilter()};
  }
}

Configure

First, enable tracing and configure the sample rate for transactions. Set the sample rate for your transactions by either:

• Setting a uniform sample rate for all transactions using the tracesSampleRate option in your SDK config to a number between 0 and 1. (For example, to send 20% of transactions, set tracesSampleRate to 0.2.)
• Controlling the sample rate based on the transaction itself and the context in which it's captured, by providing a function to the tracesSampler config option.

The two options are meant to be mutually exclusive. If you set both, tracesSampler will take precedence.

Or alternatively:

Configure sample rate in sentry.properties:

# Set traces_sample_rate to 1.0 to capture 100%
# of transactions for tracing.
# We recommend adjusting this value in production.
traces-sample-rate=1.0

Or through providing a bean of type SentryOptions#TracesSamplerCallback:

import io.sentry.SentryOptions.TracesSamplerCallback;
import io.sentry.SamplingContext;
import org.springframework.stereotype.Component;

@Component
class CustomTracesSamplerCallback implements TracesSamplerCallback {
  @Override
  public Double sample(SamplingContext context) {
    CustomSamplingContext customSamplingContext = context.getCustomSamplingContext();
    if (customSamplingContext != null) {
      HttpServletRequest request = (HttpServletRequest) customSamplingContext.get("request");
      // return a number between 0 and 1 or null (to fallback to configured value)
    } else {
      // return a number between 0 and 1 or null (to fallback to configured value)
    }
  }
}

Without sampling, automatically-captured transactions can add up quickly. The Spring integration, for example, will send a transaction for every request made to the server.

Learn more about tracing options, how to use the tracesSampler function, or how to sample transactions.

Verify

Verify that tracing is working correctly by using our automatic instrumentation or by starting and finishing a transaction using custom instrumentation.

While you're testing, set tracesSampleRate to 1.0, as that ensures that every transaction will be sent to Sentry. Once testing is complete, you may want to set a lower tracesSampleRate value, or switch to using tracesSampler to selectively sample and filter your transactions, based on contextual data.

Next Steps