Advanced Usage
Learn about adding extra data using the MDC system provided by SLF4j.
You can add extra data to events using the MDC system for any SLF4J implementation supporting MDC that's on a classpath, (for example Logback, Log4j2, JUL).
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-jdk14</artifactId>
<version>1.7.30</version>
</dependency>
By default all MDC parameters are stored under the “MDC” tab in Sentry.
import java.util.logging.Level;
import org.slf4j.MDC;
void logWithExtras() {
// MDC extras
MDC.put("Environment", "Development");
MDC.put("OS", "Linux");
// This sends an event where the Environment and OS MDC values are set as MDC entries
logger.log(Level.SEVERE, "This is a test");
}
Note that MDC manages data on a per-thread basis, and that a child thread does not automatically inherit MDC properties from its parent.
import io.sentry.Sentry;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.slf4j.MDC;
public class MyClass {
private final Logger logger = Logger.getLogger(MyClass.class.getName());
void logSimpleMessage() {
// This sends a simple event to Sentry
logger.severe("This is a test");
}
void logWithBreadcrumbs() {
// Record a breadcrumb that will be sent with the next event(s),
// by default the last 100 breadcrumbs are kept.
Sentry.addBreadcrumb("User made an action");
// Log entries below `minimumEventLevel` and above or equal to `minimumBreadcrumbLevel`
// are recorded as breadcrumbs
logger.info("User made another action");
// This sends a simple event to Sentry
logger.severe("This is a test");
}
void logWithExtras() {
// MDC extras
MDC.put("extra_key", "extra_value");
// This sends an event with extra data to Sentry
logger.severe("This is a test");
}
void logException() {
try {
unsafeMethod();
} catch (Exception e) {
// This sends an exception event to Sentry
logger.log(Level.SEVERE, "Exception caught", e);
}
}
void unsafeMethod() {
throw new UnsupportedOperationException("You shouldn't call this!");
}
}
Starting with Sentry version 6.0.0 and up, you can define a list of MDC tags that will be viewable as Tags in the Sentry UI. MDC Tags not in this list will be viewable as Context Data. To define tags, add a context-tags entry with the tags as comma-separated items to the sentry.properties file.
dsn=https://examplePublicKey@o0.ingest.sentry.io/0
context-tags=userId,requestId
When you call MDC.put("userId", "myUserId") with the above configuration in place, the userId will show up as a tag on the event in the Sentry UI.
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").