Log4j 1.x

The sentry-log4j library provides Log4j 1.x support for Sentry via an Appender that sends logged exceptions to Sentry.

The source can be found on Github.

Note: raven-log4j is no longer maintained. It is highly recommended that you migrate to sentry-log4j (which this documentation covers). If you are still using raven-log4j you can find the old documentation here.

Installation

Using Maven:

<dependency>
    <groupId>io.sentry</groupId>
    <artifactId>sentry-log4j</artifactId>
    <version>1.2.1</version>
</dependency>

Using Gradle:

compile 'io.sentry:sentry-log4j:1.2.1'

Using SBT:

libraryDependencies += "io.sentry" % "sentry-log4j" % "1.2.1"

For other dependency managers see the central Maven repository.

Usage

The following examples configure a ConsoleAppender that logs to standard out at the INFO level and a SentryAppender that logs to the Sentry server at the WARN level. The ConsoleAppender is only provided as an example of a non-Sentry appender that is set to a different logging threshold, like one you may already have in your project.

Example configuration using the log4j.properties format:

# Enable the Console and Sentry appenders
log4j.rootLogger=INFO, Console, Sentry

# Configure the Console appender
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=%d{HH:mm:ss.SSS} [%t] %-5p: %m%n

# Configure the Sentry appender, overriding the logging threshold to the WARN level
log4j.appender.Sentry=io.sentry.log4j.SentryAppender
log4j.appender.Sentry.threshold=WARN

Alternatively, using the log4j.xml format:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration debug="true"
    xmlns:log4j='http://jakarta.apache.org/log4j/'>

    <!-- Configure the Console appender -->
    <appender name="Console" class="org.apache.log4j.ConsoleAppender">
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern"
                   value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
        </layout>
    </appender>

    <!-- Configure the Sentry appender, overriding the logging threshold to the WARN level -->
    <appender name="Sentry" class="io.sentry.log4j.SentryAppender">
        <!-- Override the Sentry handler log level to WARN -->
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="levelMin" value="WARN" />
        </filter>
    </appender>

    <!-- Enable the Console and Sentry appenders, Console is provided as an example
         of a non-Sentry logger that is set to a different logging threshold -->
    <root level="INFO">
        <appender-ref ref="Console" />
        <appender-ref ref="Sentry" />
    </root>
</log4j:configuration>

Next, you’ll need to configure your DSN (client key) and optionally other values such as environment and release. See the configuration page for ways you can do this.

Additional Data

It’s possible to add extra data to events thanks to the MDC and the NDC systems provided by Log4j 1.x.

Mapped Tags

By default all MDC parameters are stored under the “Additional Data” tab in Sentry. By specifying the extratags option in your configuration you can choose which MDC keys to send as tags instead, which allows them to be used as filters within the Sentry UI.

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 additional data
    logger.error("This is a test");
}

In Practice

import org.apache.log4j.Logger;
import org.apache.log4j.MDC;
import org.apache.log4j.NDC;

public class MyClass {
    private static final Logger logger = Logger.getLogger(MyClass.class);

    void logSimpleMessage() {
        // This sends a simple event to Sentry
        logger.error("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.record(
            new BreadcrumbBuilder().setMessage("User made an action").build()
        );

        // This sends a simple event to Sentry
        logger.error("This is a test");
    }

    void logWithExtras() {
        // MDC extras
        MDC.put("extra_key", "extra_value");
        // NDC extras are sent under 'log4J-NDC'
        NDC.push("Extra_details");
        // This sends an event with extra data to Sentry
        logger.error("This is a test");
    }

    void logException() {
        try {
            unsafeMethod();
        } catch (Exception e) {
            // This sends an exception event to Sentry
            logger.error("Exception caught", e);
        }
    }

    void unsafeMethod() {
        throw new UnsupportedOperationException("You shouldn't call this!");
    }
}

Asynchronous Logging

Sentry uses asynchronous communication by default, and so it is unnecessary to use an AsyncAppender.