Logback extras

Extras and helpers for Logback logging.

Installation

Maven

<dependency>
    <groupId>com.bisnode.logging</groupId>
    <artifactId>logback-extras</artifactId>
    <version>1.0.0</version>
</dependency>

Gradle

implementation group: 'com.bisnode.logging', name: 'logback-extras', version: '1.0.0'

Duplicate message cooldown filter

The duplicate message cooldown filter resembles the Logback included DuplicateMessageFilter but instead of suppressing duplicate messages forever after hitting the configured threshold it does so only during the configured cooldown period, and after that resumes logging the duplicate until the threshold is hit once again.

When dealing with misconfigured or poorly implemented logging, this saves your logs from getting flooded with duplicate messages, while still logging some of them in short bursts for a chance to be seen and possibly fixed.

This filter is similar to the "burst filter" sometimes requested for Logback and since some time back available in Log4j, but is more conservative in that it only filters duplicates as those are per definition noise, while meaningful logging may be suppressed by a more general burst filter.

Usage

In your Logback XML configuration, add a turboFilter configuration pointing to the DuplicateMessageCooldownFilter:

<configuration>

    <turboFilter class="com.bisnode.logging.DuplicateMessageCooldownFilter">
        <cooldownInitiationThreshold>10</cooldownInitiationThreshold>
        <cooldownDurationSeconds>60</cooldownDurationSeconds>
        <acceptableDuplicateFrequencyPerSecond>1</acceptableDuplicateFrequencyPerSecond>
    </turboFilter>

</configuration>

Configuration options

• cooldownInitiationThreshold: The number of duplicate messages that should trigger a cooldown period. Default 20.
• cooldownDurationSeconds: Duration of the cooldown period, i.e. how long duplicate messages should be suppressed. Default 30.
• acceptableDuplicateFrequencyPerSecond: Acceptable duplicate frequency per second. This number will be subtracted from the duplicate counter every second. Default 1.

Dependencies

This package does not introduce additional dependencies.