Logback / Logstash / Fluentd

build.gradle

dependencies {
    implementation 'net.logstash.logback:logstash-logback-encoder:7.2'
    implementation 'org.fluentd:fluent-logger:0.3.4'
    implementation 'com.sndyuk:logback-more-appenders:1.5.6'
}

logback-spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
Spring Boot Logback configurations:
https://github.com/spring-projects/spring-boot/tree/main/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/logback

STASH properties
stashFile     = logging.stash.file (context)
              | STASH_FILE (env)
              | stashPath/stashFilename.log
stashPath     = logging.stash.path (context)
              | STASH_PATH (env)
              | '.' (default)
stashFilename = logging.stash.filename (context)
              | STASH_FILENAME (env)
              | appName
appName       = spring.application.name (context)
              | APP_NAME (env)
              | 'application' (default)
-->
<configuration>
    <include resource="org/springframework/boot/logging/logback/defaults.xml"/>
    <include resource="org/springframework/boot/logging/logback/console-appender.xml"/>
    <springProperty
            name="appName"
            scope="context"
            source="spring.application.name"
            defaultValue="${APP_NAME:-application}"
    />

    <!-- Stash for Logstash -->
    <springProperty
            name="stashPath"
            scope="context"
            source="logging.stash.path"
            defaultValue="${STASH_PATH:-.}"
    />
    <springProperty
            name="stashFilename"
            scope="context"
            source="logging.stash.filename"
            defaultValue="${STASH_FILENAME:-${appName}}"
    />
    <springProperty
            name="stashFile"
            scope="context"
            source="logging.stash.file"
            defaultValue="${STASH_FILE:-${stashPath}/${stashFilename}.log}"
    />
    <property name="STASH_FILE" value="${stashFile}"/>
    <appender name="STASH" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="net.logstash.logback.encoder.LogstashEncoder"/>
        <file>${STASH_FILE}</file>
        <append>true</append>
        <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
            <fileNamePattern>
                ${LOGBACK_ROLLINGPOLICY_FILE_NAME_PATTERN:-${STASH_FILE}.%d{yyyy-MM-dd}.%i.gz}
            </fileNamePattern>
            <cleanHistoryOnStart>
                ${LOGBACK_ROLLINGPOLICY_CLEAN_HISTORY_ON_START:-false}
            </cleanHistoryOnStart>
            <maxFileSize>
                ${LOGBACK_ROLLINGPOLICY_MAX_FILE_SIZE:-10MB}
            </maxFileSize>
            <totalSizeCap>
                ${LOGBACK_ROLLINGPOLICY_TOTAL_SIZE_CAP:-0}
            </totalSizeCap>
            <maxHistory>
                ${LOGBACK_ROLLINGPOLICY_MAX_HISTORY:-7}
            </maxHistory>
        </rollingPolicy>
    </appender>

    <!-- Fluent for Fluentd -->
    <property name="FLUENTD_HOST" value="${FLUENTD_HOST:-localhost}"/>
    <property name="FLUENTD_PORT" value="${FLUENTD_PORT:-24224}"/>
    <appender name="FLUENT" class="ch.qos.logback.more.appenders.DataFluentAppender">
        <!-- Check tag and label fluentd info: https://docs.fluentd.org/configuration/config-file -->
        <tag>microservice.helloworld.access</tag>
        <label>normal</label>
        <remoteHost>${FLUENTD_HOST}</remoteHost>
        <port>${FLUENTD_PORT}</port>
    </appender>

    <!-- Root -->
    <root level="INFO">
        <appender-ref ref="CONSOLE"/>
        <appender-ref ref="STASH"/>
        <appender-ref ref="FLUENT"/>
    </root>
</configuration>