logback-config-rfc-27 - SKILL.md Agent Skill

name: logback-config-rfc-27 description: > RFC-27 compliant static Logback configuration for Java services. Covers logback.xml structure, appenders, encoders, and deployment-specific configuration. Use when setting up or reviewing logging configuration in Java services. compatibility: Java projects using Spring Boot with Logback metadata: version: "1.0.0" technology: java category: observability tags: - java - logging - rfc-27 - logback - configuration

Logback Configuration (RFC-27)

RFC-27 compliant static Logback configuration for Java services.

When to use this skill

Setting up logging configuration for new Java services
Reviewing or updating logback.xml configuration
Configuring environment-specific logging
Setting up log file rotation and retention
Configuring appenders for different outputs (console, file, JSON)

Skill Contents

Available Resources

📚 references/ - Detailed documentation

configuration patterns

Quick Start

1. Create logback-spring.xml

Place in src/main/resources/logback-spring.xml:

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" scanPeriod="30 seconds">
    <include resource="org/springframework/boot/logging/logback/defaults.xml"/>

    <!-- Console appender for local development -->
    <springProfile name="local">
        <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
            <encoder>
                <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
            </encoder>
        </appender>
        <root level="INFO">
            <appender-ref ref="CONSOLE"/>
        </root>
    </springProfile>

    <!-- JSON appender for production -->
    <springProfile name="!local">
        <appender name="JSON" class="ch.qos.logback.core.ConsoleAppender">
            <encoder class="net.logstash.logback.encoder.LogstashEncoder"/>
        </appender>
        <root level="INFO">
            <appender-ref ref="JSON"/>
        </root>
    </springProfile>
</configuration>

2. Do NOT Commit logback.xml to Git

Per RFC-27, logback.xml should NOT be in version control. Use logback-spring.xml instead, which supports Spring profiles.

Configuration Structure

Required Elements

Element	Purpose
`<configuration>`	Root element with optional scan attributes
`<appender>`	Defines output destination
`<encoder>`	Formats log messages
`<root>`	Default logging level

Spring Profile Integration

Use <springProfile> to apply configuration conditionally:

<springProfile name="production">
    <!-- Production-specific config -->
</springProfile>

<springProfile name="!production">
    <!-- Non-production config -->
</springProfile>

Appender Types

Appender	Use Case
`ConsoleAppender`	Standard output (container logs)
`RollingFileAppender`	File with rotation
`AsyncAppender`	Non-blocking wrapper

Console Appender (Production)

<appender name="JSON" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="net.logstash.logback.encoder.LogstashEncoder">
        <includeMdcKeyName>traceId</includeMdcKeyName>
        <includeMdcKeyName>spanId</includeMdcKeyName>
    </encoder>
</appender>

Environment Configuration

Log Levels per Environment

Environment	Root Level	Notes
`local`	DEBUG	Verbose for development
`development`	INFO	Standard logging
`staging`	INFO	Match production
`production`	INFO	Minimize noise

Logger Overrides

<!-- Reduce noise from specific libraries -->
<logger name="org.apache.kafka" level="WARN"/>
<logger name="org.springframework.web" level="INFO"/>
<logger name="com.bitso" level="DEBUG"/>

References

Reference	Description
references/configuration-patterns.md	Detailed configuration examples

Related Rules

java-structured-logs - Structured logging standards (RFC-34)

Related Skills

Skill	Purpose
structured-logs-rfc-34	Structured logging format
dynamic-loglevel-rfc-27	Runtime log level control