Layout System

/**
 * Interface for creating Logback layouts
 * @param <E> The type of log event
 */
public interface LayoutFactory<E extends DeferredProcessingAware> {
    /**
     * Creates a {@link PatternLayoutBase} of type E
     * @param context the Logback context
     * @param timeZone the TimeZone
     * @return a new {@link PatternLayoutBase}
     */
    PatternLayoutBase<E> build(LoggerContext context, TimeZone timeZone);
}

/**
 * Jackson-discoverable layout factory for building Logback layouts
 * @param <E> The type of log event
 */
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type")
public interface DiscoverableLayoutFactory<E extends DeferredProcessingAware> extends Discoverable {
    /**
     * Creates a {@link LayoutBase} of type E
     * @param context the Logback context
     * @param timeZone the TimeZone
     * @return a new {@link LayoutBase}
     */
    LayoutBase<E> build(LoggerContext context, TimeZone timeZone);
}

/**
 * Factory for creating DropwizardLayout instances
 */
public class DropwizardLayoutFactory implements LayoutFactory<ILoggingEvent> {
    /**
     * Build a DropwizardLayout instance
     * @param context the Logback logger context
     * @param timeZone the timezone for timestamp formatting
     * @return configured DropwizardLayout
     */
    @Override
    public PatternLayoutBase<ILoggingEvent> build(LoggerContext context, TimeZone timeZone);
}

/**
 * Default Dropwizard log layout with custom converters
 */
public class DropwizardLayout extends PatternLayout {
    /**
     * Default constructor that sets up custom converters and formatting
     */
    public DropwizardLayout();
    
    /**
     * Get the default Dropwizard log pattern
     * @return the default pattern string
     */
    public static String getDefaultPattern();
    
    /**
     * Set up custom throwable converters
     */
    private void setupCustomConverters();
}

DropwizardLayoutFactory layoutFactory = new DropwizardLayoutFactory();
LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();
TimeZone timeZone = TimeZone.getTimeZone("UTC");
Layout<ILoggingEvent> layout = layoutFactory.build(context, timeZone);

// Or create directly
DropwizardLayout layout = new DropwizardLayout();
layout.setContext(context);
layout.start();

/**
 * Prefixes stack traces with configurable prefix
 */
public class PrefixedThrowableProxyConverter extends ThrowableProxyConverter {
    public static final String PATTERN = "([\\da-f]{8}-[\\da-f]{4}-[\\da-f]{4}-[\\da-f]{4}-[\\da-f]{12})";
    public static final String PREFIX = "! ";
    
    /**
     * Convert throwable to formatted string with prefix
     * @param event the logging event containing the throwable
     * @return formatted string with prefixed lines
     */
    @Override
    public String convert(ILoggingEvent event);
}

/**
 * Extended throwable converter with packaging data and prefix
 */
public class PrefixedExtendedThrowableProxyConverter extends PrefixedThrowableProxyConverter {
    /**
     * Add extra packaging data to the output
     * @param builder the StringBuilder to append to
     * @param step the stack trace element proxy containing packaging information
     */
    @Override
    protected void extraData(StringBuilder builder, StackTraceElementProxy step);
}

/**
 * Root-cause-first throwable converter with prefixing
 */
public class PrefixedRootCauseFirstThrowableProxyConverter extends RootCauseFirstThrowableProxyConverter {
    /**
     * Convert throwable proxy to formatted string showing root cause first with prefix
     * @param tp the throwable proxy to convert
     * @return formatted string with root cause first and prefixed lines
     */
    @Override
    protected String throwableProxyToString(IThrowableProxy tp);
}

// Register custom converters in a custom layout
public class CustomLayout extends PatternLayout {
    @Override
    public void start() {
        // Register the custom converters
        getContext().putProperty("CONVERTER_CLASS_dwEx", 
            PrefixedThrowableProxyConverter.class.getName());
        getContext().putProperty("CONVERTER_CLASS_dwREx", 
            PrefixedRootCauseFirstThrowableProxyConverter.class.getName());
        getContext().putProperty("CONVERTER_CLASS_dwXEx", 
            PrefixedExtendedThrowableProxyConverter.class.getName());
        
        super.start();
    }
}

%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n%dwEx

%cyan(%d{HH:mm:ss.SSS}) %gray([%thread]) %highlight(%-5level) %magenta(%logger{36}) - %msg%n%dwEx

{"timestamp":"%d{yyyy-MM-dd'T'HH:mm:ss.SSS'Z'}","thread":"%thread","level":"%-5level","logger":"%logger","message":"%msg","exception":"%dwEx"}%n

%msg%n%dwEx

%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} [%X{requestId}] - %msg%n%dwXEx