LazyInitRollingFileAppender.java

/**
 * RollingFileAppender with Lazy Initialization on GraalVM native image.
 */
public class LazyInitRollingFileAppender<E> extends ch.qos.logback.core.rolling.RollingFileAppender<E> {
    private boolean started = false;

    @Override
    public void start() {
        if (!inGraalImageBuildtimeCode()) {
            super.start();
            this.started = true;
        }

    }

    /**
     * This method is synchronized to avoid double start from doAppender().
     */
    protected void maybeStart() {
        lock.lock();
        try {
            if (!started)
                this.start();
        } finally {
            lock.unlock();
        }
    }

    @Override
    public void doAppend(E eventObject) {
        if (!inGraalImageBuildtimeCode()) {
            if (!started)
                maybeStart();

            super.doAppend(eventObject);
        }
    }

  
  //THE BELOW CODE CAN BE SUBSTITUTED BY ImageInfo.inImageBuildtimeCode() if you have it on your classpath
  
    private static final String PROPERTY_IMAGE_CODE_VALUE_BUILDTIME = "buildtime";
    private static final String PROPERTY_IMAGE_CODE_KEY = "org.graalvm.nativeimage.imagecode";
    /**
     * Returns true if (at the time of the call) code is executing in the context of Graal native image building
     * (e.g. in a static initializer of class that will be contained in the image).
     * Copy of graal code in org.graalvm.nativeimage.ImageInfo.inImageBuildtimeCode().
     * https://github.com/oracle/graal/blob/master/sdk/src/org.graalvm.nativeimage/src/org/graalvm/nativeimage/ImageInfo.java
     */
    private static boolean inGraalImageBuildtimeCode() {
        return PROPERTY_IMAGE_CODE_VALUE_BUILDTIME.equals(System.getProperty(PROPERTY_IMAGE_CODE_KEY));
    }

}