apm-application-toolkit/apm-toolkit-log4j-2.x/src/main/java/org/apache/skywalking/apm/toolkit/log/log4j/v2/x/TraceIdConverter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */


package org.apache.skywalking.apm.toolkit.log.log4j.v2.x;

import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.pattern.ConverterKeys;
import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;

/**
 * {@link TraceIdConverter} is a log4j2 plugin, by annotation as {@link Plugin}.
 * It convert the pattern key: traceId.
 * Use '%traceId' in log4j2's config.
 * '%traceId' will output as TID:xxxx
 * <p>
 * Created by wusheng on 2016/12/7.
 */
@Plugin(name = "TraceIdConverter", category = "Converter")
@ConverterKeys({"traceId"})
public class TraceIdConverter extends LogEventPatternConverter {

    /**
     * Constructs an instance of LoggingEventPatternConverter.
     *
     * @param name name of converter.
     * @param style CSS style for output.
     */
    protected TraceIdConverter(String name, String style) {
        super(name, style);
    }

    public static TraceIdConverter newInstance(String[] options) {
        return new TraceIdConverter("traceId", "traceId");
    }

    @Override
    public void format(LogEvent event, StringBuilder toAppendTo) {
        Log4j2OutputAppender.append(toAppendTo);
    }
}