co.elastic.logging.log4j.MdcAccess Maven / Gradle / Ivy
/*-
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* Java ECS logging
* %%
* Copyright (C) 2019 - 2020 Elastic and contributors
* %%
* Licensed to Elasticsearch B.V. under one or more contributor
* license agreements. See the NOTICE file distributed with
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* 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
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*/
package co.elastic.logging.log4j;
import org.apache.log4j.MDC;
import org.apache.log4j.pattern.LogEvent;
import org.apache.log4j.spi.LoggingEvent;
import java.util.Collections;
import java.util.Map;
public interface MdcAccess {
Map getMDC(LoggingEvent event);
class Resolver {
public static MdcAccess resolve() {
try {
LoggingEvent.class.getMethod("getProperties");
return (MdcAccess) Class.forName("co.elastic.logging.log4j.MdcAccess$GetPropertiesCapable").getEnumConstants()[0];
} catch (Exception ignore) {
} catch (LinkageError ignore) {
}
return ForLegacyLog4j.INSTANCE;
}
}
/**
* For log4j versions {@code >=} 1.2.15 that have the {@link LogEvent#getProperties()} method
*/
enum GetPropertiesCapable implements MdcAccess {
INSTANCE;
@Override
public Map getMDC(LoggingEvent event) {
if (Thread.currentThread().getName().equals(event.getThreadName())) {
// avoids copying the properties if the appender is synchronous
return MDC.getContext();
}
return event.getProperties();
}
}
/**
* Fallback for log4j versions {@code <} 1.2.15
*/
enum ForLegacyLog4j implements MdcAccess {
INSTANCE;
@Override
public Map getMDC(LoggingEvent event) {
if (Thread.currentThread().getName().equals(event.getThreadName())) {
return MDC.getContext();
}
// can't access MDC in async appenders
return Collections.emptyMap();
}
}
}