net.logstash.logback.pattern.EnhancedPropertyConverter Maven / Gradle / Ivy
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/*
* Copyright 2013-2022 the original author or authors.
*
* Licensed 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 net.logstash.logback.pattern;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import ch.qos.logback.classic.pattern.ClassicConverter;
import ch.qos.logback.classic.pattern.PropertyConverter;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.classic.spi.LoggerContextVO;
/**
* Variation of the Logback {@link PropertyConverter} with the option to specify a default
* value to use when the property does not exist instead of returning {@code null} as does
* the original Logback implementation.
*
* The default value is optional and can be specified using the :- operator as
* in Bash shell. For example, assuming the property "foo" is not defined, %property{foo:-bar}
* will return bar.
* If no optional value is declared, the converter returns an empty string instead of {@code null}
* if the property is not defined.
*
*
The property resolution mechanism is the same as the Logback implementation. The property is
* first looked up in the context associated with the logging event. If not found, the property is
* searched in the System environment.
*
*
* @author brenuart
*/
public class EnhancedPropertyConverter extends ClassicConverter {
/**
* Regex pattern used to extract the optional default value from the key name (split
* at the first :-).
*/
private static final Pattern PATTERN = Pattern.compile("(.+?):-(.*)");
/**
* The property name.
*/
private String propertyName;
/**
* The default value to use when the property is not defined.
*/
private String defaultValue = "";
public void start() {
String optStr = getFirstOption();
if (optStr != null) {
propertyName = optStr;
super.start();
}
if (propertyName == null) {
throw new IllegalStateException("Property name is not specified");
}
Matcher matcher = PATTERN.matcher(propertyName);
if (matcher.matches()) {
propertyName = matcher.group(1);
defaultValue = matcher.group(2);
}
}
@Override
public String convert(ILoggingEvent event) {
LoggerContextVO lcvo = event.getLoggerContextVO();
Map map = lcvo.getPropertyMap();
String val = map.get(propertyName);
if (val == null) {
val = System.getProperty(propertyName);
}
if (val == null) {
val = defaultValue;
}
return val;
}
}