org.log4mongo.MongoDbPatternLayoutAppender Maven / Gradle / Ivy
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/*
* Copyright (C) 2010 Robert Stewart ([email protected])
*
* 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 org.log4mongo;
import org.apache.log4j.spi.ErrorCode;
import org.apache.log4j.spi.LoggingEvent;
import com.mongodb.DBObject;
import com.mongodb.MongoException;
import com.mongodb.util.JSON;
/**
* A Log4J Appender that uses a PatternLayout to write log events into a MongoDB database.
*
* The conversion pattern specifies the format of a JSON document. The document can contain
* sub-documents and the elements can be strings or arrays.
*
* For some Log4J appenders (especially file appenders) blank space padding is often used to get
* fields in adjacent rows to line up. For example, %-5p is often used to make all log levels the
* same width in characters. Since each value is stored in a separate property in the document, it
* usually doesn't make sense to use blank space padding with MongoDbPatternLayoutAppender.
*
* The appender does not create any indexes on the data that's stored. If query performance
* is required, indexes must be created externally (e.g., in the mongo shell or an external
* reporting application).
*
* @author Robert Stewart ([email protected])
* @see Log4J
* Appender Interface
* @see MongoDB
*/
public class MongoDbPatternLayoutAppender extends MongoDbAppender {
@Override
public boolean requiresLayout() {
return (true);
}
/**
* Inserts a BSON representation of a LoggingEvent into a MongoDB collection. A PatternLayout is
* used to format a JSON document containing data available in the LoggingEvent and, optionally,
* additional data returned by custom PatternConverters.
*
* The format of the JSON document is specified in the .layout.ConversionPattern property.
*
* @param loggingEvent
* The LoggingEvent that will be formatted and stored in MongoDB
*/
@Override
protected void append(final LoggingEvent loggingEvent) {
if (isInitialized()) {
DBObject bson = null;
String json = layout.format(loggingEvent);
if (json.length() > 0) {
Object obj = JSON.parse(json);
if (obj instanceof DBObject) {
bson = (DBObject) obj;
}
}
if (bson != null) {
try {
getCollection().insert(bson);
} catch (MongoException e) {
errorHandler.error("Failed to insert document to MongoDB", e,
ErrorCode.WRITE_FAILURE);
}
}
}
}
}