org.graylog2.gelfclient.encoder.GelfMessageJsonEncoder Maven / Gradle / Ivy

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/*
 * Copyright 2014 TORCH GmbH
 *
 * 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.graylog2.gelfclient.encoder;

import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;
import org.graylog2.gelfclient.GelfMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.ByteArrayOutputStream;
import java.util.List;
import java.util.Map;

/**
 * A Netty channel handler encoding {@link GelfMessage} into valid JSON according to the
 * GELF specification.
 */
@ChannelHandler.Sharable
public class GelfMessageJsonEncoder extends MessageToMessageEncoder {
    private static final Logger LOG = LoggerFactory.getLogger(GelfMessageJsonEncoder.class);
    private final JsonFactory jsonFactory;

    /**
     * Creates a new instance of this channel handler with the default {@link com.fasterxml.jackson.core.JsonFactory}.
     */
    public GelfMessageJsonEncoder() {
        this(new JsonFactory());
    }

    /**
     * Creates a new instance of this channel handler with the given {@link com.fasterxml.jackson.core.JsonFactory}.
     *
     * @param jsonFactory the Jackson {@link com.fasterxml.jackson.core.JsonFactory} to use for constructing a GELF message payload
     */
    public GelfMessageJsonEncoder(final JsonFactory jsonFactory) {
        this.jsonFactory = jsonFactory;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        super.exceptionCaught(ctx, cause);
        LOG.error("JSON encoding error", cause);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void encode(ChannelHandlerContext ctx, GelfMessage message, List