log4j-core/src/main/java/org/apache/logging/log4j/core/appender/SocketAppender.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.logging.log4j.core.appender;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;

import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.helpers.Booleans;
import org.apache.logging.log4j.core.layout.SerializedLayout;
import org.apache.logging.log4j.core.net.AbstractSocketManager;
import org.apache.logging.log4j.core.net.Advertiser;
import org.apache.logging.log4j.core.net.DatagramSocketManager;
import org.apache.logging.log4j.core.net.Protocol;
import org.apache.logging.log4j.core.net.TCPSocketManager;
import org.apache.logging.log4j.util.EnglishEnums;

/**
 * An Appender that delivers events over socket connections. Supports both TCP and UDP.
 */
@Plugin(name = "Socket", category = "Core", elementType = "appender", printObject = true)
public class SocketAppender extends AbstractOutputStreamAppender<AbstractSocketManager> {
    private Object advertisement;
    private final Advertiser advertiser;

    protected SocketAppender(final String name, final Layout<? extends Serializable> layout, final Filter filter,
                             final AbstractSocketManager manager, final boolean ignoreExceptions,
                             final boolean immediateFlush, final Advertiser advertiser) {
        super(name, layout, filter, ignoreExceptions, immediateFlush, manager);
        if (advertiser != null) {
            final Map<String, String> configuration = new HashMap<String, String>(layout.getContentFormat());
            configuration.putAll(manager.getContentFormat());
            configuration.put("contentType", layout.getContentType());
            configuration.put("name", name);
            advertisement = advertiser.advertise(configuration);
        }
        this.advertiser = advertiser;
    }

    @Override
    public void stop() {
        super.stop();
        if (advertiser != null) {
            advertiser.unadvertise(advertisement);
        }
    }

    /**
     *
     * @param host The name of the host to connect to.
     * @param portNum The port to connect to on the target host.
     * @param protocol The Protocol to use.
     * @param delay The interval in which failed writes should be retried.
     * @param immediateFail True if the write should fail if no socket is immediately available.
     * @param name The name of the Appender.
     * @param immediateFlush "true" if data should be flushed on each write.
     * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
     *               they are propagated to the caller.
     * @param layout The layout to use (defaults to SerializedLayout).
     * @param filter The Filter or null.
     * @param advertise "true" if the appender configuration should be advertised, "false" otherwise.
     * @param config The Configuration
     * @return A SocketAppender.
     */
    @PluginFactory
    public static SocketAppender createAppender(
            @PluginAttribute("host") final String host,
            @PluginAttribute("port") final String portNum,
            @PluginAttribute("protocol") final String protocol,
            @PluginAttribute("reconnectionDelay") final String delay,
            @PluginAttribute("immediateFail") final String immediateFail,
            @PluginAttribute("name") final String name,
            @PluginAttribute("immediateFlush") final String immediateFlush,
            @PluginAttribute("ignoreExceptions") final String ignore,
            @PluginElement("Layout") Layout<? extends Serializable> layout,
            @PluginElement("Filters") final Filter filter,
            @PluginAttribute("advertise") final String advertise,
            @PluginConfiguration final Configuration config) {

        boolean isFlush = Booleans.parseBoolean(immediateFlush, true);
        final boolean isAdvertise = Boolean.parseBoolean(advertise);
        final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
        final boolean fail = Booleans.parseBoolean(immediateFail, true);
        final int reconnectDelay = AbstractAppender.parseInt(delay, 0);
        final int port = AbstractAppender.parseInt(portNum, 0);
        if (layout == null) {
            layout = SerializedLayout.createLayout();
        }

        if (name == null) {
            LOGGER.error("No name provided for SocketAppender");
            return null;
        }

        final Protocol p = EnglishEnums.valueOf(Protocol.class, protocol != null ? protocol : Protocol.TCP.name());
        if (p.equals(Protocol.UDP)) {
            isFlush = true;
        }

        final AbstractSocketManager manager = createSocketManager(p, host, port, reconnectDelay, fail, layout);
        if (manager == null) {
            return null;
        }

        return new SocketAppender(name, layout, filter, manager, ignoreExceptions, isFlush,
                isAdvertise ? config.getAdvertiser() : null);
    }

    protected static AbstractSocketManager createSocketManager(final Protocol p, final String host, final int port,
                                                               final int delay, final boolean immediateFail,
                                                               final Layout<? extends Serializable> layout) {
        switch (p) {
            case TCP:
                return TCPSocketManager.getSocketManager(host, port, delay, immediateFail, layout);
            case UDP:
                return DatagramSocketManager.getSocketManager(host, port, layout);
            default:
                return null;
        }
    }
}