Github user cakofony commented on a diff in the pull request:
https://github.com/apache/logging-log4j2/pull/206#discussion_r208727677
--- Diff:
log4j-redis/src/main/java/org/apache/logging/log4j/redis/appender/RedisAppender.java
---
@@ -0,0 +1,202 @@
+/*
+ * 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.redis.appender;
+
+import org.apache.logging.log4j.core.Appender;
+import org.apache.logging.log4j.core.Filter;
+import org.apache.logging.log4j.core.Layout;
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.appender.AbstractAppender;
+import org.apache.logging.log4j.core.config.Node;
+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.PluginBuilderFactory;
+import
org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
+import org.apache.logging.log4j.core.layout.AbstractStringLayout;
+
+import java.io.Serializable;
+import java.nio.charset.Charset;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Sends log events to a Redis Queue. All logs are appended Redis lists
via the RPUSH command.
+ */
+@Plugin(name = "Redis", category = Node.CATEGORY, elementType =
Appender.ELEMENT_TYPE, printObject = true)
+public final class RedisAppender extends AbstractAppender {
+
+ private RedisAppender(final String name, final Layout<? extends
Serializable> layout, final Filter filter,
+ final boolean ignoreExceptions, final
RedisManager manager) {
+ super(name, filter, layout, ignoreExceptions);
+ this.manager = Objects.requireNonNull(manager, "Redis Manager");
+ }
+
+ /**
+ * Builds RedisAppender instances.
+ * @param <B> The type to build
+ */
+ public static class Builder<B extends Builder<B>> extends
AbstractAppender.Builder<B>
+ implements
org.apache.logging.log4j.core.util.Builder<RedisAppender> {
+
+ @PluginAttribute("keys")
+ private String[] keys;
+
+ @PluginAttribute(value = "host")
+ @Required(message = "No Redis hostname provided")
+ private String host;
+
+ @PluginAttribute(value = "port")
+ private int port;
+
+ @PluginAttribute(value = "ssl")
+ private boolean ssl = false;
+
+ @SuppressWarnings("resource")
+ @Override
+ public RedisAppender build() {
+ return new RedisAppender(getName(), getLayout(), getFilter(),
isIgnoreExceptions(), getRedisManager());
+ }
+
+ public Charset getCharset() {
+ if (getLayout() instanceof AbstractStringLayout) {
+ return ((AbstractStringLayout) getLayout()).getCharset();
+ } else {
+ return Charset.defaultCharset();
+ }
+ }
+
+ String[] getKeys() {
+ return keys;
+ }
+
+ String getHost() {
+ return host;
+ }
+
+ boolean getSsl() {
+ return ssl;
+ }
+
+ int getPort() {
+ return port;
+ }
+
+ public B withKeys(final String key) {
+ this.keys = new String[]{key};
+ return asBuilder();
+ }
+
+ public B withKeys(final String[] keys) {
+ this.keys = keys;
+ return asBuilder();
+ }
+
+ public B withHost(final String host) {
+ this.host = host;
+ return asBuilder();
+ }
+
+ public B withPort(final int port) {
+ this.port = port;
+ return asBuilder();
+ }
+
+ public B withSsl(final boolean ssl) {
+ this.ssl = ssl;
+ return asBuilder();
+ }
+
+ RedisManager getRedisManager() {
+ return new RedisManager(
+ getConfiguration().getLoggerContext(),
+ getName(),
+ getKeys(),
+ getHost(),
+ getPort(),
+ getSsl(),
+ getCharset()
+ );
+ }
+ }
+
+ /**
+ * Creates a builder for a RedisAppender.
+ * @return a builder for a RedisAppender.
+ */
+ @PluginBuilderFactory
+ public static <B extends Builder<B>> B newBuilder() {
+ return new Builder<B>().asBuilder();
+ }
+
+ private final RedisManager manager;
+
+ @Override
+ public void append(final LogEvent event) {
+ if (event.getLoggerName() != null &&
event.getLoggerName().startsWith("org.apache.redis")) {
+ LOGGER.warn("Recursive logging from [{}] for appender [{}].",
event.getLoggerName(), getName());
+ } else {
+ try {
+ tryAppend(event);
+ } catch (final Exception e) {
+ error("Unable to write to Redis in appender [" + getName()
+ "]", event, e);
+ }
+ }
+ }
+
+ private void tryAppend(final LogEvent event) {
+ final Layout<? extends Serializable> layout = getLayout();
+ final byte[] header = layout.getHeader();
+ final byte[] body = layout.toByteArray(event);
+
+ int len = (header != null ? header.length : 0) + body.length;
+ byte[] data = new byte[len];
+ if (header != null) {
+ System.arraycopy(header, 0, data, 0, header.length);
--- End diff --
What is the use case for the header?
---
