BAEL1731 Log4j2 Plugins

logging-modules/log4j2/src/main/java/com/baeldung/logging/log4j2/plugins/DockerPatternConverter.java

@@ -0,0 +1,30 @@
+package com.baeldung.logging.log4j2.plugins;
+
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.config.plugins.Plugin;
+import org.apache.logging.log4j.core.pattern.ConverterKeys;
+import org.apache.logging.log4j.core.pattern.LogEventPatternConverter;
+import org.apache.logging.log4j.core.pattern.PatternConverter;
+
+@Plugin(name = "DockerPatternConverter", category = PatternConverter.CATEGORY)
+@ConverterKeys({"docker", "container"})
+public class DockerPatternConverter extends LogEventPatternConverter {
+
+    private DockerPatternConverter(String[] options) {
+        super("Docker", "docker");
+    }
+
+    public static DockerPatternConverter newInstance(String[] options) {
+        return new DockerPatternConverter(options);
+    }
+
+    @Override
+    public void format(LogEvent event, StringBuilder toAppendTo) {
+        toAppendTo.append(dockerContainer());
+    }
+
+    private String dockerContainer() {
+        //get docker container ID inside which application is running here
+        return "container-1";
+    }
+}

logging-modules/log4j2/src/main/java/com/baeldung/logging/log4j2/plugins/KafkaAppender.java

@@ -0,0 +1,133 @@
+package com.baeldung.logging.log4j2.plugins;
+
+import org.apache.logging.log4j.core.Core;
+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.plugins.Plugin;
+import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
+import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
+import org.apache.logging.log4j.core.config.plugins.PluginElement;
+import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
+
+import java.io.Serializable;
+
+@Plugin(name = "Kafka2", category = Core.CATEGORY_NAME)
+public class KafkaAppender extends AbstractAppender {
+
+    @PluginBuilderFactory
+    public static Builder newBuilder() {
+        return new Builder();
+    }
+
+    public static class Builder implements org.apache.logging.log4j.core.util.Builder<KafkaAppender> {
+
+        @PluginBuilderAttribute("name")
+        @Required
+        private String name;
+
+        @PluginBuilderAttribute("ip")
+        private String ipAddress;
+
+        @PluginBuilderAttribute("port")
+        private int port;
+
+        @PluginBuilderAttribute("topic")
+        private String topic;
+
+        @PluginBuilderAttribute("partition")
+        private String partition;
+
+        @PluginElement("Layout")
+        private Layout<? extends Serializable> layout;
+
+        @PluginElement("Filter")
+        private Filter filter;
+
+        public Layout<? extends Serializable> getLayout() {
+            return layout;
+        }
+
+        public Builder setLayout(Layout<? extends Serializable> layout) {
+            this.layout = layout;
+            return this;
+        }
+
+        public Filter getFilter() {
+            return filter;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public Builder setName(String name) {
+            this.name = name;
+            return this;
+        }
+
+        public Builder setFilter(Filter filter) {
+            this.filter = filter;
+            return this;
+        }
+
+        public String getIpAddress() {
+            return ipAddress;
+        }
+
+        public Builder setIpAddress(String ipAddress) {
+            this.ipAddress = ipAddress;
+            return this;
+        }
+
+        public int getPort() {
+            return port;
+        }
+
+        public Builder setPort(int port) {
+            this.port = port;
+            return this;
+        }
+
+        public String getTopic() {
+            return topic;
+        }
+
+        public Builder setTopic(String topic) {
+            this.topic = topic;
+            return this;
+        }
+
+        public String getPartition() {
+            return partition;
+        }
+
+        public Builder setPartition(String partition) {
+            this.partition = partition;
+            return this;
+        }
+
+        @Override
+        public KafkaAppender build() {
+            return new KafkaAppender(getName(), getFilter(), getLayout(), true, new KafkaBroker(ipAddress, port, topic, partition));
+        }
+    }
+
+    private KafkaBroker broker;
+
+    private KafkaAppender(String name, Filter filter, Layout<? extends Serializable> layout, boolean ignoreExceptions, KafkaBroker broker) {
+        super(name, filter, layout, ignoreExceptions);
+        this.broker = broker;
+    }
+
+    @Override
+    public void append(LogEvent event) {
+
+        connectAndSendToKafka(broker, event);
+    }
+
+    private void connectAndSendToKafka(KafkaBroker broker, LogEvent event) {
+        //send to Kafka
+    }
+}

logging-modules/log4j2/src/main/java/com/baeldung/logging/log4j2/plugins/KafkaBroker.java

@@ -0,0 +1,38 @@
+package com.baeldung.logging.log4j2.plugins;
+
+import java.io.Serializable;
+
+public class KafkaBroker implements Serializable {
+
+    private final String ipAddress;
+    private final int port;
+
+    public KafkaBroker(String ipAddress, int port, String topic, String partition) {
+        this.ipAddress = ipAddress;
+        this.port = port;
+        this.topic = topic;
+        this.partition = partition;
+    }
+
+    public String getTopic() {
+        return topic;
+    }
+
+    public String getPartition() {
+        return partition;
+    }
+
+    private final String topic;
+    private final String partition;
+
+
+    public String getIpAddress() {
+        return ipAddress;
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+
+}

logging-modules/log4j2/src/main/java/com/baeldung/logging/log4j2/plugins/KafkaLookup.java

@@ -0,0 +1,24 @@
+package com.baeldung.logging.log4j2.plugins;
+
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.config.plugins.Plugin;
+import org.apache.logging.log4j.core.lookup.StrLookup;
+
+@Plugin(name = "kafka", category = StrLookup.CATEGORY)
+public class KafkaLookup implements StrLookup {
+
+    @Override
+    public String lookup(String key) {
+        return getFromKafka(key);
+    }
+
+    @Override
+    public String lookup(LogEvent event, String key) {
+        return getFromKafka(key);
+    }
+
+    private String getFromKafka(String topicName) {
+        //kafka search logic should go here
+        return "topic1-p1";
+    }
+}

logging-modules/log4j2/src/test/resources/log4j2.xml

@@ -50,6 +50,12 @@
             </Policies>
         </RollingFile>
         <MapAppender name="MapAppender"/>
+        <Console name="DockerConsoleLogger" target="SYSTEM_OUT">
+            <PatternLayout pattern="%pid %docker" />
+        </Console>
+        <Kafka2 name="KafkaLogger" ip ="127.0.0.1" port="9010" topic="log" partition="p-1">
+            <PatternLayout pattern="%pid%style{%message}{red}%n" />
+        </Kafka2>
     </Appenders>
     <Loggers>
         <Logger name="CONSOLE_PATTERN_APPENDER_MARKER" level="TRACE"
@@ -80,6 +86,9 @@
             additivity="false">
             <AppenderRef ref="ConsoleJSONAppender" />
         </Logger>
+        <Logger name="com.baeldung.logging.log4j2.plugins" level="INFO">
+            <AppenderRef ref="KafkaLogger" />
+        </Logger>
         <Root level="DEBUG">
             <AppenderRef ref="ConsoleAppender" />
             <AppenderRef ref="MapAppender" />