Switch to log4j2 logging

.gitignore

@@ -118,3 +118,6 @@ gradle-app.setting
 
 
 # End of https://www.gitignore.io/api/java,gradle,intellij
+
+# Other trash
+logs/

build.gradle

@@ -25,6 +25,8 @@ dependencies {
     compile "io.netty:netty-transport-native-epoll:${nettyVersion}"
     compile "io.netty:netty-transport-native-epoll:${nettyVersion}:linux-x86_64"
     compile 'net.kyori:text:1.12-1.5.0'
+    compile 'org.apache.logging.log4j:log4j-api:2.11.0'
+    compile 'org.apache.logging.log4j:log4j-core:2.11.0'
     testCompile 'org.junit.jupiter:junit-jupiter-api:5.3.0-M1'
     testCompile 'org.junit.jupiter:junit-jupiter-engine:5.3.0-M1'
 }

src/main/java/com/velocitypowered/network/ConnectionManager.java

@@ -11,6 +11,8 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftVarintFrameDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftVarintLengthEncoder;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.LogManager;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ServerBootstrap;
 import io.netty.channel.Channel;
@@ -45,6 +47,8 @@ import static com.velocitypowered.network.Connections.MINECRAFT_ENCODER;
 import static com.velocitypowered.network.Connections.READ_TIMEOUT;
 
 public final class ConnectionManager {
+    private static final org.apache.logging.log4j.Logger logger = LogManager.getLogger(ConnectionManager.class);
+
     private static final String DISABLE_EPOLL_PROPERTY = "velocity.connection.disable-epoll";
     private static final boolean DISABLE_EPOLL = Boolean.getBoolean(DISABLE_EPOLL_PROPERTY);
     private final Set<Channel> endpoints = new HashSet<>();
@@ -71,12 +75,12 @@ public final class ConnectionManager {
 
     private void logChannelInformation(final boolean epoll) {
         final StringBuilder sb = new StringBuilder();
-        sb.append("Channel type: ");
+        sb.append("Using channel type ");
         sb.append(epoll ? "epoll": "nio");
         if(DISABLE_EPOLL) {
             sb.append(String.format(" - epoll explicitly disabled using -D%s=true", DISABLE_EPOLL_PROPERTY));
         }
-        System.out.println(sb.toString()); // TODO: move to logger
+        logger.info(sb.toString()); // TODO: move to logger
     }
 
     public void bind(final InetSocketAddress address) {
@@ -109,10 +113,9 @@ public final class ConnectionManager {
                     final Channel channel = future.channel();
                     if (future.isSuccess()) {
                         this.endpoints.add(channel);
-                        System.out.println("Listening on " + channel.localAddress()); // TODO: move to logger
+                        logger.info("Listening on {}", channel.localAddress());
                     } else {
-                        System.out.println("Can't bind to " + channel.localAddress()); // TODO: move to logger
-                        future.cause().printStackTrace();
+                        logger.error("Can't bind to {}", address, future.cause());
                     }
                 });
     }
@@ -126,11 +129,10 @@ public final class ConnectionManager {
     public void shutdown() {
         for (final Channel endpoint : this.endpoints) {
             try {
-                System.out.println(String.format("Closing endpoint %s", endpoint.localAddress())); // TODO: move to logger
+                logger.info("Closing endpoint {}", endpoint.localAddress());
                 endpoint.close().sync();
             } catch (final InterruptedException e) {
-                System.err.println("Interrupted whilst closing endpoint"); // TODO: move to logger
-                e.printStackTrace();
+                logger.info("Interrupted whilst closing endpoint", e);
             }
         }
     }

src/main/java/com/velocitypowered/proxy/connection/client/LoginSessionHandler.java

@@ -12,6 +12,8 @@ import com.velocitypowered.proxy.connection.backend.ServerConnection;
 import com.velocitypowered.proxy.data.ServerInfo;
 import com.velocitypowered.proxy.util.EncryptionUtils;
 import com.velocitypowered.proxy.util.UuidUtils;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 import java.net.InetSocketAddress;
 import java.net.URL;
@@ -21,6 +23,8 @@ import java.util.Arrays;
 import java.util.concurrent.ThreadLocalRandom;
 
 public class LoginSessionHandler implements MinecraftSessionHandler {
+    private static final Logger logger = LogManager.getLogger(LoginSessionHandler.class);
+
     private static final String MOJANG_SERVER_AUTH_URL =
             "https://sessionserver.mojang.com/session/minecraft/hasJoined?username=%s&serverId=%s&ip=%s";
 
@@ -71,8 +75,7 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
                         handleSuccessfulLogin(profile);
                     }, inbound.getChannel().eventLoop())
                     .exceptionally(exception -> {
-                        System.out.println("Can't enable encryption");
-                        exception.printStackTrace();
+                        logger.error("Unable to enable encryption", exception);
                         inbound.close();
                         return null;
                     });

src/main/resources/log4j2.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="warn">
+    <Appenders>
+        <Console name="Console" target="SYSTEM_OUT">
+            <PatternLayout pattern="[%d{HH:mm:ss} %level]: %msg%n"/>
+        </Console>
+        <RollingRandomAccessFile name="File" fileName="logs/latest.log" filePattern="logs/%d{yyyy-MM-dd}-%i.log.gz"
+                                 immediateFlush="false">
+            <PatternLayout pattern="[%d{HH:mm:ss} %level]: %msg%n"/>
+            <Policies>
+                <TimeBasedTriggeringPolicy/>
+                <OnStartupTriggeringPolicy/>
+            </Policies>
+        </RollingRandomAccessFile>
+    </Appenders>
+
+    <Loggers>
+        <Root level="info">
+            <AppenderRef ref="Console"/>
+            <AppenderRef ref="File"/>
+        </Root>
+    </Loggers>
+</Configuration>