Use unix domain socket for Docker commands

standalone/app/build.gradle

@@ -3,6 +3,9 @@ plugins {
     id 'java-library'
 }
 
+sourceCompatibility = 17
+targetCompatibility = 17
+
 dependencies {
     implementation project(':api')
 

standalone/app/src/main/java/me/lucko/luckperms/standalone/app/LuckPermsApplication.java

@@ -37,7 +37,6 @@ import net.luckperms.api.LuckPerms;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -80,7 +79,7 @@ public class LuckPermsApplication implements AutoCloseable {
 
         List<String> arguments = Arrays.asList(args);
         if (arguments.contains("--docker")) {
-            this.dockerCommandSocket = DockerCommandSocket.createAndStart(3000, terminal);
+            this.dockerCommandSocket = DockerCommandSocket.createAndStart("/opt/luckperms/luckperms.sock", terminal);
             this.heartbeatHttpServer = HeartbeatHttpServer.createAndStart(3001, this.healthReporter);
         }
 
@@ -98,7 +97,7 @@ public class LuckPermsApplication implements AutoCloseable {
         if (this.dockerCommandSocket != null) {
             try {
                 this.dockerCommandSocket.close();
-            } catch (IOException e) {
+            } catch (Exception e) {
                 LOGGER.warn(e);
             }
         }

standalone/app/src/main/java/me/lucko/luckperms/standalone/app/utils/DockerCommandSocket.java

@@ -30,33 +30,43 @@ import org.apache.logging.log4j.Logger;
 
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStreamReader;
+import java.net.StandardProtocolFamily;
-import java.net.ServerSocket;
+import java.net.UnixDomainSocketAddress;
-import java.net.Socket;
+import java.nio.channels.Channels;
-import java.net.SocketException;
+import java.nio.channels.ClosedChannelException;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.function.Consumer;
 
 /**
- * Simple/dumb socket that listens for connections on a given port,
+ * Simple/dumb unix domain socket that listens for connections,
  * reads the input to a string, then executes it as a command.
  *
- * Combined with a small sh/nc program, this makes it easy to execute
+ * <p>Combined with a small sh/nc program, this makes it easy to execute
- * commands against a standalone instance of LP in a Docker container.
+ * commands against a standalone instance of LP in a Docker container.</p>
  */
-public class DockerCommandSocket extends ServerSocket implements Runnable {
+public class DockerCommandSocket implements Runnable, AutoCloseable {
     private static final Logger LOGGER = LogManager.getLogger(DockerCommandSocket.class);
 
-    public static DockerCommandSocket createAndStart(int port, TerminalInterface terminal) {
+    public static DockerCommandSocket createAndStart(String socketPath, TerminalInterface terminal) {
         DockerCommandSocket socket = null;
 
         try {
-            socket = new DockerCommandSocket(port, terminal::runCommand);
+            Path path = Paths.get(socketPath);
+            Files.deleteIfExists(path);
+
+            ServerSocketChannel channel = ServerSocketChannel.open(StandardProtocolFamily.UNIX);
+            channel.bind(UnixDomainSocketAddress.of(path));
+
+            socket = new DockerCommandSocket(channel, terminal::runCommand);
 
             Thread thread = new Thread(socket, "docker-command-socket");
             thread.setDaemon(true);
             thread.start();
-
-            LOGGER.info("Created Docker command socket on port " + port);
         } catch (Exception e) {
             LOGGER.error("Error starting docker command socket", e);
         }
@@ -64,30 +74,35 @@ public class DockerCommandSocket extends ServerSocket implements Runnable {
         return socket;
     }
 
+    private final ServerSocketChannel channel;
     private final Consumer<String> callback;
 
-    public DockerCommandSocket(int port, Consumer<String> callback) throws IOException {
+    public DockerCommandSocket(ServerSocketChannel channel, Consumer<String> callback) throws IOException {
-        super(port);
+        this.channel = channel;
         this.callback = callback;
     }
 
     @Override
     public void run() {
-        while (!isClosed()) {
+        while (this.channel.isOpen()) {
-            try (Socket socket = accept()) {
+            try (SocketChannel socket = this.channel.accept()) {
-                try (BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()))) {
+                try (BufferedReader reader = new BufferedReader(Channels.newReader(socket, StandardCharsets.UTF_8))) {
                     String cmd;
                     while ((cmd = reader.readLine()) != null) {
                         LOGGER.info("Executing command from Docker: " + cmd);
                         this.callback.accept(cmd);
                     }
                 }
+            } catch (ClosedChannelException e) {
+                // ignore
             } catch (IOException e) {
-                if (e instanceof SocketException && e.getMessage().equals("Socket closed")) {
-                    return;
-                }
                 LOGGER.error("Error processing input from the Docker socket", e);
             }
         }
     }
+
+    @Override
+    public void close() throws Exception {
+        this.channel.close();
+    }
 }

standalone/app/src/main/java/me/lucko/luckperms/standalone/app/utils/HeartbeatHttpServer.java

@@ -59,7 +59,7 @@ public class HeartbeatHttpServer implements HttpHandler, AutoCloseable {
 
         try {
             socket = new HeartbeatHttpServer(healthReporter, port);
-            LOGGER.info("Created Heartbeat HTTP server on port " + port);
+            LOGGER.info("Started healthcheck HTTP server on :" + port);
         } catch (Exception e) {
             LOGGER.error("Error starting Heartbeat HTTP server", e);
         }

standalone/build.gradle

@@ -2,6 +2,9 @@ plugins {
     id 'com.github.johnrengelman.shadow' version '7.0.0'
 }
 
+sourceCompatibility = 17
+targetCompatibility = 17
+
 dependencies {
     implementation project(':common')
     compileOnly project(':common:loader-utils')

standalone/docker/Dockerfile

@@ -4,7 +4,7 @@ RUN apk add --no-cache openjdk17 netcat-openbsd
 # create a simple 'send' command that will allow users
 # to run, for example: docker exec <container> send lp info
 RUN printf '#!/bin/sh\n\
-echo "$@" | nc -N localhost 3000\n' >> /usr/bin/send && chmod 777 /usr/bin/send
+echo "$@" | nc -NU /opt/luckperms/luckperms.sock\n' >> /usr/bin/send && chmod 777 /usr/bin/send
 
 # setup user
 RUN addgroup -S app && adduser -S -G app app

standalone/loader/build.gradle

@@ -11,6 +11,9 @@ dependencies {
     implementation project(':standalone:app')
 }
 
+sourceCompatibility = 17
+targetCompatibility = 17
+
 application {
     mainClass = 'me.lucko.luckperms.standalone.loader.StandaloneLoader'
 }