Removes ipc port file after shutdown, reduced so timeout for rmi clients

main/launcher/src/main/java/org/cryptomator/launcher/InterProcessCommunicator.java

@@ -9,6 +9,7 @@ import java.io.Closeable;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.ServerSocket;
+import java.net.Socket;
 import java.nio.ByteBuffer;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
@@ -56,11 +57,9 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 	// visible for testing
 	static InterProcessCommunicator start(Path portFilePath, InterProcessCommunicationProtocol endpoint) throws IOException {
 		System.setProperty("java.rmi.server.hostname", "localhost");
-		// try to connect to existing server:
-		int port = readPort(portFilePath);
-		LOG.debug("Connecting to running process on TCP port {}...", port);
 		try {
-			ClientCommunicator client = new ClientCommunicator(port);
+			// try to connect to existing server:
+			ClientCommunicator client = new ClientCommunicator(portFilePath);
 			LOG.trace("Connected to running process.");
 			return client;
 		} catch (ConnectException | ConnectIOException | NotBoundException e) {
@@ -70,8 +69,7 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 
 		// spawn a new server:
 		LOG.trace("Spawning new server...");
-		ServerCommunicator server = new ServerCommunicator(endpoint);
-		writePort(portFilePath, server.getPort());
+		ServerCommunicator server = new ServerCommunicator(endpoint, portFilePath);
 		LOG.debug("Server listening on port {}.", server.getPort());
 		return server;
 	}
@@ -98,12 +96,30 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 
 		private final IpcProtocolRemote remote;
 
-		private ClientCommunicator(int port) throws ConnectException, NotBoundException, RemoteException {
-			if (port == 0) {
-				throw new ConnectException("Can not connect to port 0.");
+		private ClientCommunicator(Path portFilePath) throws ConnectException, NotBoundException, RemoteException {
+			if (Files.notExists(portFilePath)) {
+				throw new ConnectException("No IPC port file.");
+			}
+			try {
+				int port = ClientCommunicator.readPort(portFilePath);
+				LOG.debug("Connecting to port {}...");
+				Registry registry = LocateRegistry.getRegistry("localhost", port, new ClientSocketFactory());
+				this.remote = (IpcProtocolRemote) registry.lookup(RMI_NAME);
+			} catch (IOException e) {
+				throw new ConnectException("Error reading IPC port file.");
+			}
+		}
+
+		private static int readPort(Path portFilePath) throws IOException {
+			ByteBuffer buf = ByteBuffer.allocate(Integer.BYTES);
+			try (ReadableByteChannel ch = Files.newByteChannel(portFilePath, StandardOpenOption.READ)) {
+				if (ch.read(buf) == Integer.BYTES) {
+					buf.flip();
+					return buf.getInt();
+				} else {
+					throw new IOException("Invalid IPC port file.");
+				}
 			}
-			Registry registry = LocateRegistry.getRegistry("localhost", port);
-			this.remote = (IpcProtocolRemote) registry.lookup(RMI_NAME);
 		}
 
 		@Override
@@ -132,8 +148,9 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 		private final ServerSocket socket;
 		private final Registry registry;
 		private final IpcProtocolRemoteImpl remote;
+		private final Path portFilePath;
 
-		private ServerCommunicator(InterProcessCommunicationProtocol delegate) throws IOException {
+		private ServerCommunicator(InterProcessCommunicationProtocol delegate, Path portFilePath) throws IOException {
 			this.socket = new ServerSocket(0, Byte.MAX_VALUE, InetAddress.getByName("localhost"));
 			RMIClientSocketFactory csf = RMISocketFactory.getDefaultSocketFactory();
 			SingletonServerSocketFactory ssf = new SingletonServerSocketFactory(socket);
@@ -141,6 +158,20 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 			this.remote = new IpcProtocolRemoteImpl(delegate);
 			UnicastRemoteObject.exportObject(remote, 0);
 			registry.rebind(RMI_NAME, remote);
+			this.portFilePath = portFilePath;
+			ServerCommunicator.writePort(portFilePath, socket.getLocalPort());
+		}
+
+		private static void writePort(Path portFilePath, int port) throws IOException {
+			ByteBuffer buf = ByteBuffer.allocate(Integer.BYTES);
+			buf.putInt(port);
+			buf.flip();
+			MoreFiles.createParentDirectories(portFilePath);
+			try (WritableByteChannel ch = Files.newByteChannel(portFilePath, StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)) {
+				if (ch.write(buf) != Integer.BYTES) {
+					throw new IOException("Did not write expected number of bytes.");
+				}
+			}
 		}
 
 		@Override
@@ -163,6 +194,7 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 				registry.unbind(RMI_NAME);
 				UnicastRemoteObject.unexportObject(remote, true);
 				socket.close();
+				Files.deleteIfExists(portFilePath);
 				LOG.debug("Server shut down.");
 			} catch (NotBoundException | IOException e) {
 				LOG.warn("Failed to close IPC Server.", e);
@@ -211,31 +243,18 @@ abstract class InterProcessCommunicator implements InterProcessCommunicationProt
 
 	}
 
-	private static int readPort(Path path) throws IOException {
-		if (Files.notExists(path)) {
-			return 0;
-		}
-		ByteBuffer buf = ByteBuffer.allocate(Integer.BYTES);
-		try (ReadableByteChannel ch = Files.newByteChannel(path, StandardOpenOption.READ)) {
-			if (ch.read(buf) == Integer.BYTES) {
-				buf.flip();
-				return buf.getInt();
-			} else {
-				return 0;
-			}
-		}
-	}
+	/**
+	 * Creates client sockets with short timeouts.
+	 */
+	private static class ClientSocketFactory implements RMIClientSocketFactory {
 
-	private static void writePort(Path path, int port) throws IOException {
-		ByteBuffer buf = ByteBuffer.allocate(Integer.BYTES);
-		buf.putInt(port);
-		buf.flip();
-		MoreFiles.createParentDirectories(path);
-		try (WritableByteChannel ch = Files.newByteChannel(path, StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)) {
-			if (ch.write(buf) != Integer.BYTES) {
-				throw new IOException("Did not write expected number of bytes.");
-			}
+		@Override
+		public Socket createSocket(String host, int port) throws IOException {
+			Socket socket = new Socket(host, port);
+			socket.setSoTimeout(1000); // 1s
+			return socket;
 		}
+
 	}
 
 }