bug: NettyApiServer.start() blocks indefinitely on bind without timeout

[sfloess]

Bug Description

The start() method uses .sync() on the bind operation, which blocks indefinitely if the bind fails or hangs. This can cause the application startup to freeze.

Location

jplatform-rest-api-netty/src/main/java/org/flossware/jplatform/rest/netty/NettyApiServer.java:124

Problematic Code

ChannelFuture future = bootstrap.bind(config.getHost(), config.getPort()).sync();
serverChannel = future.channel();
running = true;

Impact

• Indefinite hang: If bind operation stalls, application startup freezes
• No timeout: No way to detect and recover from hang
• Thread blocked: Startup thread blocked indefinitely
• No feedback: User doesn't know why startup is stuck
• Resource leak: EventLoopGroups created but server not running

Example

// Port already in use or firewall blocking
NettyApiServer server = new NettyApiServer(config);
server.start();
// bind() operation queued but never completes
// sync() blocks forever
// Application appears to hang during startup
// No exception, no timeout, no log message
// EventLoopGroups consuming resources

Proposed Fix

@Override
public void start() throws ServerStartupException {
    if (running) {
        return;
    }

    try {
        bossGroup = new NioEventLoopGroup(config.getBossThreads());
        workerGroup = config.getWorkerThreads() > 0
            ? new NioEventLoopGroup(config.getWorkerThreads())
            : new NioEventLoopGroup();

        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup)
            .channel(NioServerSocketChannel.class)
            .childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel ch) {
                    ChannelPipeline pipeline = ch.pipeline();
                    pipeline.addLast(new HttpServerCodec());
                    pipeline.addLast(new HttpObjectAggregator(config.getMaxContentLength()));
                    pipeline.addLast(new HttpRequestHandler(routes));
                }
            })
            .option(ChannelOption.SO_BACKLOG, config.getBacklog())
            .childOption(ChannelOption.SO_KEEPALIVE, config.isKeepAlive());

        // Bind with timeout
        ChannelFuture bindFuture = bootstrap.bind(config.getHost(), config.getPort());
        
        // Wait for bind to complete with timeout
        if (!bindFuture.await(30, TimeUnit.SECONDS)) {
            // Timeout waiting for bind
            throw new ServerStartupException(
                "Timeout waiting for server to bind to " + config.getHost() + ":" + config.getPort(),
                config.getPort(),
                null
            );
        }
        
        // Check if bind was successful
        if (!bindFuture.isSuccess()) {
            throw new ServerStartupException(
                "Failed to bind server to " + config.getHost() + ":" + config.getPort(),
                config.getPort(),
                bindFuture.cause()
            );
        }
        
        serverChannel = bindFuture.channel();
        running = true;

        logger.info("Netty API server started on {}:{}", config.getHost(), config.getPort());
        
    } catch (ServerStartupException e) {
        // Cleanup resources on failure
        cleanupResources();
        throw e;
    } catch (Exception e) {
        cleanupResources();
        logger.error("Failed to start Netty API server", e);
        throw new ServerStartupException("Failed to start server", config.getPort(), e);
    }
}

private void cleanupResources() {
    if (workerGroup != null) {
        workerGroup.shutdownGracefully();
    }
    if (bossGroup != null) {
        bossGroup.shutdownGracefully();
    }
}

[sfloess]

Fixed in recent commits