Server Unreachable When Using AutoServer Plugin

[TropicSnowJPR]

There appears to be an issue with starting the server when using the latest version of the AutoServer plugin. The server initially starts normally and completes the standard startup process. However, after startup:

• The server cannot be pinged from any local server.
• Pinging the proxy is unsuccessful.
• The Minecraft client does not display the server correctly. The client shows a very long ping time that eventually times out.

The behavior suggests that the server is online but not reachable, either locally or remotely. No errors or warnings are logged during this process.

If I remove the plugin, the server works perfectly. I have attached the configuration file for reference.

checkForUpdates = true
maintenanceInterval = 5
startRateLimit = 60


[messages]
prefix = ""
starting = "<green>%serverName%<gray> is Offline. Server is starting you will moved as soon as the server is ready.<reset>"
failed = "<dark_red>Unable to connect you to %serverName%.<reset>"
notify = "<gray>You will be moved to <green>%serverName%<gray> in 5 seconds...<reset>"
startRateLimitExceeded = "<dark_red>Please wait a bit before doing this!<reset>"


[servers]

[servers.creative]
workingDirectory = "/home/minecraft/Creative"
start = "screen -DmS Creative bash start.sh"
stop = "screen -p 0 -S Creative -X stuff \"stop\r\""
startupDelay = 30
shutdownDelay = 5
autoShutdownDelay = 900

[servers.lobby]
workingDirectory = "/home/minecraft/Lobby"
start = "screen -DmS Lobby bash start.sh"
stop = "screen -p 0 -S Lobby -X stuff \"stop\r\""
startupDelay = 30
shutdownDelay = 5
autoShutdownDelay = 0

[servers.moddedcreatesmp]
workingDirectory = "/home/minecraft/Modded_CreateSMP"
start = "screen -DmS Modded-CreateSMP bash run.sh"
stop = "screen -p 0 -S Modded-CreateSMP -X stuff \"stop\r\""
startupDelay = 60
shutdownDelay = 5
autoShutdownDelay = 900

[servers.survival]
workingDirectory = "/home/minecraft/Survival"
start = "screen -DmS Survival bash start.sh"
stop = "screen -p 0 -S Survival -X stuff \"stop\r\""
startupDelay = 90
shutdownDelay = 20
autoShutdownDelay = 900

[servers.moddedatm10sky]
workingDirectory = "/home/minecraft/Modded_ATM10Sky"
start = "screen -DmS Modded-ATM10Sky bash run.sh"
stop = "screen -p 0 -S Modded-ATM10Sky -X stuff \"stop\r\""
startupDelay = 120
shutdownDelay = 20
autoShutdownDelay = 900

[servers.bedwars]
workingDirectory = "/home/minecraft/Bedwars"
start = "screen -DmS Bedwars bash start.sh"
stop = "screen -p 0 -S Bedwars -X stuff \"stop\r\""
startupDelay = 60
shutdownDelay = 10
autoShutdownDelay = 900


[logging]
level = "DEBUG"

[Artimba]

I am encountering an issue similar to this trying to connect to an ATM10 server behind my velocity proxy. I am able to connect to it without Autostart, but autostart continually fails to ping it. Every other server that aren't as packet heavy are fine and function with/without autostart fine, its specifically linked to ATM for me so far.

Running this off Windows, seeing you encountering the same thing on the bash side of things is a little demoralizing.

[Artimba]

At least for my case, I did some digging and expanded the logging a bit and managed to identify

CorruptedFrameException: Packet sent for class com.velocitypowered.proxy.protocol.packet.StatusResponsePacket was too big (expected 5700 bytes, got 5744 bytes)

ATM is sending too large of packets for Autostart/Velocity's pingServer method. I added in a fallback ping method that allows me to connect to my servers again.

[TropicSnowJPR]

Yeah, bumping the packet size limit or adding a fallback ping would probably solve it. Would be good if that got adjusted in an update.

[TropicSnowJPR]

Actually, I just noticed my modded servers were never even online for my server, so I’m not sure how the packet size issue would happen in my case. Might be something else entirely.

[TropicSnowJPR]

Also i tried running is with debug like u did and the were no errors is said is started but the veloocity server does not respond after that. the console normaly has as > were you can type commands but niether the symbol is there nor commands work and a there is no "listening on ........." message so im pretty sure its a different issue to yours @Artimba

[Artimba]

Also i tried running is with debug like u did and the were no errors is said is started but the veloocity server does not respond after that. the console normaly has as > were you can type commands but niether the symbol is there nor commands work and a there is no "listening on ........." message so im pretty sure its a different issue to yours @Artimba

I didn't get any logs from setting the debug flag, I only got it by adding more print statements to the ping and server methods within the project itself sadly. Am not totally sure if we were encountering the same issue, Id only expect mine to happen when trying to connect to a heavily modded server like ATM

[TropicSnowJPR]

Yesterday I also looked into the code and got a fallback method working by using it when the default one fails. I think my fallback ping also allows me to handle large, heavily modded server responses, since I made a raw ping method over a TCP socket — the Netty-based ping from Velocity seems to be limited. So I think I got it working for my server at least. I can share what I did if you’re interested @Artimba.

[TropicSnowJPR]

Here the changes i made:

---

ServerManager.java

private CompletableFuture<Boolean> pingServer(RegisteredServer server, int pingTimeout) {
    String serverName = server.getServerInfo().getName();
    logger.debug("Pinging server {}...", serverName);

    CompletableFuture<Boolean> velocityPing = server.ping().orTimeout(pingTimeout,TimeUnit.MILLISECONDS).thenApply(serverPing-> {
        logger.debug("ping success {} is {}online{}", serverName, AnsiColors.GREEN, AnsiColors.RESET);
        if (!getServerStatus(server).isStopping()) {
            // only update to running if not in a state of stopping
            getServerStatus(server).setStatus(ServerStatus.Status.RUNNING);
        }
        return true;
    });

    return velocityPing.handle((res, ex) -> {
        if (ex == null) {
            return CompletableFuture.completedFuture(true);
        }

        // Velocity ping failed; try raw ping
        logger.debug("velocity ping failed for {}: {} - trying raw socket ping", serverName, ex.getMessage());
        return rawPingServer(server, pingTimeout).thenApply(success -> {
            if (success) {
                logger.debug("raw ping success {} is {}online{}", serverName, AnsiColors.GREEN, AnsiColors.RESET);
                if (!getServerStatus(server).isStopping()) {
                    getServerStatus(server).setStatus(ServerStatus.Status.RUNNING);
                }
                return true;
            } else {
                logger.debug("raw ping failed {} is {}offline{}", serverName, AnsiColors.RED, AnsiColors.RESET);
                if (!getServerStatus(server).isStarting()) {
                    getServerStatus(server).setStatus(ServerStatus.Status.STOPPED);
                }
                return false;
            }
        });
    }).thenCompose(cf -> cf);
}

private CompletableFuture<Boolean> rawPingServer(RegisteredServer server, int pingTimeout) {
    return CompletableFuture.supplyAsync(() -> {
        InetSocketAddress addr = server.getServerInfo().getAddress();
            try (Socket socket = new Socket()) {
                socket.connect(new InetSocketAddress(addr.getAddress(), addr.getPort()), Math.max(1, pingTimeout));
                socket.setSoTimeout(Math.max(1, pingTimeout));

                DataOutputStream out = new DataOutputStream(socket.getOutputStream());
                DataInputStream in = new DataInputStream(socket.getInputStream());

                // Build Handshake packet (packet id 0 for handshake)
                ByteArrayOutputStream handshakeBuffer = new ByteArrayOutputStream();
                DataOutputStream handshake = new DataOutputStream(handshakeBuffer);
                writeVarInt(handshake, 0); // packet id = 0 (handshake)
                writeVarInt(handshake, 754); // protocol version (use a modern protocol - 754 is common)
                writeString(handshake, addr.getHostString()); // server address
                handshake.writeShort(addr.getPort()); // server port
                writeVarInt(handshake, 1); // next state = status

                byte[] hbytes = handshakeBuffer.toByteArray();
                writeVarInt(out, hbytes.length);
                out.write(hbytes);

                // Send Status Request (packet id 0, no payload)
                writeVarInt(out, 1); // length
                writeVarInt(out, 0); // packet id 0 = status request

                // Read response length
                int length = readVarInt(in);
                if (length <= 0) return false;
                byte[] data = new byte[length];
                in.readFully(data);
                DataInputStream dataIn = new DataInputStream(new java.io.ByteArrayInputStream(data));

                int packetId = readVarInt(dataIn);
                if (packetId != 0) return false; // expected status response

                String json = readString(dataIn);
                // If we reach here we received a valid status JSON response
                return json != null && !json.isEmpty();
            } catch (IOException e) {
                logger.debug("rawPingServer IO error for {}: {}", server.getServerInfo().getName(), e.getMessage());
                return false;
            }
        });
    }
}


private static void writeVarInt(DataOutputStream out, int value) throws IOException {
    while ((value & 0xFFFFFF80) != 0L) {
        out.writeByte((value & 0x7F) | 0x80);
        value >>>= 7;
    }
    out.writeByte(value & 0x7F);
}

private static int readVarInt(DataInputStream in) throws IOException {
    int numRead = 0;
    int result = 0;
    byte read;
    do {
        read = in.readByte();
        int value = (read & 0b01111111);
        result |= (value << (7 * numRead));

        numRead++;
        if (numRead > 5) {
            throw new IOException("VarInt is too big");
        }
    } while ((read & 0b10000000) != 0);

    return result;
}

private static void writeString(DataOutputStream out, String s) throws IOException {
    byte[] bytes = s.getBytes(StandardCharsets.UTF_8);
    writeVarInt(out, bytes.length);
    out.write(bytes);
}

private static String readString(DataInputStream in) throws IOException {
    int len = readVarInt(in);
    if (len < 0) return null;
    byte[] bytes = new byte[len];
    in.readFully(bytes);
    return new String(bytes, StandardCharsets.UTF_8);
}

---

LocalStartable.java

private String runCommand(String path, String command, Boolean preserveQuotes) throws RuntimeException {
    CommandRunner.CommandResult commandResult = CommandRunner.runCommand(path, command, preserveQuotes);

    // Start streaming output from the process into the plugin logger and keep a tail buffer
    final LinkedList<String> tail = new LinkedList<>();
    final int maxTail = 200;
    if (commandResult.getProcess() != null) {
        Thread t = new Thread(() -> {
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(commandResult.getProcess().getInputStream()))) {
                String line;
                while ((line = reader.readLine()) != null) {
                    // keep tail
                    synchronized (tail) {
                        tail.add(line);
                        if (tail.size() > maxTail) tail.removeFirst();
                    }
                    // log each line at debug level so user can enable debug
                    plugin.getLogger().debug("[{}] {}", server.getServerInfo().getName(), line);
                }
            } catch (Exception e) {
                plugin.getLogger().debug("Error while streaming process output for {}: {}", server.getServerInfo().getName(), e.getMessage());
            }
        }, "autoserver-output-" + server.getServerInfo().getName());
        t.setDaemon(true);
        t.start();
    }

    // Sleep for 1 second to give time for command to execute
    // This is only to catch immediate errors
    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
    }

    if (commandResult.failedToStart()) {
        throw new RuntimeException(commandResult.getErrorMessage());
    }

    plugin.getLogger().debug("Command Result: {}", commandResult);
    if (commandResult.isTerminated()) {
        // Collect tail output for diagnostics
        StringBuilder out = new StringBuilder();
        synchronized (tail) {
            for (String l : tail) {
                out.append(l).append(System.lineSeparator());
            }
        }

        if (out.length() > 0) {
            plugin.getLogger().info("The command exited quickly, which may indicate an error. Here is the output: {}{}{}", AnsiColors.YELLOW, out.toString(), AnsiColors.RESET);
        }
        if (commandResult.getExitCode() != 0) {
            plugin.getLogger().error("Process exited with a non-zero exit code: {}", commandResult.getExitCode());
            throw new RuntimeException("Command failed to run.");
        }
    }
    return "Command ran successfully";
}

[TropicSnowJPR]

i just realized i made a mistake because the sever dont auto stop:

[14:32:53 INFO] [autoserver]: Running stop command for survival server. "screen -p 0 -S Survival -X stuff "stop
[14:32:53 ERROR] [autoserver]: Failed to stop server: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner
[14:32:53 ERROR] [autoserver]: error: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner

[Artimba]

i just realized i made a mistake because the sever dont auto stop:

[14:32:53 INFO] [autoserver]: Running stop command for survival server. "screen -p 0 -S Survival -X stuff "stop [14:32:53 ERROR] [autoserver]: Failed to stop server: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner [14:32:53 ERROR] [autoserver]: error: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner

Make sure you are building with a high enough version of gradle. I ran into the issue of CommandRunner not being found when Shadow wasn't being built because my gradle version was too old.

Also good work sharing this. I'd figure we should spike a PR with a fallback ping method. I didn't do it myself because my implementation of it was pretty scrapped together. Didn't integrate with config or proper logging, and I still have some pretty excessive log spam. I got it to the point it worked for me, but not to my standards of sharing lol. Not sure what the trade offs of using a raw TCP ping over the netty based one, but I'd figure having it be a config toggle would handle most concerns.

[TropicSnowJPR]

i just realized i made a mistake because the sever dont auto stop:
[14:32:53 INFO] [autoserver]: Running stop command for survival server. "screen -p 0 -S Survival -X stuff "stop [14:32:53 ERROR] [autoserver]: Failed to stop server: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner [14:32:53 ERROR] [autoserver]: error: java.lang.NoClassDefFoundError: me/artificial/autoserver/common/CommandRunner

Make sure you are building with a high enough version of gradle. I ran into the issue of CommandRunner not being found when Shadow wasn't being built because my gradle version was too old.

Also good work sharing this. I'd figure we should spike a PR with a fallback ping method. I didn't do it myself because my implementation of it was pretty scrapped together. Didn't integrate with config or proper logging, and I still have some pretty excessive log spam. I got it to the point it worked for me, but not to my standards of sharing lol. Not sure what the trade offs of using a raw TCP ping over the netty based one, but I'd figure having it be a config toggle would handle most concerns.

The thing with the gradle version is a great idea i will try it as soon as i have time thanks for the tip!

[TropicSnowJPR]

@Artimba if possible do you still have ur gradle config or rather the version u were using that would be great because i did not get it to work myself

[artificial-720]

Thank you for all the interaction. I have been busy, so I haven't been able to touch this. I have some free time tomorrow, so I'll get an updated version out.

[Artimba]

@Artimba if possible do you still have ur gradle config or rather the version u were using that would be great because i did not get it to work myself

So I actually just found out my local repository seems to have deleted itself from existence. I was running it from WSL but my WSL instance seems to have atomized itself and took its folders with it. Fun. I can tell you that I updated to gradle 8.11 and Shadow to 9.2.2. I wish I could send the configs themselves but alas.

[TropicSnowJPR]

@Artimba if possible do you still have ur gradle config or rather the version u were using that would be great because i did not get it to work myself

So I actually just found out my local repository seems to have deleted itself from existence. I was running it from WSL but my WSL instance seems to have atomized itself and took its folders with it. Fun. I can tell you that I updated to gradle 8.11 and Shadow to 9.2.2. I wish I could send the configs themselves but alas.

Thanks that worked 👍