make the minecraft script fully manage the minecraft servert process on-demand

scripts/minecraft.js

@@ -7,14 +7,21 @@
 
 import fetch from "node-fetch";
 import { WebSocket } from "ws";
+import { spawn } from "node:child_process";
 import Rcon from "rcon";
 
+
+
 const TOKEN = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6InN0YWdpbmctbWluZWNyYWZ0LWJyaWRnZSIsImF2YXRhclVSTCI6bnVsbCwiZGlzY29yZElEIjoiMCIsImd1aWxkQWNjZXNzIjpbIjczNjI5MjUwOTEzNDc0OTgwNyJdLCJpc1N1cGVyVG9rZW4iOnRydWUsImlhdCI6MTY0NDQ1MzM4MX0.-XIBl6VLnXVwve9iqhWs51ABZkm1i_v1tS6X01SPk3U"; // A supertoken is required to send messages from Minecraft.
 const TARGET_GUILD_ID = "_";
 const TARGET_CHANNEL_ID = "_";
 const ORIGIN = "http://localhost:4050";
 const GATEWAY_ORIGIN = "ws://localhost:4050/gateway";
-const FRONTEND_ORIGIN = "http://localhost:4050/";
+
+
+const chatMessageRegex = /^\[(?:.*?)\]: \<(?<username>[a-zA-Z0-9]+)\> (?<message>.*)/;
+const joinNotificationRegex = /^\[(?:.*?)\]: (?<username>[a-zA-Z0-9]+) joined the game/;
+const leaveNotificationRegex = /^\[(?:.*?)\]: (?<username>[a-zA-Z0-9]+) left the game/;
 const messageSchema = { t: "number", d: "object" };
 const messageTypes = {
     HELLO: 0,
@@ -22,17 +29,29 @@ const messageTypes = {
     READY: 2,
     EVENT: 3
 };
-const EXPRIMENTAL_ACCOUNT_LINK = false;
 
-const chatMessageRegex = /^\[(?:.*?)\]: \<(?<username>[a-zA-Z0-9]+)\> (?<message>.*)/;
-const joinNotificationRegex = /^\[(?:.*?)\]: (?<username>[a-zA-Z0-9]+) joined the game/;
-const leaveNotificationRegex = /^\[(?:.*?)\]: (?<username>[a-zA-Z0-9]+) left the game/;
-const rconConnection = new Rcon("localhost", "25575", process.env.RCON_PASSWORD);
+const createServerChildProcess = () => {
+    const serverJar = process.env.SERVER_JAR;
+    if (!serverJar) {
+        throw new Error("SERVER_JAR not found in env");
+    }
 
-const pendingHandoffs = new Map();
-const usernameToToken = new Map();
+    const serverPwd = process.env.SERVER_PWD;
+    if (!serverPwd) {
+        throw new Error("SERVER_PWD not found in env");
+    }
 
-export default class GatewayClient {
+    return spawn("java", [
+        "-Xms1G", "-Xmx5G", "-XX:+UseG1GC", "-XX:+ParallelRefProcEnabled", "-XX:MaxGCPauseMillis=200", "-XX:+UnlockExperimentalVMOptions", "-XX:+DisableExplicitGC", "-XX:+AlwaysPreTouch", "-XX:G1NewSizePercent=30",
+        "-XX:G1MaxNewSizePercent=40", "-XX:G1HeapRegionSize=8M", "-XX:G1ReservePercent=20", "-XX:G1HeapWastePercent=5", "-XX:G1MixedGCCountTarget=4", "-XX:InitiatingHeapOccupancyPercent=15", "-XX:G1MixedGCLiveThresholdPercent=90",
+        "-XX:G1RSetUpdatingPauseTimePercent=5", "-XX:SurvivorRatio=32", "-XX:+PerfDisableSharedMem", "-XX:MaxTenuringThreshold=1", "-Dusing.aikars.flags=https://mcflags.emc.gs",
+        "-Daikars.new.flags=true", "-jar", serverJar, "nogui"
+    ], {
+        cwd: serverPwd
+    });
+};
+
+class GatewayClient {
     constructor(gatewayPath) {
         this.gatewayPath = gatewayPath;
         this.ws = null;
@@ -137,156 +156,234 @@ export default class GatewayClient {
     }
 }
 
+class Bridge {
+    constructor() {
+        this.gatewayConnection = new GatewayClient(GATEWAY_ORIGIN);
+        this.process = null;
+        this.rconConnection = null;
+        this.playerCount = 0;
+        this.serverStartedAt = null;
 
-async function sendBridgeMessageAs(guildId, channelId, content, username=undefined, avatarURL=undefined) {
-    return await fetch(`${ORIGIN}/api/v1/guilds/${guildId}/channels/${channelId}/messages/create`, {
-        method: "POST",
-        body: JSON.stringify({
-            content,
-            username,
-            avatarURL
-        }),
-        headers: {
-            "content-type": "application/json",
-            "authorization": TOKEN
+        this.gatewayConnection.onEvent = (e) => {
+            if (
+                e.eventType === "MESSAGE_CREATE" &&
+                e.message.channel_id === TARGET_CHANNEL_ID &&
+                e.message.guild_id === TARGET_GUILD_ID &&
+                !e.message.webhook_id
+            ) {
+                if (e.message.content === "!:mc-start") {
+                    this.userRequestedServerJob();
+                    return;
+                } else if (e.message.content === "!:mc-status") {
+                    this.sendBridgeMessageAs(TARGET_GUILD_ID,
+                        TARGET_CHANNEL_ID,
+                        `:scroll: **Server information**\n**Player Count**: ${this.playerCount}\n**Started**: <t:${this.serverStartedAt}:R>`,
+                        null,
+                        null
+                    );
+                    return;
+                }
+
+                this.sendMinecraftMessageAs(
+                    e.message.author.username,
+                    e.message.content,
+                    e.message.attachments,
+                    e.message.referenced_message
+                );
+            }
+        };
+    }
+
+    rconConnect() {
+        if (this.rconConnection) {
+            this.rconConnection.disconnect();
+            this.rconConnection = null;
         }
-    });
-}
 
-async function sendMinecraftMessageAs(rcon, username, content, attachments, referencedMessage=null) {
-    if (!attachments) {
-        attachments = [];
-    }    
-
-    const tellrawPayload = [
-        { text: "[" },
-        { text: `${username}`, color: "gray" },
-        { text: "]" },
-        { text: " " },
-    ];
-
-    if (referencedMessage) {
-        let trimmedContent = referencedMessage.content.substring(0, 50);
-        if (trimmedContent !== referencedMessage.content) {
-            trimmedContent += "...";
-        }
-        tellrawPayload.push({
-            text: `<replying to ${referencedMessage.author.username}: ${trimmedContent}>`
+        this.rconConnection = new Rcon("localhost", "25575", process.env.RCON_PASSWORD);
+        this.rconConnection.connect();
+        this.rconConnection.on("error", (e) => {
+            if (e.code === "ECONNREFUSED" && e.syscall === "connect") {
+                console.warn("rcon: ECONNREFUSED, reconnecting in 5s...");
+                setTimeout(() => {
+                    console.log("rcon: reconnecting...");
+                    this.rconConnect();
+                }, 5000);
+            } else {
+                console.error("rcon: got error", e);
+                console.error("rcon: don't know what to do, disconnecting rcon due to previous error");
+                this.rconConnection.disconnect();
+                this.rconConnection = null;
+            }
         });
-        tellrawPayload.push({
-            text: " "
+        this.rconConnection.on("connect", () => {
+            this.serverStartedAt = Date.now();
+            this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":zap: Server started!", null, null);
         });
     }
 
-    attachments.forEach((e) => {
-        tellrawPayload.push({
-            text: `<open attachment: ${e.filename || "[unknown]"}>`,
-            color: "gray",
-            clickEvent: {
-                action: "open_url",
-                value: e.proxy_url
-            }
-        });
-        tellrawPayload.push({
-            text: " "
-        });
-    });
+    start() {
+        this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":bridge_at_night: The bridge server has started! Type `!:mc-start` in the chat to start the Minecraft server. Any further updates related to the server's status will be sent in this channel.", null, null);
+        this.gatewayConnection.connect(TOKEN);
+    }
 
-    tellrawPayload.push({ text: content });
+    spawnProcess() {
+        if (this.process) {
+            console.warn("server job: spawnProcess(): another instance already exists");
+            this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":thinking: It seems like the server is already running! If you think this is a mistake, contact the server manager.", null, null);
+            return;
+        }
+
+        console.log("server job: spawning");
+        this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":clock5: Starting server...", null, null);
+
+        this.process = createServerChildProcess();
+
+        this.process.stderr.on("data", async (rawDataBuffer) => {
+            const stringData = rawDataBuffer.toString().trim();
+            console.error(`[server process stderr]: ${stringData}`);
+        });
+
+        this.process.stdout.on("data", async (rawDataBuffer) => {
+            const stringData = rawDataBuffer.toString().trim();
+            console.log(`[server process stdout]: ${stringData}`);
     
-    rcon.send(`tellraw @a ${JSON.stringify(tellrawPayload)}`);
-}
-
-async function startHandoffForUser(username) {
-    const handoffRes = await fetch(`${ORIGIN}/api/v1/tokens/handoff/create`, {
-        method: "POST",
-        body: JSON.stringify({}),
-        headers: {
-            "content-type": "application/json",
-            "authorization": TOKEN
-        }
-    });
-    const { token: handoffToken, dispatchUUID } = (await handoffRes.json());
-
-    pendingHandoffs.set(dispatchUUID, username);
-    // TODO: probably not a good idea
-    setTimeout(() => {
-        pendingHandoffs.delete(dispatchUUID);
-    }, 40000);
-
-    return handoffToken;
-}
-
-async function main() {
-    rconConnection.on("error", (e) => {
-        console.error("rcon: got error", e);
-        if (!rconConnection.hasAuthed) {
-            console.log("rcon: reconnecting in 5000ms due to error before hasAuthed (server might not be up yet?)");
-            setTimeout(() => {
-                rconConnection.connect();
-            }, 5000);
-        }
-    });
-
-    const gateway = new GatewayClient(GATEWAY_ORIGIN);
-    gateway.onEvent = (e) => {
-        if (e.eventType === "$BRIDGE_HANDOFF_FULFILLMENT") {
-            const username = pendingHandoffs.get(e.dispatchUUID);
-            if (!username)
+            const joinResult = joinNotificationRegex.exec(stringData);
+            if (joinResult) {
+                this.onPlayerCountUpdate(1);
+                await this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, `:door: **${joinResult.groups.username}** joined the game. Player count is ${this.playerCount}.`, null, null);
                 return;
+            }
+    
+            const leaveResult = leaveNotificationRegex.exec(stringData);
+            if (leaveResult) {
+                this.onPlayerCountUpdate(-1);
+                await this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, `:door: **${leaveResult.groups.username}** left the game. Player count is ${this.playerCount}.`, null, null);
+                return;
+            }
+    
+            const messageResult = chatMessageRegex.exec(stringData);
+            if (messageResult) {
+                await this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, messageResult.groups.message, messageResult.groups.username, null);
+            }
+        });
 
-            usernameToToken.set(username, e.token);
+        this.process.on("spawn", () => {
+            console.log("server process: spawn");
+            this.process.stdout.resume();
+            this.process.stderr.resume();
+            this.rconConnect();
+        });
+    
+        this.process.on("exit", (code) => {
+            console.log(`server process: exited with code ${code}`);
+            this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":zap: Server is now closed.", null, null);
+            this.process = null;
+        });
 
-            sendMinecraftMessageAs(rconConnection, "Minecraft Bridge System", `${username} has been successfully linked to a bridge token.`, null, null);
-        } else if (e.eventType === "MESSAGE_CREATE" && e.message.channel_id === TARGET_CHANNEL_ID && e.message.guild_id === TARGET_GUILD_ID && !e.message.webhook_id) {
-            sendMinecraftMessageAs(rconConnection, e.message.author.username, e.message.content, e.message.attachments, e.message.referenced_message);
+        this.process.on("error", (e) => {
+            console.error("server process: error", e);
+            this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":flushed: Server process error.", null, null);
+            this.process = null;
+        });
+    }
+
+    async sendBridgeMessageAs(guildId, channelId, content, username=undefined, avatarURL=undefined) {
+        return await fetch(`${ORIGIN}/api/v1/guilds/${guildId}/channels/${channelId}/messages/create`, {
+            method: "POST",
+            body: JSON.stringify({
+                content,
+                username,
+                avatarURL
+            }),
+            headers: {
+                "content-type": "application/json",
+                "authorization": TOKEN
+            }
+        });
+    }
+
+    sendMinecraftMessageAs(username, content, attachments=[], referencedMessage=null) {  
+        const tellrawPayload = [
+            { text: "[" },
+            { text: `${username}`, color: "gray" },
+            { text: "]" },
+            { text: " " },
+        ];
+    
+        if (referencedMessage) {
+            let trimmedContent = referencedMessage.content.substring(0, 70);
+            if (trimmedContent !== referencedMessage.content) {
+                trimmedContent += "...";
+            }
+            tellrawPayload.push({
+                text: `<replying to ${referencedMessage.author.username}: ${trimmedContent}>`,
+                color: "gray"
+            });
+            tellrawPayload.push({
+                text: " "
+            });
         }
-    };
-    rconConnection.connect();
-    gateway.connect(TOKEN);
-
-    process.stdin.resume();
-    process.stdin.on("data", async (rawDataBuffer) => {
-        const stringData = rawDataBuffer.toString().trim();
-        console.log(stringData);
-
-        const joinResult = joinNotificationRegex.exec(stringData);
-        if (joinResult) {
-            await sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, `**${joinResult.groups.username}** joined the game`, null, null);
-            return;
-        }
-
-        const leaveResult = leaveNotificationRegex.exec(stringData);
-        if (leaveResult) {
-            await sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, `**${leaveResult.groups.username}** left the game`, null, null);
-            return;
-        }
-
-        const messageResult = chatMessageRegex.exec(stringData);
-        if (messageResult) {
-            if (EXPRIMENTAL_ACCOUNT_LINK && messageResult.groups.message === "!:minecraft-link") {
-                try {
-                    const handoffToken = await startHandoffForUser(messageResult.groups.username);
-                    const handoffLink = `${FRONTEND_ORIGIN}#token_handoff,,${handoffToken}`;
-                    sendMinecraftMessageAs(
-                        rconConnection,
-                        "Minecraft Bridge System",
-                        `${messageResult.groups.username}: Click on the attached link to finish linking your account. You have 40 seconds.`,
-                        [
-                            {
-                                filename: `link account to ${messageResult.groups.username}`,
-                                proxy_url: handoffLink
-                            }
-                        ]
-                    );
-                } catch(e) {
-                    sendMinecraftMessageAs(rconConnection, "Minecraft Bridge System", `Failed to create link for ${messageResult.groups.username}.`, null, null);
+    
+        attachments.forEach((e) => {
+            tellrawPayload.push({
+                text: `<open attachment: ${e.filename || "[unknown]"}>`,
+                color: "gray",
+                clickEvent: {
+                    action: "open_url",
+                    value: e.proxy_url
                 }
+            });
+            tellrawPayload.push({
+                text: " "
+            });
+        });
+    
+        tellrawPayload.push({ text: content });
+        
+        if (this.rconConnection)
+            this.rconConnection.send(`tellraw @a ${JSON.stringify(tellrawPayload)}`);
+    }
+
+    onPlayerCountUpdate(amount) {
+        this.playerCount += amount;
+
+        if (this.playerCount === 0) {
+            this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":wave: Everyone has left the server. Closing...", null, null);
+            console.log("server job: playerCount has reached 0, will close child server process");
+            if (this.process) {
+                console.log("server job: closing process...");
+                this.process.kill("SIGINT");
             } else {
-                await sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, messageResult.groups.message, messageResult.groups.username, null);
+                console.warn("server job: no process to kill");
             }
         }
+    }
+
+    userRequestedServerJob() {
+        console.log("server job: user requested server job, spawning...");
+        this.spawnProcess();
+
+        // wait for 5 minutes - if no one has joined the server in that time, close it
+        setTimeout(() => {
+            if (this.playerCount === 0) {
+                console.log("server job: no players on server after 5 minutes, closing...");
+                this.sendBridgeMessageAs(TARGET_GUILD_ID, TARGET_CHANNEL_ID, ":pensive: Server was started, yet no one joined after 5 minutes. Closing again...", null, null);
+            }
+        }, 300000);
+    }
+}
+
+function main() {
+    const bridge = new Bridge();
+    bridge.start();
+
+    process.on("beforeExit", () => {
+        if (bridge.process) {
+            console.log("server process: killing on parent exit");
+            bridge.process.kill("SIGINT");
+        }
     });
 }
 
-await main();
+main();