Use Socket.IO to communicate with web server

daemon-config-example.json

@@ -1,4 +1,6 @@
 {
+    "ServerUrl": "http://127.0.0.1:5283/",
+    "ServerToken": "",
     "RabbitMQUrl": "amqp://localhost/",
     "RedisUrl": "redis://127.0.0.1:6379",
     "TestData": "/opt/syzoj/data/testdata",

package.json

@@ -32,6 +32,7 @@
     "request-promise": "^4.2.1",
     "simple-sandbox": "^0.3.5",
     "socket.io": "^2.0.3",
+    "socket.io-client": "^2.2.0",
     "source-map-support": "^0.4.16",
     "syspipe": "^0.1.5",
     "tar": "^3.2.1",
@@ -56,6 +57,7 @@
     "@types/request": "^2.0.3",
     "@types/request-promise": "^4.1.37",
     "@types/socket.io": "^1.4.30",
+    "@types/socket.io-client": "^1.4.32",
     "@types/uuid": "^3.4.1",
     "@types/winston": "^2.3.5",
     "typescript": "^2.5.1"

src/daemon/cleanup.ts

@@ -1,8 +1,10 @@
-import {disconnect as disconnectRMQ } from './rmq';
+import { disconnect as disconnectRMQ } from './rmq';
+import { disconnect as disconnectSIO } from './remote';
 import winston = require('winston');
 
 export function cleanUp(retCode: number) {
     winston.info('Cleaning up...');
     disconnectRMQ();
-    process.exit(1);
+    disconnectSIO();
+    process.exit(retCode);
 }

src/daemon/config.ts

@@ -4,6 +4,8 @@ import winston = require('winston');
 import { configureWinston } from '../winston-common';
 
 export interface ConfigStructure {
+    serverUrl: string;
+    serverToken: string;
     rabbitMQ: string;
     testDataDirectory: string;
     priority: number;
@@ -25,6 +27,8 @@ function readJSON(path: string): any {
 
 const configJSON = readJSON(options["config"]);
 export const globalConfig: ConfigStructure = {
+    serverUrl: configJSON.ServerUrl,
+    serverToken: configJSON.ServerToken,
     rabbitMQ: configJSON.RabbitMQUrl,
     testDataDirectory: configJSON.TestData,
     priority: configJSON.Priority,

src/daemon/index.ts

@@ -4,30 +4,32 @@ import winston = require('winston');
 import { globalConfig as Cfg } from './config';
 import util = require('util');
 import rmq = require('./rmq');
+import remote = require('./remote');
 import { judge } from './judge';
 import { JudgeResult, ErrorType, ProgressReportType, OverallResult } from '../interfaces';
 
 (async function () {
     winston.info("Daemon starts.");
+    await remote.connect();
     await rmq.connect();
     winston.info("Start consuming the queue.");
-    await rmq.waitForTask(async (task) => {
+    await remote.waitForTask(async (task) => {
         let result: OverallResult;
         try {
-            await rmq.reportProgress({ taskId: task.content.taskId, type: ProgressReportType.Started, progress: null });
+            await remote.reportProgress({ taskId: task.content.taskId, type: ProgressReportType.Started, progress: null });
             result = await judge(task.content, task.extraData, async (progress) => {
-                await rmq.reportProgress({ taskId: task.content.taskId, type: ProgressReportType.Progress, progress: progress });
+                await remote.reportProgress({ taskId: task.content.taskId, type: ProgressReportType.Progress, progress: progress });
             }, async (progress) => {
                 const data = { taskId: task.content.taskId, type: ProgressReportType.Compiled, progress: progress };
-                await rmq.reportProgress(data);
+                await remote.reportProgress(data);
-                await rmq.reportResult(data);
+                await remote.reportResult(data);
             });
         } catch (err) {
             winston.warn(`Judge error!!! TaskId: ${task.content.taskId}`, err);
             result = { error: ErrorType.SystemError, systemMessage: `An error occurred.\n${err.toString()}` };
         }
         const resultReport = { taskId: task.content.taskId, type: ProgressReportType.Finished, progress: result };
-        await rmq.reportProgress(resultReport);
+        await remote.reportProgress(resultReport);
-        await rmq.reportResult(resultReport);
+        await remote.reportResult(resultReport);
     });
 })().then(() => { winston.info("Initialization logic completed."); }, (err) => { winston.error(util.inspect(err)); process.exit(1); });

src/daemon/remote.ts

@@ -0,0 +1,75 @@
+import * as url from 'url';
+import * as util from 'util';
+import { globalConfig as Cfg } from './config';
+import msgpack = require('msgpack-lite');
+import winston = require('winston');
+import { ProgressReportData } from '../interfaces';
+import { JudgeTask } from './interfaces';
+import * as SocketIOClient from 'socket.io-client';
+
+let socketIOConnection: SocketIOClient.Socket;
+let cancelCurrentPull: Function;
+
+export async function connect() {
+    const socketIOUrl = url.resolve(Cfg.serverUrl, 'judge');
+    winston.verbose(`Connect to Socket.IO "${socketIOUrl}"...`);
+    socketIOConnection = SocketIOClient(socketIOUrl);
+
+    socketIOConnection.on('disconnect', () => {
+        winston.verbose(`Disconnected from Socket.IO "${socketIOUrl}"...`);
+        if (cancelCurrentPull) cancelCurrentPull();
+    });
+}
+
+export async function disconnect() {
+    socketIOConnection.close();
+}
+
+export async function waitForTask(handle: (task: JudgeTask) => Promise<void>) {
+    while (true) {
+        winston.verbose('Waiting for new task...');
+        await new Promise((resolve, reject) => {
+            // This should be cancelled if socket disconnects.
+            let cancelled = false;
+            cancelCurrentPull = () => {
+                cancelled = true;
+                winston.verbose('Cancelled task polling since disconnected.');
+                resolve();
+            }
+
+            socketIOConnection.once('onTask', async (payload: Buffer, ack: Function) => {
+                // After cancelled, a new pull is emitted while socket's still disconnected.
+                if (cancelled) return;
+
+                try {
+                    winston.verbose('onTask.');
+                    await handle(msgpack.decode(payload));
+                    ack();
+                    resolve();
+                } catch (e) {
+                    reject(e);
+                }
+            });
+
+            socketIOConnection.emit('waitForTask', Cfg.serverToken, () => {
+                winston.verbose('waitForTask acked.');
+            });
+        });
+    }
+}
+
+// Difference between result and progress:
+// The `progress' is to be handled by *all* frontend proxies and pushed to all clients.
+// The `result' is to be handled only *once*, and is to be written to the database.
+
+export async function reportProgress(data: ProgressReportData) {
+    winston.verbose('Reporting progress', data);
+    const payload = msgpack.encode(data);
+    socketIOConnection.emit('reportProgress', Cfg.serverToken, payload);
+}
+
+export async function reportResult(data: ProgressReportData) {
+    winston.verbose('Reporting result', data);
+    const payload = msgpack.encode(data);
+    socketIOConnection.emit('reportResult', Cfg.serverToken, payload);
+}

src/daemon/rmq.ts

@@ -4,23 +4,15 @@ import msgpack = require('msgpack-lite');
 import winston = require('winston');
 import util = require('util');
 import uuid = require('uuid');
-import { RPCRequest, RPCReplyType, JudgeResult, ProgressReportData, RPCReply } from '../interfaces';
+import { RPCRequest, RPCReplyType, RPCReply } from '../interfaces';
 import { cleanUp } from './cleanup';
-import { JudgeTask } from './interfaces';
 import * as rmqCommon from '../rmq-common';
 
 let amqpConnection: amqp.Connection;
-let publicChannel: amqp.Channel;
 
 export async function connect() {
     winston.verbose(`Connecting to RabbitMQ "${Cfg.rabbitMQ}"...`);
     amqpConnection = await amqp.connect(Cfg.rabbitMQ);
-    winston.debug(`Connected to RabbitMQ, asserting queues`);
-    publicChannel = await newChannel();
-    await rmqCommon.assertTaskQueue(publicChannel);
-    await rmqCommon.assertProgressReportExchange(publicChannel);
-    await rmqCommon.assertJudgeQueue(publicChannel);
-    await rmqCommon.assertResultReportQueue(publicChannel);
     amqpConnection.on('error', (err) => {
         winston.error(`RabbitMQ connection failure: ${err.toString()}`);
         cleanUp(2);
@@ -35,22 +27,6 @@ async function newChannel(): Promise<amqp.Channel> {
     return await amqpConnection.createChannel();
 }
 
-export async function waitForTask(handle: (task: JudgeTask) => Promise<void>) {
-    await rmqCommon.waitForTask(amqpConnection, rmqCommon.judgeQueueName, Cfg.priority, () => false, handle);
-}
-
-export async function reportProgress(data: ProgressReportData) {
-    winston.verbose('Reporting progress', data);
-    const payload = msgpack.encode(data);
-    publicChannel.publish(rmqCommon.progressExchangeName, '', payload);
-}
-
-export async function reportResult(data: ProgressReportData) {
-    winston.verbose('Reporting result', data);
-    const payload = msgpack.encode(data);
-    publicChannel.sendToQueue(rmqCommon.resultReportQueueName, payload);
-}
-
 // started: Callback when this task is started.
 export async function runTask(task: RPCRequest, priority: number, started?: () => void): Promise<any> {
     const correlationId = uuid();

src/rmq-common.ts

@@ -1,12 +1,9 @@
 import amqp = require('amqplib');
-import msgpack = require('msgpack-lite');
 import winston = require('winston');
+import msgpack = require('msgpack-lite');
 
 export const maxPriority = 5;
 export const taskQueueName = 'task';
-export const progressExchangeName = 'progress';
-export const resultReportQueueName = 'result';
-export const judgeQueueName = 'judge';
 
 export async function assertTaskQueue(channel: amqp.Channel) {
     await channel.assertQueue(taskQueueName, {
@@ -14,26 +11,6 @@ export async function assertTaskQueue(channel: amqp.Channel) {
     });
 }
 
-// Difference between result and progress:
-// The `progress' is to be handled by *all* frontend proxies and pushed to all clients.
-// The `result' is to be handled only *once*, and is to be written to the database.
-
-export async function assertProgressReportExchange(channel: amqp.Channel) {
-    await channel.assertExchange(progressExchangeName, 'fanout', { durable: false });
-}
-
-export async function assertResultReportQueue(channel: amqp.Channel) {
-    await channel.assertQueue(resultReportQueueName, { durable: true });
-}
-
-export async function assertJudgeQueue(channel: amqp.Channel) {
-    await channel.assertQueue(judgeQueueName, {
-        maxPriority: maxPriority,
-        durable: true
-    });
-}
-
-
 export async function waitForTask<T>(conn: amqp.Connection, queueName: string, priority: number, retry: (err: Error) => boolean, handle: (task: T) => Promise<void>) {
     const channel = await conn.createChannel();
     channel.prefetch(1);