vjudge: prevent race cond

packages/vjudge/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@hydrooj/vjudge",
-    "version": "1.0.4",
+    "version": "1.0.5",
     "description": "Submit problems to remote oj",
     "main": "package.json",
     "repository": "https://github.com/hydro-dev/Hydro.git",

packages/vjudge/src/model.ts

@@ -13,6 +13,7 @@ import { BasicProvider, IBasicProvider, RemoteAccount } from './interface';
 const coll = db.collection('vjudge');
 const Pool = {};
 const logger = new Logger('vjudge');
+const syncing = {};
 
 class Service {
     api: IBasicProvider;
@@ -37,7 +38,9 @@ class Service {
         while (pids.length) {
             logger.info(`${domainId}: Syncing page ${page}`);
             for (const pid of pids) {
-                if (await ProblemModel.get(domainId, pid)) continue;
+                if (syncing[`${domainId}/${pid}`] || await ProblemModel.get(domainId, pid)) continue;
+                syncing[`${domainId}/${pid}`] = true;
+                try {
                     const res = await this.api.getProblem(pid);
                     if (!res) continue;
                     const id = await ProblemModel.add(domainId, pid, res.title, res.content, 1, res.tag, false);
@@ -48,6 +51,9 @@ class Service {
                         await ProblemModel.addTestdata(domainId, id, key, res.data[key]);
                     }
                     logger.info(`${domainId}: problem ${id} sync done`);
+                } finally {
+                    delete syncing[`${domainId}/${pid}`];
+                }
                 await sleep(5000);
             }
             page++;