diff --git a/app.js b/app.js
index 45682c2..971bedb 100644
--- a/app.js
+++ b/app.js
@@ -11,6 +11,7 @@ const app = express();
 const handlers = {};
 const middlewares = {};
 const dbPools = {};
+const lockHash = {};
 let sessionClass = null;
 let useMiddlewares = [];
 
@@ -204,6 +205,24 @@ registerHandler('Ops', 'selfChecking', async (req, rsp) => {
   }
 });
 
+async function lock(key) {
+  if (key in lockHash) {
+    lockHash[key] += 1;
+  } else {
+    lockHash[key] = 1;
+  }
+  const oldTimes = lockHash[key];
+  while (lockHash[key] == oldTimes) {
+    await sleep(0.05);
+  }
+}
+
+function unLock(key) {
+  if (key in lockHash) {
+    lockHash[key] -= 1;
+  }
+}
+
 exports.init = init;
 exports.listen = listen;
 exports.get = get;
@@ -219,3 +238,5 @@ exports.getPid = getPid;
 exports.getNodeId = getNodeId;
 exports.getInstanceId = getInstanceId;
 exports.sleep = sleep;
+exports.lock = lock;
+exports.unLock = unLock;