MongoError:在使用 NextJs api 时拓扑被破坏 [英] MongoError: topology was destroyed while using with NextJs api
问题描述
我正在使用 Vercel 无服务器功能为 Next.js 应用程序制作 API 端点.我正在使用 MongoDB 来存储对象数组.
I am Using Vercel Serverless funtions to make API Endpoints for Next.js application. I am Using MongoDB to store an Array of Objects.
我有这个无服务器功能
// api/global/addlink.js
const MongoClient = require("mongodb").MongoClient;
const { ObjectId } = require("mongodb");
const client = new MongoClient(process.env.DB_URI, {});
export default async (req, res) => {
await client.connect();
const link = JSON.parse(req.body)["link"];
const query = { _id: ObjectId(JSON.parse(req.body)["_id"]) };
const result = await client
.db("myio_guests")
.collection("link_groups")
.findOneAndUpdate(query, {
$push: {
links: link,
},
});
res.json({
message: "link added successfully",
result: result,
});
await client.close();
};
此函数每运行 2 次就会报错.
This function Gives error every 2nd time it runs.
我尝试了 4 次调用，该函数使用来自前端的 fetch post 请求，但只保存了 2 个条目，分别是第 1 个和第 3 个条目.在第 2 次和第 4 次调用的情况下，发生此错误:
I tried 4 invocations, of the function using fetch post request from my frontend, but only 2 entries are saved those are 1st and 3rd entry. In case of 2nd and 4th invocation this error occured:
2021-01-26T14:14:18.964Z cae61486-ecb3-4726-aa8c-f8e95d9326ad WARN the options [servers] is not supported
2021-01-26T14:14:18.964Z cae61486-ecb3-4726-aa8c-f8e95d9326ad WARN the options [caseTranslate] is not supported
2021-01-26T14:14:18.964Z cae61486-ecb3-4726-aa8c-f8e95d9326ad WARN the options [dbName] is not supported
2021-01-26T14:14:18.964Z cae61486-ecb3-4726-aa8c-f8e95d9326ad WARN the options [srvHost] is not supported
2021-01-26T14:14:18.964Z cae61486-ecb3-4726-aa8c-f8e95d9326ad WARN the options [credentials] is not supported
2021-01-26T14:14:20.203Z cae61486-ecb3-4726-aa8c-f8e95d9326ad ERROR MongoError: topology was destroyed
at executeCommand (/var/task/node_modules/mongodb/lib/operations/db_ops.js:222:21)
at FindOneAndUpdateOperation.execute (/var/task/node_modules/mongodb/lib/operations/find_and_modify.js:107:5)
at executeOperation (/var/task/node_modules/mongodb/lib/operations/execute_operation.js:77:17)
at Collection.findOneAndUpdate (/var/task/node_modules/mongodb/lib/collection.js:1737:10)
at module.exports.lt9b.__webpack_exports__.default (/var/task/.next/serverless/pages/api/global/addlink.js:296:75)
at processTicksAndRejections (internal/process/task_queues.js:97:5)
at async apiResolver (/var/task/node_modules/next/dist/next-server/server/api-utils.js:8:1)
at async /var/task/.next/serverless/pages/api/global/addlink.js:137:387
2021-01-26T14:14:20.203Z cae61486-ecb3-4726-aa8c-f8e95d9326ad ERROR MongoError: topology was destroyed
at executeCommand (/var/task/node_modules/mongodb/lib/operations/db_ops.js:222:21)
at FindOneAndUpdateOperation.execute (/var/task/node_modules/mongodb/lib/operations/find_and_modify.js:107:5)
at executeOperation (/var/task/node_modules/mongodb/lib/operations/execute_operation.js:77:17)
at Collection.findOneAndUpdate (/var/task/node_modules/mongodb/lib/collection.js:1737:10)
at module.exports.lt9b.__webpack_exports__.default (/var/task/.next/serverless/pages/api/global/addlink.js:296:75)
at processTicksAndRejections (internal/process/task_queues.js:97:5)
at async apiResolver (/var/task/node_modules/next/dist/next-server/server/api-utils.js:8:1)
at async /var/task/.next/serverless/pages/api/global/addlink.js:137:387
2021-01-26T14:14:20.204Z cae61486-ecb3-4726-aa8c-f8e95d9326ad ERROR Unhandled Promise Rejection {"errorType":"Runtime.UnhandledPromiseRejection","errorMessage":"MongoError: topology was destroyed","reason":{"errorType":"MongoError","errorMessage":"topology was destroyed","name":"MongoError","stack":["MongoError: topology was destroyed"," at executeCommand (/var/task/node_modules/mongodb/lib/operations/db_ops.js:222:21)"," at FindOneAndUpdateOperation.execute (/var/task/node_modules/mongodb/lib/operations/find_and_modify.js:107:5)"," at executeOperation (/var/task/node_modules/mongodb/lib/operations/execute_operation.js:77:17)"," at Collection.findOneAndUpdate (/var/task/node_modules/mongodb/lib/collection.js:1737:10)"," at module.exports.lt9b.__webpack_exports__.default (/var/task/.next/serverless/pages/api/global/addlink.js:296:75)"," at processTicksAndRejections (internal/process/task_queues.js:97:5)"," at async apiResolver (/var/task/node_modules/next/dist/next-server/server/api-utils.js:8:1)"," at async /var/task/.next/serverless/pages/api/global/addlink.js:137:387"]},"promise":{},"stack":["Runtime.UnhandledPromiseRejection: MongoError: topology was destroyed"," at process.<anonymous> (/var/runtime/index.js:35:15)"," at process.emit (events.js:326:22)"," at processPromiseRejections (internal/process/promises.js:209:33)"," at processTicksAndRejections (internal/process/task_queues.js:98:32)"]}
Unknown application error occurred
如何在这样的无服务器案例中解决此问题?
How Can I solve this Issue on serverless case like this?
推荐答案
您遇到的问题来自这一行:
There issue you're having comes from this line:
await client.close();
来自文档:
MongoClient.close() - 关闭底层连接器，进而关闭所有打开的连接.一旦调用，此 Mongo 实例将无法再使用.
MongoClient.close() - closes the underlying connector, which in turn closes all open connections. Once called, this Mongo instance can no longer be used.
意味着当您关闭客户端时，任何其他打开的连接也会关闭.在您的情况下，#2 和 #4 在 #1 和 #3 之后不久开始运行(但在它们完成之前)，并且在它们仍在运行时关闭它们的连接.
Meaning when you close the client, any other open connections close aswell.
In your case #2 and #4 start running shortly after #1 and #3 (but before they are done), and you close the connection on them while they are still running.
同样来自文档:
MongoClient 类被设计为线程安全并在线程之间共享.通常，您仅为给定的数据库集群创建 1 个实例并在整个应用程序中使用它.
The MongoClient class is designed to be thread safe and shared among threads. Typically you create only 1 instance for a given database cluster and use it across your application.
最好的做法是为您的无状态函数进行一些状态管理(我知道)，拥有一个只为您的无状态函数提供连接的连接服务，这样管理错误也会更容易.
It would be a best practice to have some state management for your stateless functions (I know), have a connection service that just gives your stateless functions the connection, it would also be easier to manage errors this way.
解决您的问题的一个快速(且非常次优)的解决方案是在函数内定义连接，如下所示:
A quick (and very suboptimal) solution to your problem would be to define the connection within the function like so:
// remove the definition from here
export default async (req, res) => {
// and move it here
const client = new MongoClient(process.env.DB_URI, {});
await client.connect();
.....
await client.close();
};
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