Memory leak in Auth instantiation - frameworkChangeObservers never cleared

[mathbruyen]

Before opening, please confirm:

• I have searched for duplicate or closed issues and discussions.
• I have read the guide for submitting bug reports.
• I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.

JavaScript Framework

Not applicable

Amplify APIs

Authentication

Amplify Categories

auth

Environment information

  System:
    OS: Linux 5.10 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
    CPU: (8) x64 Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz
    Memory: 3.04 GB / 15.36 GB
    Container: Yes
    Shell: 5.1.4 - /bin/bash
  Binaries:
    Node: 20.5.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.8.0 - /usr/local/bin/npm
  Browsers:
    Chrome: 115.0.5790.170
  npmPackages:
    @types/express: ^4.17.14 => 4.17.17 
    @types/mocha: ^10.0.0 => 10.0.1 
    @types/node: ^18.11.17 => 18.17.3 
    @typescript-eslint/eslint-plugin: ^6.0.0 => 6.3.0 
    @typescript-eslint/parser: ^6.0.0 => 6.3.0 
    aws-amplify: ^5.1.4 => 5.3.6 
    compression: ^1.7.4 => 1.7.4 
    cookie-parser: ^1.4.6 => 1.4.6 
    css-loader: ^6.7.3 => 6.8.1 
    csurf: ^1.11.0 => 1.11.0 
    eslint: ^8.33.0 => 8.46.0 
    eslint-config-google: ^0.14.0 => 0.14.0 
    eslint-plugin-react: ^7.32.2 => 7.33.1 
    express: ^4.18.2 => 4.18.2 
    express-graphql: ^0.12.0 => 0.12.0 
    glob: ^10.0.0 => 10.3.3 (7.2.3, 7.2.0)
    graphql: ^16.6.0 => 16.7.1 (15.8.0)
    intl-messageformat: ^10.3.0 => 10.5.0 
    js-cookie: ^3.0.1 => 3.0.5 (2.2.1)
    jszip: ^3.10.1 => 3.10.1 
    mini-css-extract-plugin: ^2.7.2 => 2.7.6 
    mocha: ^10.2.0 => 10.2.0 
    nodemon: ^3.0.0 => 3.0.1 
    puppeteer: ^21.0.0 => 21.0.1 
    react: ^18.2.0 => 18.2.0 
    react-dom: ^18.2.0 => 18.2.0 
    react-redux: ^8.0.5 => 8.1.2 
    react-router-dom: ^6.8.1 => 6.14.2 
    redux: ^4.2.1 => 4.2.1 
    sass: ^1.58.0 => 1.64.2 
    sass-loader: ^13.2.0 => 13.3.2 
    ts-loader: ^9.4.1 => 9.4.4 
    typescript: ^5.0.0 => 5.1.6 
    webpack: ^5.75.0 => 5.88.2 
    webpack-assets-manifest: ^5.1.0 => 5.1.0 
    webpack-cli: ^5.0.1 => 5.1.4 
    webpack-node-externals: ^3.0.0 => 3.0.0 
    zip-stream: ^4.1.0 => 4.1.0 
  npmGlobalPackages:
    corepack: 0.19.0
    npm: 9.8.0

Describe the bug

During its creation, Auth class is adding a callback for being notified about framework changes (observeFrameworkChanges). This callback is never cleared (there is no API to remove callbacks from the array) and causes a memory leak when using Auth with server side rendering as one instance is created for every request:

at observeFrameworkChanges (/portal/node_modules/@aws-amplify/core/lib/Platform/detectFramework.js:32:13)
at PlatformBuilder.observeFrameworkChanges (/portal/node_modules/@aws-amplify/core/lib/Platform/index.js:46:55)
at new AuthClass (/portal/node_modules/@aws-amplify/auth/lib/Auth.js:80:25)
at /portal/node_modules/aws-amplify/lib/withSSRContext.js:39:26
at Array.forEach (<anonymous>)
at withSSRContext (/portal/node_modules/aws-amplify/lib/withSSRContext.js:38:13)
at defineAmplify (webpack://webServer/./src/server/services/amplify.ts?:163:84)
at eval (webpack://webServer/./src/server/services/async.ts?:8:19)
at Layer.handle [as handle_request] (/portal/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/portal/node_modules/express/lib/router/index.js:328:13)

This seem to have been introduced with 03aa356

Expected behavior

Server side rendering does not cause memory usage to continuously grow

Reproduction steps

We have a basic Express app that does the following on every request:

const Amplify = withSSRContext({req});

and then uses Auth to authenticate users against Cognito.

Code Snippet

No response

Log output

No response

aws-exports.js

No response

Manual configuration

No response

Additional configuration

No response

Mobile Device

No response

Mobile Operating System

No response

Mobile Browser

No response

Mobile Browser Version

No response

Additional information and screenshots

No response

[cwomack]

Hello, @mathbruyen 👋. We appreciate you not only opening this issue, but providing the suspected commit as well! We'll review this internally and report back on this issue soon.

[cwomack]

@mathbruyen, this should now be fixed as of the most recent version of Amplify. Can you upgrade and verify that the memory leak no longer occurs?

The fix was actually merged in as of the v5.3.7 release, but the newer v5.3.8 has additional fixes to the Auth category that we'd recommend you have!

[mathbruyen]

The change reduced memory increase speed, I found another leak which I am reporting under a different ticket but this one seems indeed fixed. Thank you!

[cwomack]

@mathbruyen, that's great to hear that the one reported in this issue is resolved!

As for the new one, definitely open a new ticket and reference this issue in it please. We'll investigate the new one as soon as you do. Thank you for taking the time to report these!