[Solved: Upgrade to Rails 6] Spring app starts to use 100% CPU after I run some specs

[ndbroadbent]

Posting for posterity / Google indexing

I'm using Rails 5.2.3, Spring 2.1.0, spring-watcher-listen 2.0.1, on macOS Catalina 10.15.1.

The spring app process starts using 99%-100% CPU after I run some specific tests. I started spring server, and found this in the logs:

[2019-12-07 23:35:43 +0700] [63351] [application:test] forked 63361
[2019-12-07 23:35:43 +0700] [63316] [application_manager:test] got worker pid 63361
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/Current/Resources

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0/Resources

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/Current/Libraries

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0/Libraries

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/Current/Internet Plug-Ins

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0/Internet Plug-Ins

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/Current/XPCServices

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0/XPCServices

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
        ** ERROR: directory is already being watched! **

        Directory: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/Current/Helpers

        is already being watched through: /path/to/my/app/node_modules/puppeteer/.local-chromium/mac-686378/chrome-mac/Chromium.app/Contents/Frameworks/Chromium Framework.framework/Versions/78.0.3882.0/Helpers

        MORE INFO: https://github.com/guard/listen/wiki/Duplicate-directory-errors
[2019-12-07 23:36:05 +0700] [63351] [application:test] 63361 exited with 0

So it seems like this is potentially the same issue as rails#32700 - "lot of 'is already being watched through' messages when using rails console if using node_modules"

The strange thing is that these specs don't use puppeteer or Chromium. These errors also don't appear when I run a lot of other specs, and the 100% CPU usage doesn't happen. So I'm not sure why some specific specs are causing node_modules to be watched.

I read through the wiki article for "Duplicate directory errors", and it sounds like this could be the cause for the high CPU usage.

I found rails#33822 - "Do not watch parent directory of dirs". This sounds promising! I saw that this commit never made it into the 5-2-stable branch, so it's not available in my current version of Rails: 5.2.3.

So it sounds like this issue will be solved after I upgrade to Rails 6. I just wanted to post this issue so that Google will pick it up, in case anyone else runs into it on Rails 5.x.

Related issues:

• Spring hangs a lot #396 - Spring hangs a lot
• Spring app eating cpu in background #253 - Spring app eating cpu in background
• spring-watcher-listen#15 - Some way to ignore files on Rails 5...
• listen#338 - Ignore node_modules directory by default