Jack Moore

Email: jack(at)jmoore53.com
Project Updates

Overwrite the Overwritten

17 Jan 2020 » rails, webpacker, webpack, javascript

Why would webpacker default to overwrite my custom configs? It really just shouldn’t do that. It overwrote my custom fucking configs. A weeks worth of time spent on fixing an issue that should have never existed. F to pay respects.

It all started at one commit

The signup errors merge into master was really what did me in.. The commit was failing pipelines for who knew what reason. I was really just trying to pull it into the master branch and figured it was due to the fact that the features were not in master. boy was I wrong

So I merged and it broke. It broke big time. None of the pipelines were building, for anything.

I had no idea why. I thought the JS, using edge packages from alpine, was breaking the configuration. It wasn’t. How did I know? I have 2 other projects with the same cicd pipeline building rails projects and those had no problem. I figured it wasn’t the pipeline it was the developer, a la me. Enter debug mode.

Git add ., git commit “hotfix1”

Well… The debug process for pipelines is a little weird because I can’t view the changes unless I push them to the pipeline. A little bit of a nuasance, sure, but I needed to know why these pipelines weren’t passing. I switched branches, learned my lesson last time, and started to work.

Truthfully I thought I fatfingered something in my webpacker.yml file. It was weird though because I was able to build the assets on my local machine. Classic “it works on my machine” scenario if you asked me. Nonetheless I continued to mess with the webpack.yml config and even deleted node_modules and some of the other unneeded folders.

After everyone has gone to bed

I couldnt find the root of my problem so I went to directly to the root of it, the dockerfile itself.

I spun up a base alpine image for myself and walked through every step of my dockerfile ensuring that none of the current os packages or baseline dependencies were breaking my configuration. I passed in the project root as a volume with -v $(pwd):/app/ and everything was partially working. Through this process I ended up migrating from ruby2.6.3-alpine10 to ruby2.7.0-alpine11 thinking the alpine image was partially to blame.

After standing up the new container and working from an interactive terminal in the container, I was able to build the assets. I was shocked asking my self why this wasn’t working. I was a little upset with Gitlab, and started to put some of the blame on them and their shitty pipeline features with minimal ram. (little did I know it was my problem. also huge shoutout to Gitlab, love their services!) I then asked myself where in the process this was going wrong. I had all the info I thought I needed printing to the output, what more was going on. I looked into the webpacker documentation some more, and then I went back to my pipeline, specifically the webpacker installation portion to find this:

Step 23/33 : RUN RAILS_ENV=production rails webpacker:install
 ---> Running in fd4348b23bae
    conflict  config/webpacker.yml
Overwrite /app/config/webpacker.yml? (enter "h" for help) [Ynaqdhm] 
       force  config/webpacker.yml
Copying webpack core config
       exist  config/webpack
   identical  config/webpack/development.js
    conflict  config/webpack/environment.js
Overwrite /app/config/webpack/environment.js? (enter "h" for help) [Ynaqdhm] 
       force  config/webpack/environment.js
   identical  config/webpack/production.js
   identical  config/webpack/test.js
Copying postcss.config.js to app root directory
   identical  postcss.config.js
Copying babel.config.js to app root directory
    conflict  babel.config.js
Overwrite /app/babel.config.js? (enter "h" for help) [Ynaqdhm] 
       force  babel.config.js
Copying .browserslistrc to app root directory
   identical  .browserslistrc
The JavaScript app source directory already exists
       apply  /usr/local/bundle/bundler/gems/webpacker-c7292e9a1e15/lib/install/binstubs.rb
  Copying binstubs
       exist    bin
      create    bin/webpack
      create    bin/webpack-dev-server
File unchanged! The supplied flag value not found!  .gitignore
Installing all JavaScript dependencies [4.2.2]
         run  yarn add @rails/webpacker@4.2.2 from "."
yarn add v1.21.1

With the words conflict and force I knew immedietly it had to be webpacker overwriting my custom configurations. I decided to run cat /app/config/webpack.yml before the webpack:install and after the install and sure enough webpack:install was overwriting my customizations. I solved this pretty quickly by overwriting the overwrites running the docker copy command after the install completed. The file looks something like this (partial below):

# Compile Assets
RUN RAILS_ENV=production bundle exec rails webpacker:install
RUN RAILS_ENV=production bundle exec rails webpacker:info
RUN yarn install

# Overwrite the overwritten defaults
COPY ./config/webpacker.yml /app/config/webpacker.yml
COPY ./config/webpack/environment.js /app/config/environment.js
COPY ./config/webpack/production.js /app/config/production.js
COPY ./babel.config.js /app/babel.config.js

RUN RAILS_ENV=production bundle exec rails webpacker:compile

All about the data you get

The data output I was receiving from Gitlab was crpytic. It read something like:

 Compiling...
Compilation failed:
Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
 - configuration.entry should be an non-empty object.
   -> Multiple entry bundles are created. The key is the chunk name. The value can be a string or an array.
The command '/bin/sh -c RAILS_ENV=production bundle exec rails assets:precompile' returned a non-zero code: 1
ERROR: Job failed: exit code 1

How was I supposed to decrypt that. It wasn’t dropping my config file back to me and nor should it. It was lettimg me know there was an error with my config file, webpack.yml.

Lessons Learned

  • Request output for possible file changes when things don’t work as expected. Something may be overwriting your custom files.
  • Sometimes applications aren’t very smart, no matter how smart you think they are.
© Jack Moore