Asset compile hangs on [Webpacker] Compiling assets

[Praneeta]

Trying to run NODE_ENV=production RAILS_ENV=development bundle exec rake assets:precompile --trace locally
It basically hangs at [Webpacker] Compiling assets 🎉
I cannot really tell what it's doing then.
I checked my output path packs. The files are generated but are completely empty.
Any suggestions?

I had trouble running webpacker, needed to increase the allocated memory - more about that in #1189 .

[catskull]

Compiling assets could take a very long time. How long have you let it run?

[gauravtiwari]

@Praneeta Ahh I see, could you run this locally and see what happens:

NODE_ENV=production ./bin/webpack --progress --config config/webpack/production.js

[gauravtiwari]

Also, how big is the app? Is it using angular? And how are the entry points structured i.e. what do you have in the packs folder?

[Praneeta]

@gauravtiwari Thanks for the tip on running it directly. Seems like uglifying the files is slowing (@catskull - it did not finish under 30 mins, then I stopped it.) the process.
If I comment the uglify plugin from config/production.js, it compiles in 4 mins.
My app is rather large (179 files) because I am trying to make it so that each page in the app (not a single page app) has it's own js file and there is only 1 script tag per page. But seems like this is causing the asset compile process to take forever. I will try to pull common code into chunks and have 2 script tags per page - common_chunk.js and page_specific.js

[Praneeta]

webpack.optimize.CommonsChunkPlugin was a huge help. Cut down the compile time under 5 mins. With the right config, can it get it as low as a minute.

[gauravtiwari]

Great 👍 Yeah you can try DLL plugin for further speed optimisation: https://webpack.js.org/plugins/dll-plugin/

Example: #702

[hiveer]

In my case, I have to set check_yarn_integrity: false for 'development' in config/webpacker.yml.
Otherwise you're stuck because of an integrity error.