Shakapacker slowing down system test even with assets precompiled

[rioug]

We are moving to Shakapacker, but we run into a weird issue where Shakapacker is slowing down our system test to the point a lot of them fail on CI. We precompile our assets for system test, so that they don't need to be compiled by Shakapacker. It's working as expected, Shakapacker is not compiliing assests on each request. That said, Shackacker checking if it needs to compile something seems to be slowing down the request enough that it results in lost of test failing.

I couldn't find any related issue, I ended creating a separate config file to disable compile on ci as suggested here : #402 and it works fine now.

I noticed the issue on Shakapacker 6 and 7, I am yet to upgrade to version 8 and 9. I am wondering if it's an known problem, or if maybe I am doing something wrong. Here is the config I am using : https://github.com/rioug/openfoodnetwork/blob/10298-upgrade-to-shakapaker/config/webpacker.yml and ci config : https://github.com/rioug/openfoodnetwork/blob/10298-upgrade-to-shakapaker/config/ci_webpacker.yml

[justin808]

The number one thing comes to mind is if you don't have the system set up correctly to compile your JavaScript files before CI runs. So, what can happen is that with every system test you're going to trigger compilation.

Make sure this setting in shakapacker.yml is false:
compile | boolean | env-specific | Compile assets on-demand when requests are made

and make sure to run bin/shakapacker to compile at the beginning of CI.

[justin808]

BTW - if compile is true, either compiler_strategy is used to determine if the assets need compiling.

[rioug]

Thanks for the quick response !

Sorry I should have clarified, we used to have compile: true for the test environment using Webpacker, and we pre compile assets on CI so that we don't trigger compilation on every request. So we had the best of both world, no need to precompile when doing dev work on our machine, and no need to have a different setting for CI.

The number one thing comes to mind is if you don't have the system set up correctly to compile your JavaScript files before CI runs. So, what can happen is that with every system test you're going to trigger compilation.

Yeah I though about that, we run assets:precompile before CI which run shakapacker, I confirmed it's working as expected, and I can see "[Shakapacker] Everything's up-to-date. Nothing to do" message in the CI logs.
I'll have a play with compiler_strategy see if that solve the problem, otherwise I'll just stick with the different config file for CI.

[rioug]

Using compiler_strategy: mtime fix the issue, it looks like using digest is too costly on the CI machines. Thanks for the pointers !