- Use 'cheap-source-map' webpack config on low-memory machines
This results in worse quality sourcemaps in browser dev tools, but it significantly reduces memory use in our webpack build. In approximate local testing it drops from 1100mb to 590mb. This should make the rebuild process on low-memory machines much faster and less likely to trigger OOM errors.
In development, and on higher-memory machines, the higher-quality 'source-map' option is maintained.
- Disable Webpack's built-in `minimize` feature. Embroider already applies Terser after the webpack build is complete. There is no need to double-minimize the output.
- Update ember-cli-progress-ci to print to stderr instead of stdout. For some reason, pups (used by discourse_docker) buffers the stdout of commands and only prints when they are finished. stderr does not have this same limitation, so switching will mean sysadmins can see the progress of the ember build in real-time.
Given the number of variables it's hard to promise exact numbers. But, in my tests on a DO droplet with 1GB RAM (+2GB swap), this reduced the `ember build` portion of a `./launcher rebuild app` from ~50 minutes to ~15 minutes.
By default, in CI environments, Ember CLI does not output anything between "building..." and "cleaning up". Depending on configuration and hardware, Discourse asset builds can take upwards of 60s, and so this lack of output can make the build feel 'stuck'.
This commit introduces an addon which checks for CI mode, and then outputs status information periodically. The logic is very similar to Ember CLI's non-CI progress output implementation (https://github.com/ember-cli/ember-cli/blob/04a38fda2c/lib/models/builder.js#L183-L185).
