slow deployment on heroku

Our deploys on heroku are taking quite a long time (30+ seconds) which incurs quite a bit of downtime during deployment. A second or two is acceptable, but 30 seconds is not. Any idea on how I can improve the speed of npm start? Locally it runs significantly faster…

From logs:

2016-05-18T17:39:01.756601+00:00 heroku[web.1]: Starting process with command `npm start`
2016-05-18T17:39:05.413614+00:00 app[web.1]:
2016-05-18T17:39:05.413630+00:00 app[web.1]: > react-redux-universal-hot-example@0.9.0 start /app
2016-05-18T17:39:05.413631+00:00 app[web.1]: > concurrent --kill-others "npm run start-prod"
2016-05-18T17:39:05.413632+00:00 app[web.1]:
2016-05-18T17:39:07.267232+00:00 app[web.1]: [0]
2016-05-18T17:39:07.267242+00:00 app[web.1]: [0] > react-redux-universal-hot-example@0.9.0 start-prod /app
2016-05-18T17:39:07.267243+00:00 app[web.1]: [0] > better-npm-run start-prod
2016-05-18T17:39:07.267243+00:00 app[web.1]: [0]
2016-05-18T17:39:07.465188+00:00 app[web.1]: [0] Executing script: start-prod
2016-05-18T17:39:07.431925+00:00 app[web.1]: [0] running better-npm-run in /app
2016-05-18T17:39:07.465198+00:00 app[web.1]: [0]
2016-05-18T17:39:07.465198+00:00 app[web.1]: [0] to be executed: node ./bin/server.js
2016-05-18T17:39:38.524212+00:00 app[web.1]: [0] ----
2016-05-18T17:39:38.524224+00:00 app[web.1]: [0] ==> ✅  React Redux Example is running, talking to API server on 3000.
2016-05-18T17:39:38.524843+00:00 app[web.1]: [0] ==> 💻  Open http://localhost:20037 in a browser to view the app.1

[kengoldfarb]

@jtmarmon - Here’s an example you can check out that solves the heroku boot time issue: https://github.com/kengoldfarb/react-redux-universal-hot-example/pull/1/files

I’ve got a project based on this framework with a large codebase and have also seen the heroku build times become increasingly problematic…to the point that my app is failing to boot and I get the R10 Boot Timeout error.

@Dattaya is spot-on that pre-building w/ babel-cli will fix this issue.

You’ll still have a few seconds of downtime on deploy (using free/hobby tier), but it’s nowhere near what it is with runtime transpilation.

@erikras - Is this something you’d want to incorporate back into the heroku branch?

Hope this helps!

Changes of note:

• package.json changes to the build-prod and postinstall methods so heroku will compile everything prior to boot

• Use babel-cli to compile into the dist/ directory.

• New bin/server-prod.js using pre-compiled files instead of runtime transpilation

• Update .babelrc to set aliases for some of the directories since this project doesn’t use absolute paths (otherwise node can’t find the modules after transpiling)

  • On a related note, I had to alias the redux/ directory to “myredux” to prevent confusion with the “redux” node module and then import like so:

  import {isLoaded, load as loadWidgets} from 'myredux/modules/widgets';
  

• When requiring styles, check that they’re defined and/or set a default

  • This feels a little hacky to me. There’s probably a better way to do this. I’m using more traditional styles (not component-specific) in my project so I didn’t spend much time on this part

const styles = require('./App.scss') || {};

[Dattaya]

I also had to change the entry point in webpack.prod.config.js to point to './build/client.js' instead of './src/client.js'(ofc babel loader is no longer necessary in prod.config), otherwise there was some mistake with styles. I guess alternatively it could be solved with require('./App.scss') || {};? Tangentially related to #889