Deployment

Webpacker hooks up a new webpacker:compile task to assets:precompile, which gets run whenever you run assets:precompile. If you are not using Sprockets webpacker:compile is automatically aliased to assets:precompile. Remember to set NODE_ENV environment variable to production during deployment or when running the rake task.

The javascript_pack_tag and stylesheet_pack_tag helper method will automatically insert the correct HTML tag for compiled pack. Just like the asset pipeline does it.

By default the output will look like this in different environments:

  <!-- In development mode with webpack-dev-server -->
  <script src="http://localhost:8080/calendar-0bd141f6d9360cf4a7f5.js"></script>
  <link rel="stylesheet" media="screen" href="http://localhost:8080/calendar-dc02976b5f94b507e3b6.css">
  <!-- In production or development mode -->
  <script src="/packs/js/calendar-0bd141f6d9360cf4a7f5.js"></script>
  <link rel="stylesheet" media="screen" href="/packs/css/calendar-dc02976b5f94b507e3b6.css">

Heroku

In order for your Webpacker app to run on Heroku, you’ll need to do a bit of configuration before hand.

heroku create my-webpacker-heroku-app
heroku addons:create heroku-postgresql:hobby-dev
heroku buildpacks:add heroku/nodejs
heroku buildpacks:add heroku/ruby
git push heroku master

We’re essentially doing the following here:

• Creating an app on Heroku
• Creating a Postgres database for the app (this is assuming that you’re using Heroku Postgres for your app)
• Adding the Heroku NodeJS and Ruby buildpacks for your app. This allows the npm or yarn executables to properly function when compiling your app - as well as Ruby.
• Pushing our code to Heroku and kicking off the deployment

Nginx

Webpacker doesn’t serve anything in production. You’re expected to configure your web server to serve files in public/ directly.

Some servers support sending precompressed versions of files when they’re available. For example, nginx offers a gzip_static directive that serves files with the .gz extension to supported clients. With an optional module, nginx can also serve Brotli compressed files with the .br extension (see below for installation and configuration instructions).

Here’s a sample nginx site config for a Rails app using Webpacker:

upstream app {
  # server unix:///path/to/app/tmp/puma.sock;
}

server {
  listen 80;
  server_name www.example.com;
  root /path/to/app/public;

  location @app {
    proxy_pass http://app;
    proxy_redirect off;

    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
  }

  location / {
    try_files $uri @app;
  }

  location = /favicon.ico { access_log off; log_not_found off; }
  location = /robots.txt  { access_log off; log_not_found off; }

  location ~ /\.(?!well-known).* {
    deny all;
  }

  location ~ ^/(assets|packs)/ {
    gzip_static on;
    brotli_static on; # Optional, see below
    expires max;
    add_header Cache-Control public;
  }
}

Installing the ngx_brotli module

If you want to serve Brotli compressed files with nginx, you will need to install the nginx_brotli module. Installation instructions from source can be found in the official google/ngx_brotli git repository. Alternatively, depending on your platform, the module might be available via a pre-compiled package.

Once installed, you need to load the module. As we want to serve the pre-compressed files, we only need the static module. Add the following line to your nginx.conf file and reload nginx:

load_module modules/ngx_http_brotli_static_module.so;

Now, you can set brotli_static on; in your nginx site config, as per the config in the last section above.

CDN

Webpacker out-of-the-box provides CDN support using your Rails app config.action_controller.asset_host setting. If you already have CDN added in your Rails app you don’t need to do anything extra for Webpacker, it just works.

Capistrano

Assets compiling on every deployment even if JavaScript and CSS files are not changed

Make sure you have public/packs and node_modules in :linked_dirs

append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "public/packs", ".bundle", "node_modules"

If you have node_modules added to :linked_dirs you’ll need to run yarn install before deploy:assets:precompile, so you can add this code snippet at the bottom deploy.rb

before "deploy:assets:precompile", "deploy:yarn_install"
namespace :deploy do
  desc "Run rake yarn install"
  task :yarn_install do
    on roles(:web) do
      within release_path do
        execute("cd #{release_path} && yarn install --silent --no-progress --no-audit --no-optional")
      end
    end
  end
end

If you use nvm to manage node versions for your deployment user, use the below snippet instead:

before "deploy:assets:precompile", "deploy:yarn_install"
namespace :deploy do
  desc "Run rake yarn install"
  task :yarn_install do
    on roles(:web) do
      within release_path do
        execute("source ~/.nvm/nvm.sh && cd #{release_path} && yarn install --silent --no-progress --no-audit --no-optional")
      end
    end
  end
end

The source ~/.nvm/nvm.sh is required because nvm is not automatically loaded in non-interactive shells.