Add default Dockerfiles

railties/lib/rails/generators/app_base.rb

@@ -37,6 +37,9 @@ def self.add_shared_options_for(name)
         class_option :skip_git,            type: :boolean, aliases: "-G", default: nil,
                                            desc: "Skip git init, .gitignore and .gitattributes"
 
+        class_option :skip_docker,         type: :boolean, default: nil,
+                                           desc: "Skip Dockerfile, .dockerignore and bin/docker-entrypoint"
+
         class_option :skip_keeps,          type: :boolean, default: nil,
                                            desc: "Skip source control .keep files"
 

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -70,6 +70,14 @@ def gitattributes
       template "gitattributes", ".gitattributes"
     end
 
+    def dockerfiles
+      template "Dockerfile"
+      template "dockerignore", ".dockerignore"
+
+      template "docker-entrypoint", "bin/docker-entrypoint"
+      chmod "bin/docker-entrypoint", 0755 & ~File.umask, verbose: false
+    end
+
     def version_control
       if !options[:skip_git] && !options[:pretend]
         run git_init_command, capture: options[:quiet], abort_on_failure: false
@@ -342,6 +350,12 @@ def update_active_storage
       end
       remove_task :update_active_storage
 
+      def create_dockerfiles
+        unless options[:skip_docker]
+          build(:dockerfiles)
+        end
+      end
+
       def create_config_files
         build(:config)
       end

railties/lib/rails/generators/rails/app/templates/Dockerfile.tt

@@ -0,0 +1,33 @@
+# Make sure it matches the Ruby version in .ruby-version and Gemfile
+FROM ruby:<%= Gem.ruby_version %>
+
+<% if using_node? -%>
+# Install JavaScript dependencies and libvips for Active Storage
+RUN curl -sL https://deb.nodesource.com/setup_19.x | bash -
+RUN apt-get update -qq && apt-get install -y build-essential libvips nodejs && npm install -g yarn
+
+<% elsif !skip_active_storage? -%>
+# Install libvips for Active Storage preview support
+RUN apt-get update -qq && apt-get install -y build-essential libvips
+
+<% end -%>
+WORKDIR /rails
+
+ENV RAILS_LOG_TO_STDOUT="1" \
+    RAILS_SERVE_STATIC_FILES="true" \
+    RAILS_ENV="production" \
+    BUNDLE_WITHOUT="development:test"
+
+# Install application gems
+COPY Gemfile Gemfile.lock ./
+RUN bundle install
+
+# Copy application code
+COPY . .
+
+# Precompiling assets for production without requiring secret RAILS_MASTER_KEY
+RUN SECRET_KEY_BASE_DUMMY=1 bundle exec rails assets:precompile
+
+# Entrypoint prepares database and starts app on 0.0.0.0:3000
+ENTRYPOINT ["/rails/bin/docker-entrypoint"]
+EXPOSE 3000

railties/lib/rails/generators/rails/app/templates/docker-entrypoint.tt

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Used by the Dockerfile to start the application with a prepared database
+
+# Create new or migrate existing database
+./bin/rails db:prepare
+
+# Start the server
+exec ./bin/rails server "$@"

railties/lib/rails/generators/rails/app/templates/dockerignore.tt

@@ -0,0 +1,30 @@
+# See https://docs.docker.com/engine/reference/builder/#dockerignore-file for more about ignoring files.
+
+# Ignore bundler config.
+/.bundle
+
+# Ignore all logfiles and tempfiles.
+/log/*
+/tmp/*
+<% if keeps? -%>
+!/log/.keep
+!/tmp/.keep
+
+# Ignore pidfiles, but keep the directory.
+/tmp/pids/*
+!/tmp/pids/
+!/tmp/pids/.keep
+<% end -%>
+
+# Ignore storage (uploaded files in development and any SQLite databases).
+/storage/*
+<% if keeps? -%>
+!/storage/.keep
+/tmp/storage/*
+!/tmp/storage/
+!/tmp/storage/.keep
+<% end -%>
+<% unless options.api? -%>
+
+/public/assets
+<% end -%>