[REQ] Is there a plan to support Alpine Linux in `dockerfile-rails` instead of the Debian OS?

[papakvy72]

Dear dockerfile-rails Team,

Regarding the issue mentioned in the title, I am searching for a gem that supports Alpine Linux in the Dockerfile and Docker Compose for development purposes. Do you have any ideas? 😄

Regards

[rubys]

A pull request that implemented alpine complete with tests would likely get merged.

Technically, the changes are not difficult. apt-get only shows up in two files.

But before those changes can be made, some research would need to be done. There are three places where packages are added:

• dockerfile-rails/lib/generators/dockerfile_generator.rb

  Lines 519 to 548 in a093495

  	def base_packages
  	packages = []
  	packages += @@packages["base"] if @@packages["base"]
  	if using_execjs?
  	if node_version == "lts"
  	packages += %w(nodejs npm)
  	else
  	packages += %w(curl)
  	end
  	end
  	if using_puppeteer?
  	packages += %w(curl gnupg)
  	end
  	# charlock_holmes. Placed here as the library itself is
  	# libicu63 in buster, libicu67 in bullseye, libiclu72 in bookworm...
  	packages << "libicu-dev" if @gemfile.include? "charlock_holmes"
  	if @gemfile.include? "webp-ffi"
  	# https://github.com/le0pard/webp-ffi#requirements
  	packages += %w(libjpeg-dev libpng-dev libtiff-dev libwebp-dev)
  	end
  	# Passenger
  	packages << "passenger" if using_passenger?
  	packages.sort.uniq
  	end

• dockerfile-rails/lib/generators/dockerfile_generator.rb

  Lines 558 to 614 in a093495

  	def build_packages
  	# start with the essentials
  	packages = %w(build-essential)
  	packages += @@packages["build"] if @@packages["build"]
  	packages += %w(nodejs npm) if (node_version == "lts") && (not using_execjs?)
  	# add databases: sqlite3, postgres, mysql
  	packages << "pkg-config" if options.sqlite3? || @sqlite3
  	packages << "libpq-dev" if options.postgresql? || @postgresql
  	packages << "freetds-dev" if options.sqlserver? || @sqlserver
  	if (options.mysql? || @mysql) && !using_trilogy?
  	packages << "default-libmysqlclient-dev"
  	end
  	# add git if needed to install gems
  	packages << "git" if @git
  	# ActiveStorage preview support
  	packages << "libvips" if @gemfile.include? "ruby-vips"
  	# Rmagick gem
  	packages += %w[pkg-config libmagickwand-dev] if @gemfile.include? "rmagick"
  	# node support, including support for building native modules
  	if using_node?
  	packages += %w(node-gyp pkg-config)
  	unless using_execjs? || using_puppeteer?
  	packages << "curl"
  	packages << "unzip" if using_bun?
  	end
  	# module build process depends on Python, and debian changed
  	# how python is installed with the bullseye release. Below
  	# is based on debian release included with the Ruby images on
  	# Dockerhub.
  	case RUBY_VERSION
  	when /^2\.7/
  	bullseye = RUBY_VERSION >= "2.7.4"
  	when /^3\.0/
  	bullseye = RUBY_VERSION >= "3.0.2"
  	when /^2\./
  	bullseye = false
  	else
  	bullseye = true
  	end
  	if bullseye
  	packages << "python-is-python3"
  	else
  	packages << "python"
  	end
  	end
  	packages.sort.uniq
  	end

• dockerfile-rails/lib/generators/dockerfile_generator.rb

  Lines 616 to 663 in a093495

  	def deploy_packages
  	packages = %w(curl) # work with the default healthcheck strategy in MRSK
  	packages += @@packages["deploy"] if @@packages["deploy"]
  	# start with databases: sqlite3, postgres, mysql
  	packages << "postgresql-client" if options.postgresql? || @postgresql
  	packages << "default-mysql-client" if options.mysql? || @mysql
  	packages << "freetds-bin" if options.sqlserver? || @sqlserver
  	packages << "libjemalloc2" if options.jemalloc? && !options.fullstaq?
  	if options.sqlite3? || @sqlite3
  	packages << "libsqlite3-0" unless packages.include? "sqlite3"
  	end
  	# litefs
  	packages += ["ca-certificates", "fuse3", "sudo"] if options.litefs?
  	# ActiveStorage preview support
  	packages << "libvips" if @gemfile.include? "ruby-vips"
  	# Rmagick gem
  	if @gemfile.include?("rmagick") || @gemfile.include?("mini_magick")
  	packages << "imagemagick"
  	end
  	# Puppeteer
  	if using_puppeteer?
  	if options.platform&.include? "amd"
  	packages << "google-chrome-stable"
  	else
  	packages += %w(chromium chromium-sandbox)
  	end
  	end
  	# Passenger
  	packages << "libnginx-mod-http-passenger" if using_passenger?
  	# nginx
  	packages << "nginx" if options.nginx? || using_passenger?
  	# sudo
  	packages << "sudo" if options.sudo?
  	if !options.procfile.blank? || (procfile.size > 1)
  	packages << "ruby-foreman"
  	end
  	packages.sort
  	end

Somebody would need to do the investigation to find out what the equivalent alpine package is for each of the packages listed there.

As an example, the Alpine equivalent of build-essential appears to be build-base.

[papakvy72]

@rubys

A pull request that implements Alpine, complete with tests, would likely get merged.

Thank you very much for the information 🙏
I'll continue waiting for that pull request to be merged into the main branch.

[rubys]

Just to clarify, I personally don't have the experience needed to identify alpine equivalents of the packages I've identified. Somebody with that experience would be the one to create a pull request. I've just outlined the what questions they would need to be prepared to answer before proceeding.

[rubys]

I spent a few minutes looking at alpine packages, and came up with a first pass:

same:
ca-certificates
chromium
curl
freedts-dev
fuse3
git
imagemagick
libpq-dev
libwebp-dev
nginx
nodejs
npm
postgresql-client
sudo

mappings:
build-essential => build-base
chromium-sandbox => chromium-chromedriver
default-libmysqlclient-dev => mysql-client
default-mysqlclient => mysql-client
freedts-bin => freedts
libicu-dev => icu-dev
libjemalloc => jemalloc-dev
libjpeg-dev => jpeg-dev
libmagickwand-dev => imagemagick-libs
libsqlite3-0 => sqlite-dev
libtiff-dev => tiff-dev
libvips => vips-dev
node-gyp => gyp
pkg-config => pkgconfig
python => python3
python-is-python3 => python3

not found:
google-chrome-stable
passenger
ruby-foreman

Based on this, I'll take a look at adding an experimental flag for alpine in the next few days.

[rubys]

Proof of concept:

# syntax = docker/dockerfile:1

FROM ruby:alpine as base

FROM base as build

RUN apk update && \
    apk add build-base git libpq-dev

RUN gem install rails
RUN rails new demo --minimal --database postgresql

FROM base

RUN apk update && \
    apk add --no-cache tzdata libpq && \
    rm /var/cache/apk/*

COPY --from=build /usr/local/bundle /usr/local/bundle
COPY --from=build /demo /demo

COPY <<-"EOF" /demo/config/routes.rb
Rails.application.routes.draw { root "rails/welcome#index" }
EOF

WORKDIR demo
ENV RAILS_ENV=production
EXPOSE 3000
CMD bin/rails server

Notes:

• git needs to be installed during the build phase
• tzdata and libpq need to be installed to deploy
• if the sqlite3 gem is included in your Gemfile, the app will fail to load

[rubys]

There apparently is a breaking change in alpine 3.19. sqlite3 works on 3.18:

# syntax = docker/dockerfile:1

FROM ruby:3-alpine3.18 as base

FROM base as build

RUN apk update && \
    apk add build-base git sqlite-dev

RUN gem install rails
RUN rails new demo --minimal

FROM base

RUN apk update && \
    apk add --no-cache tzdata sqlite-libs && \
    rm /var/cache/apk/*

COPY --from=build /usr/local/bundle /usr/local/bundle
COPY --from=build /demo /demo

COPY <<-"EOF" /demo/config/routes.rb
Rails.application.routes.draw { root "rails/welcome#index" }
EOF

WORKDIR demo
ENV RAILS_ENV=production
EXPOSE 3000
CMD bin/rails server

[rubys]

Released: https://github.com/fly-apps/dockerfile-rails/releases/tag/v1.6.0

update to the latest version, then run:

bin/rails generate dockerfile --alpine