Installer for docker

README.md

@@ -20,6 +20,15 @@ Run installers to add common frameworks and libraries to your Rails app, for exa
 bin/rails thermite:install:koi
 ```
 
+Available installers:
+
+```shell
+bin/rails thermite:install:active_storage
+bin/rails thermite:install:docker
+bin/rails thermite:install:solid_cable
+bin/rails thermite:install:solid_queue
+```
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/katalyst/thermite.

lib/generators/thermite/install/docker/USAGE

@@ -0,0 +1,8 @@
+Description:
+    Installs the Katalyst Docker container setup.
+
+Example:
+    bin/rails generate thermite:install:docker
+
+    This creates a root Dockerfile, bin/docker-entrypoint, .dockerignore,
+    and removes the legacy Koi 4-era docker directory (if it exists)

lib/generators/thermite/install/docker/docker_generator.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "rails"
+require "rails/generators"
+
+module Thermite
+  module Install
+    class DockerGenerator < Rails::Generators::Base
+      def self.source_root
+        File.expand_path("templates", __dir__)
+      end
+
+      def copy_docker_files
+        template "Dockerfile.tt", "Dockerfile"
+        copy_file ".dockerignore"
+        copy_file "bin/docker-entrypoint"
+        chmod "bin/docker-entrypoint", 0o755 & ~File.umask, verbose: false
+      end
+
+      def remove_legacy_docker_directory
+        remove_dir "docker" if Pathname(destination_root).join("docker").directory?
+      end
+
+      private
+
+      def application_name
+        if defined?(Rails.application) && Rails.application
+          Rails.application.class.module_parent_name.to_s.underscore.dasherize
+        else
+          File.basename(destination_root).underscore.dasherize
+        end
+      end
+    end
+  end
+end

lib/generators/thermite/install/docker/templates/.dockerignore

@@ -0,0 +1,37 @@
+# See https://docs.docker.com/engine/reference/builder/#dockerignore-file for more about ignoring files.
+
+# Ignore git directory.
+/.git/
+
+# Ignore bundler config.
+/.bundle
+
+# Ignore all environment files (except templates).
+/.env*
+!/.env*.erb
+
+# Ignore all default key files.
+/config/master.key
+/config/credentials/*.key
+
+# Ignore all logfiles and tempfiles.
+/log/*
+/tmp/*
+!/log/.keep
+!/tmp/.keep
+
+# Ignore pidfiles, but keep the directory.
+/tmp/pids/*
+!/tmp/pids/.keep
+
+# Ignore storage (uploaded files in development and any SQLite databases).
+/storage/*
+!/storage/.keep
+/tmp/storage/*
+!/tmp/storage/.keep
+
+# Ignore assets.
+/node_modules/
+/app/assets/builds/*
+!/app/assets/builds/.keep
+/public/assets

lib/generators/thermite/install/docker/templates/Dockerfile.tt

@@ -0,0 +1,119 @@
+# syntax=docker/dockerfile:1
+# check=error=true
+
+ARG APPLICATION_NAME="<%= application_name %>"
+ARG RUBY_VERSION=4.0
+FROM ruby:$RUBY_VERSION-slim AS base
+
+ARG PACKAGES="curl libvips libjemalloc2 postgresql-client"
+
+# Rails app lives here
+WORKDIR /rails
+
+# Install base packages
+RUN apt-get update -qq && \
+    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends $PACKAGES && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
+
+ARG APPLICATION_NAME
+ARG APPLICATION_VERSION
+ARG APPLICATION_REVISION
+
+# Set production environment
+ENV APPLICATION_NAME="${APPLICATION_NAME}" \
+    BUNDLE_DEPLOYMENT="1" \
+    BUNDLE_PATH="/usr/local/bundle" \
+    BUNDLE_WITHOUT="development:test" \
+    EXECJS_RUNTIME="Disabled" \
+    RAILS_ENV="production" \
+    PUMA_SSL="1" \
+    TZ="Australia/Adelaide"
+
+# Create a rails group and user for non-privileged access
+RUN groupadd --system --gid 1000 rails && \
+    useradd rails --uid 1000 --gid 1000 --create-home --shell /bin/bash && \
+    echo "$APPLICATION_NAME ($APPLICATION_VERSION) [$APPLICATION_REVISION]" > /etc/motd && \
+    echo "PS1='\u@\${APPLICATION_NAME}-\${RAILS_ENV}:\w\$ '" >> /etc/bash.bashrc && \
+    echo "cat /etc/motd" >> /etc/bash.bashrc
+
+# Build rails gems and assets in a throw-away build stage to reduce size of final image
+FROM base AS build
+
+# Install packages needed to build gems
+ARG BUILD_PACKAGES="build-essential git libcurl4-openssl-dev libpq-dev libyaml-dev pkg-config zlib1g-dev"
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y $BUILD_PACKAGES && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
+
+# Install application gems
+COPY Gemfile Gemfile.lock ./
+RUN bundle install && \
+    rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
+    bundle exec bootsnap precompile --gemfile
+
+# Copy application code
+COPY --link . .
+
+# Precompile bootsnap code for faster boot times
+RUN bundle exec bootsnap precompile app/ lib/
+
+# If set, assets will be compiled into a subdirectory of public/ with this prefix
+ARG CDN_ASSET_PREFIX=""
+
+# Precompile assets for production
+RUN DATABASE_URL="postgresql://localhost" \
+    SECRET_KEY_BASE_DUMMY=1 \
+    ./bin/rails assets:precompile
+
+# END OF BUILD ##
+
+# Copy assets to the CDN
+FROM amazon/aws-cli:latest AS cdn
+
+ARG AWS_DEFAULT_REGION="ap-southeast-2"
+ARG CDN_ASSET_PREFIX=""
+ARG S3_ASSETS_BUCKET=""
+
+COPY --from=build /rails/public public
+RUN --mount=type=secret,id=aws-key-id,env=AWS_ACCESS_KEY_ID \
+    --mount=type=secret,id=aws-secret-key,env=AWS_SECRET_ACCESS_KEY \
+    --mount=type=secret,id=aws-session-token,env=AWS_SESSION_TOKEN \
+    if [ -n "$CDN_ASSET_PREFIX" ] && [ -n "$S3_ASSETS_BUCKET" ]; then \
+      aws s3 sync --only-show-errors --cache-control "public, max-age=31536000, immutable" \
+        public/$CDN_ASSET_PREFIX s3://$S3_ASSETS_BUCKET/$CDN_ASSET_PREFIX; \
+    fi
+
+# END OF CDN ##
+
+# Assemble everything into a single layer
+FROM base AS assemble
+
+ARG APPLICATION_VERSION
+ARG APPLICATION_REVISION
+
+COPY --link . .
+COPY --from=build /rails/tmp/cache/bootsnap tmp/cache/bootsnap
+COPY --from=cdn /aws/public public
+RUN echo $APPLICATION_VERSION > VERSION && \
+    echo $APPLICATION_REVISION > REVISION && \
+    mkdir -p db log ssl storage tmp/pids tmp/sockets && \
+    chown -R rails:rails db log ssl storage tmp
+
+# Final stage for app image
+FROM base
+
+ARG CDN_ASSET_PREFIX
+
+# Puma and Rails configuration for a small server setup with puma in single mode with 5 workers
+ENV CDN_ASSET_PREFIX=$CDN_ASSET_PREFIX \
+    WEB_CONCURRENCY=0 \
+    RAILS_MAX_THREADS=5
+
+# Assemble layers
+COPY --from=build --link "${BUNDLE_PATH}" "${BUNDLE_PATH}"
+COPY --from=assemble --link /rails .
+
+USER 1000:1000
+EXPOSE 4443
+ENTRYPOINT ["/rails/bin/docker-entrypoint"]
+CMD ["./bin/rails", "server"]

lib/generators/thermite/install/docker/templates/bin/docker-entrypoint

@@ -0,0 +1,21 @@
+#!/bin/bash -e
+
+# Enable jemalloc for reduced memory usage and latency.
+if [ -z "${LD_PRELOAD+x}" ]; then
+    LD_PRELOAD=$(find /usr/lib -name libjemalloc.so.2 -print -quit)
+    export LD_PRELOAD
+fi
+
+# If running the rails server then create or migrate existing database
+if [ "${@: -2:1}" == "./bin/rails" ] && [ "${@: -1:1}" == "server" ]; then
+  ./bin/rails db:prepare
+
+  # create a self-signed certificate for puma
+  mkdir -p ~/.ssl
+  openssl req -x509 -newkey rsa:2048 -nodes -days 730 \
+    -subj '/CN=docker/' \
+    -keyout ~/.ssl/docker.key \
+    -out ~/.ssl/docker.crt
+fi
+
+exec "${@}"

spec/generators/thermite/install/docker_generator_spec.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+require "generators/thermite/install/docker/docker_generator"
+
+RSpec.describe Thermite::Install::DockerGenerator do
+  it "completes successfully" do
+    expect { run_generator }.not_to raise_error
+  end
+
+  it "writes the Docker setup" do
+    run_generator
+
+    assert_file "Dockerfile"
+    assert_file ".dockerignore"
+    assert_file "bin/docker-entrypoint"
+  end
+
+  it "removes the legacy docker directory when present" do
+    mkdir_p File.join(destination_root, "docker")
+
+    run_generator
+
+    assert_no_file "docker"
+  end
+end