Dedicated Docker Compose service for the remote interpreter

Things to point out:
- No need for .ruby-version (it's specified on Gemfile instead)
- Some adjustment on puma.rb and notes (TODOs) on other files
- Dedicated environment file for development
Interesting links:
- docker/compose#1393
- https://www.alanvardy.com/post/puma-server-not-loading
- https://webpack.js.org/guides/environment-variables/

Author: willianantunes

.dockerignore

@@ -0,0 +1,14 @@
+# https://docs.docker.com/engine/reference/builder/#dockerignore-file
+# Block everything
+*
+# Allowed files and directories
+!app
+!bin
+!config
+!db
+!lib
+!config.ru
+!Gemfile
+!Gemfile.lock
+!tmp/.keep
+!tmp/pids/.keep

.env.development

@@ -0,0 +1,19 @@
+##################
+#### HTTP
+PORT=3000
+
+##################
+#### Rails
+RAILS_ENV=development
+
+##################
+#### Web Server
+RAILS_MIN_THREADS=4
+RAILS_MAX_THREADS=20
+WEB_CONCURRENCY=0
+PIDFILE=tmp/pids/server.pid
+
+##################
+#### Ruby
+# https://bugs.ruby-lang.org/issues/14850
+TZ=UTC

.gitignore

@@ -1,6 +1,6 @@
 
-# Created by https://www.toptal.com/developers/gitignore/api/rails,ruby,jetbrains+all
-# Edit at https://www.toptal.com/developers/gitignore?templates=rails,ruby,jetbrains+all
+# Created by https://www.toptal.com/developers/gitignore/api/rails,jetbrains+all
+# Edit at https://www.toptal.com/developers/gitignore?templates=rails,jetbrains+all
 
 ### JetBrains+all ###
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
@@ -108,8 +108,11 @@ pickle-email-*.html
 # Ignore all logfiles and tempfiles.
 /log/*
 /tmp/*
+/tmp/pids/*
 !/log/.keep
 !/tmp/.keep
+!/tmp/pids
+!/tmp/pids/.keep
 
 # TODO Comment out this rule if you are OK with secrets being uploaded to the repo
 config/initializers/secret_token.rb
@@ -120,8 +123,8 @@ config/master.key
 
 # dotenv, dotenv-rails
 # TODO Comment out these rules if environment variables can be committed
+#.env.*
 .env
-.env.*
 
 ## Environment normalization:
 /.bundle
@@ -161,62 +164,7 @@ yarn-debug.log*
 /storage/*
 !/storage/.keep
 
-### Ruby ###
-*.gem
-/.config
-/InstalledFiles
-/pkg/
-/spec/reports/
-/spec/examples.txt
-/test/tmp/
-/test/version_tmp/
-/tmp/
-
-# Used by dotenv library to load environment variables.
-# .env
-
-# Ignore Byebug command history file.
-
-## Specific to RubyMotion:
-.dat*
-.repl_history
-build/
-*.bridgesupport
-build-iPhoneOS/
-build-iPhoneSimulator/
-
-## Specific to RubyMotion (use of CocoaPods):
-#
-# We recommend against adding the Pods directory to your .gitignore. However
-# you should judge for yourself, the pros and cons are mentioned at:
-# https://guides.cocoapods.org/using/using-cocoapods.html#should-i-check-the-pods-directory-into-source-control
-# vendor/Pods/
-
-## Documentation cache and generated files:
-/.yardoc/
-/_yardoc/
-/doc/
-/rdoc/
-
-/.bundle/
-/lib/bundler/man/
-
-# for a library or gem, you might want to ignore these files since the code is
-# intended to run in multiple environments; otherwise, check them in:
-# Gemfile.lock
-# .ruby-version
-# .ruby-gemset
-
-# unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
-
-# Used by RuboCop. Remote config files pulled in from inherit_from directive.
-# .rubocop-https?--*
-
-### Ruby Patch ###
-# Used by RuboCop. Remote config files pulled in from inherit_from directive.
-# .rubocop-https?--*
-
-# End of https://www.toptal.com/developers/gitignore/api/rails,ruby,jetbrains+all
+# End of https://www.toptal.com/developers/gitignore/api/rails,jetbrains+all
 
 # Ignore master key for decrypting credentials and more.
 /config/master.key

DockerfileForDev

@@ -0,0 +1,19 @@
+FROM timbru31/ruby-node:2.7
+
+RUN groupadd --system app-user && adduser --system --ingroup app-user app-user
+
+WORKDIR /app
+
+RUN chown app-user:app-user /app
+
+COPY Gemfile Gemfile.lock ./
+
+RUN bundle install
+
+USER app-user
+
+COPY --chown=app-user:app-user . ./
+
+# https://puma.io/puma/
+# Without arguments, puma will look for a rackup (.ru) file in the current working directory called config.ru
+CMD bundle exec puma

config/environments/production.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
@@ -11,7 +13,7 @@
   config.eager_load = true
 
   # Full error reports are disabled and caching is turned on.
-  config.consider_all_requests_local       = false
+  config.consider_all_requests_local = false
 
   # Ensures that a master key has been made available in either ENV["RAILS_MASTER_KEY"]
   # or in config/master.key. This key is used to decrypt credentials (and other encrypted files).
@@ -38,10 +40,11 @@
 
   # Use the lowest log level to ensure availability of diagnostic information
   # when problems arise.
+  # TODO: Use ENV for this setup
   config.log_level = :debug
 
   # Prepend all log lines with the following tags.
-  config.log_tags = [ :request_id ]
+  config.log_tags = [:request_id]
 
   # Use a different cache store in production.
   # config.cache_store = :mem_cache_store
@@ -64,7 +67,7 @@
   # require 'syslog/logger'
   # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
 
-  if ENV["RAILS_LOG_TO_STDOUT"].present?
+  if ENV['RAILS_LOG_TO_STDOUT'].present?
     logger           = ActiveSupport::Logger.new(STDOUT)
     logger.formatter = config.log_formatter
     config.logger    = ActiveSupport::TaggedLogging.new(logger)

config/puma.rb

@@ -1,38 +1,36 @@
+# frozen_string_literal: true
+
 # Puma can serve each request in a thread from an internal thread pool.
 # The `threads` method setting takes two numbers: a minimum and maximum.
 # Any libraries that use thread pools should be configured to match
 # the maximum value specified for Puma. Default is set to 5 threads for minimum
 # and maximum; this matches the default thread size of Active Record.
-#
-max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
-min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
+max_threads_count = ENV.fetch('RAILS_MAX_THREADS') { 5 }
+min_threads_count = ENV.fetch('RAILS_MIN_THREADS') { max_threads_count }
 threads min_threads_count, max_threads_count
 
 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
-#
-port        ENV.fetch("PORT") { 3000 }
+port ENV.fetch('PORT') { 3000 }
 
 # Specifies the `environment` that Puma will run in.
-#
-environment ENV.fetch("RAILS_ENV") { "development" }
+environment ENV.fetch('RAILS_ENV') { 'development' }
 
 # Specifies the `pidfile` that Puma will use.
-pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
+pidfile ENV.fetch('PIDFILE') { 'tmp/pids/server.pid' }
 
 # Specifies the number of `workers` to boot in clustered mode.
 # Workers are forked web server processes. If using threads and workers together
 # the concurrency of the application would be max `threads` * `workers`.
 # Workers do not work on JRuby or Windows (both of which do not support
 # processes).
-#
-# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+number_of_workers = ENV.fetch('WEB_CONCURRENCY') { 0 }
+workers number_of_workers
 
 # Use the `preload_app!` method when specifying a `workers` number.
 # This directive tells Puma to first boot the application and load code
 # before forking the application. This takes advantage of Copy On Write
 # process behavior so workers use less memory.
-#
-# preload_app!
+preload_app! if number_of_workers.positive?
 
 # Allow puma to be restarted by `rails restart` command.
 plugin :tmp_restart

docker-compose.yaml

@@ -1,5 +1,14 @@
 version: "2.4"
 services:
+  remote-interpreter:
+    build:
+      context: .
+      dockerfile: DockerfileForDev
+    env_file: .env.development
+    ports:
+      - "8000:3000"
+    volumes:
+      - .:/app
   word-suggestion:
     image: willianantunes/runner-said-no-one-ever
     environment: