[Docker setup for Ruby gem development]

0_README.md

Example commands

Start a bash session

docker compose build && docker compose run client bash

Run tests

docker compose build && docker compose run client rspec

devcontainer.json

// FILE: .devcontainer/devcontainer.json

// For format details, see https://aka.ms/devcontainer.json. For config options, see the
// README at: https://github.com/devcontainers/templates/tree/main/src/docker-existing-docker-compose
{
	"name": "my-cool-gem",

	// Update the 'dockerComposeFile' list if you have more compose files or use different names.
	// The .devcontainer/docker-compose.yml file contains any overrides you need/want to make.
	"dockerComposeFile": [
		// "../docker-compose.yml"
		"docker-compose.yml"
	],

	// The 'service' property is the name of the service for the container that VS Code should
	// use. Update this value and .devcontainer/docker-compose.yml to the real service name.
	"service": "app",

	// The optional 'workspaceFolder' property is the path VS Code should open by default when
	// connected. This is typically a file mount in .devcontainer/docker-compose.yml
	// "workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
	"workspaceFolder": "/app",

	// Features to add to the dev container. More info: https://containers.dev/features.
	// "features": {},

	// Use 'forwardPorts' to make a list of ports inside the container available locally.
	// "forwardPorts": [],

	// Uncomment the next line if you want start specific services in your Docker Compose config.
	// "runServices": [],

	// Uncomment the next line if you want to keep your containers running after VS Code shuts down.
	// "shutdownAction": "none",

	// Uncomment the next line to run commands (on the host machine) before the container is created.
	"initializeCommand": "docker compose build",

	// Uncomment the next line to run commands when the container is created.
    // "onCreateCommand": "gem install debug solargraph", // put these gems in your Gemfile if you can

	// Uncomment the next line to run commands after the container is created.
	// "postCreateCommand": "cat /etc/os-release",

	// Configure tool-specific properties.
	"customizations": {
		"vscode": {
			"extensions": [
				"kaiwood.endwise",                       // Endwise
				"bung87.vscode-gemfile" 				 // Gemfile syntax highlighting
				"sevenc-nanashi.gemfile-lock-highlight", // Gemfile.lock syntax highlighting
				"rebornix.ruby", 						 // Ruby syntax highlighting
				"wingrunr21.vscode-ruby", 			     // Ruby syntax highlighting
				"bung87.rails", 						 // Rails syntax highlighting
				"jemmyw.rails-fast-nav", 				 // Rails fast navigation
				"sianglim.slim", 					     // Slim syntax highlighting
				"castwide.solargraph", 					 // Solargraph - Ruby language server + intellisense
			]
		}
	}

	// Uncomment to connect as an existing user other than the container default. More info: https://aka.ms/dev-containers-non-root.
	// "remoteUser": "devcontainer"
}

docker-compose.devcontainer.yml

# FILE: .devcontainer/docker-compose.yml
# NOTE This will take precedence over docker-compose.yml in the project root

services:
  # Update this to the name of the service you want to work with in your docker-compose.yml file
  app:
    build:
      context: ..
      dockerfile: .devcontainer/Dockerfile
    image: &image my-cool-gem
    container_name: *image
    env_file: ../.env
    environment:
      - SOLARGRAPH_GLOBAL_CONFIG=/root/.config/solargraph/config.yml
      - SOLARGRAPH_CACHE=/root/.cache/solargraph
    volumes:
       - ..:/app
       - /app/pkg # don't mount the pkg directory, it will be created by the build
       - ${HOME}/.config:/root/.config # mount local config, specifically for solargraph
       - ${HOME}/.cache:/root/.cache # mount local cache, specifically for solargraph
    command: ["tail", "-f", "/dev/null"]

    # Uncomment if you want to override the service's Dockerfile to one in the .devcontainer
    # folder. Note that the path of the Dockerfile and context is relative to the *primary*
    # docker-compose.yml file (the first in the devcontainer.json "dockerComposeFile"
    # array). The sample below assumes your primary file is in the root of your project.
    #
    # build:
    #   context: .
    #   dockerfile: .devcontainer/Dockerfile

    # volumes:
    #   # Update this to wherever you want VS Code to mount the folder of your project
    #   - ..:/workspaces:cached

    # Uncomment the next four lines if you will use a ptrace-based debugger like C++, Go, and Rust.
    # cap_add:
    #   - SYS_PTRACE
    # security_opt:
    #   - seccomp:unconfined

    # Overrides default command so things don't shut down after the process ends.
    # command: /bin/sh -c "while sleep 1000; do :; done"

docker-compose.yml

# FILE: docker-compose.yml (in the project root)
# NOTE: If you're using .devcontainer/docker-compose.yml then this won't be necessary

services:
  app:
    build: .
    image: &image my-cool-gem
    container_name: *image
    env_file: .env
    volumes:
       - .:/app
       - /app/pkg # don't mount the pkg directory, it will be created by the build
    command: ["tail", "-f", "/dev/null"]

Dockerfile

# FILE: Dockerfile (in the project root)
# NOTE: If you're using .devcontainer/Dockerfile then this won't be necessary

# STAGE 1: Initial setup
FROM ruby:2.6.6 as base
WORKDIR /app

# Install missing package(s)
RUN apt-get update -qq && apt-get install -yq --no-install-recommends \
    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# Prep for gem installation
# NOTE: The following `gem update` command is necessary to avoid a RubyGems warning
#       You can keep it, but it's probably not necessary for newer versions of Ruby
RUN gem update --system && gem install bundler

# STAGE 2: Install gems
# NOTE: Copy *only* the files you absolutely need for this stage, otherwise caching will become useless
FROM base as gems
COPY Gemfile Gemfile.lock *.gemspec ./
COPY lib/path/to/version.rb lib/path/to/version.rb
RUN bundle update --bundler && bundle install

# STAGE 3: Copy gems & project files and build gem executable
FROM base as final
COPY --from=gems /usr/local/bundle /usr/local/bundle
# NOTE: The following files are required for gem release and should match whatever is in the .gemspec (besides the Rakefile)
COPY Gemfile Gemfile.lock *.gemspec Rakefile ./
COPY bin                       bin
COPY exe                       exe
COPY lib                       lib

# Install the automation-client CLI
RUN bundle exec rake install
# Alternatively, you can run:
# RUN gem build *.gemspec && gem install *.gem

# Keep container running
CMD ["tail", "-f", "/dev/null"]

Dockerfile.devcontainer

# FILE: .devcontainer/Dockerfile
# NOTE This will take precedence over Dockerfile in the project root

# STAGE 1: Initial setup
FROM ruby:3.2.1 as base
WORKDIR /app

# Install missing package(s)
RUN apt-get update -qq && apt-get install -yq --no-install-recommends \
    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# Prep for gem installation
# NOTE: The following `gem update` command is necessary to avoid a RubyGems warning
#       You can keep it, but it's probably not necessary for newer versions of Ruby
RUN gem update --system && gem install bundler

# STAGE 2: Install gems
# NOTE: Copy *only* the files you absolutely need for this stage, otherwise caching will become useless
FROM base as gems
COPY Gemfile Gemfile.lock ../*.gemspec ./
COPY lib/path/to/version.rb lib/path/to/version.rb
RUN bundle update --bundler && bundle install

# Install development gems for debugging/documentation
RUN gem install debug solargraph

# STAGE 3: Copy gems & project files and build gem executable
FROM base as final
COPY --from=gems /usr/local/bundle /usr/local/bundle
COPY .. /app

# Install the automation-client CLI
RUN bundle exec rake install
# Alternatively, you can run:
# RUN gem build *.gemspec && gem install *.gem

# Keep container running
CMD ["tail", "-f", "/dev/null"]

my_cool_gem.gemspec

  # Specify which files should be added to the gem when it is released
  # NOTE: This should match whatever is added in Stage 3 of the Dockerfile (besides the Rakefile, which isn't necessary for release)
  spec.files = Dir.glob("{bin,exe,lib}/**/*") + Dir.glob("*.gemspec") + ["Gemfile", "Gemfile.lock"]