Docker serves as a platform to construct, deliver, and operate applications within containers. A container represents a compact, independent, and executable software package encompassing all essential components for running an application—code, runtime, libraries, system tools, and configurations. Docker simplifies the bundling of an application and its dependencies into a unified container, facilitating deployment across various environments compatible with Docker.
Ruby is an open-source web application development framework rooted in Ruby, and is widely adopted by major companies like GitHub, Shopify, Airbnb, and Twitch.
Its utilization underscores the framework’s effectiveness in building robust and scalable web products.
In this article, we’ll guide you on Dockerizing a Ruby application and the initial steps involved.
So, let’s dive right into it.
What is Docker?
Docker is a tool that enables developers to define the operating system configuration for running an application. It introduces an abstraction layer called a container, encapsulating the virtual environment’s configurations. Docker’s widespread adoption is due to its ability to package all stack dependencies into a single container unit.
Also read: Revolutionizing Containerization and Simplifying Deployment
Advantages of Using Docker for Software Development
For those consistently seeking ways to enhance productivity and improve the software development experience, Docker provides five key benefits:
- Cross-Environment Consistency
Docker empowers you to encapsulate your application, making it effortlessly portable across various environments. It ensures seamless functionality in all environments and on any Docker-capable machine.
- Effortless Team Expansion
New developers should no longer be burdened with lengthy setup documents. Docker streamlines this process, allowing all team members to run your multi-service application on their workstations with automated, repeatable, and efficient commands. Within minutes, everything works seamlessly.
- Flexibility with Technology Choices
Whether you’re a startup or a monolingual shop, Docker’s container isolation liberates developers to experiment with new languages and frameworks. Share a Docker image, eliminating concerns about setting up specific technologies for others.
- Build Once, Deploy Many Times
With applications housed in pre-built Docker images, starting them takes mere milliseconds. This ease of scaling simplifies the process of moving images across hosts. Tasks like installing dependencies only occur at the initial build, ensuring quick and predictable deployments.
- Collaboration Between Developers and Operation Managers
Docker serves as an abstraction, fostering collaboration between developers and operation managers with the common goal of deploying an application. Distribute applications without requiring in-depth knowledge of environment configurations. Docker’s toolset simplifies image distribution and tracking changes and enables public or private sharing.
Docker revolutionizes the software development and deployment process by offering consistency, simplicity, flexibility, scalability, and collaborative efficiency.
Install Docker In Ruby Applications
Step 1: Installing Docker
Refer to the official installation manuals for your operating system.
For Linux:
sudo apt-get install docker
For macOS: Install Docker Desktop on Mac
brew install docker
For Windows: Download it from here. Install Docker Desktop on Windows
Step 2: Managing Multiple Environments with Docker
In real projects, organizing images for various environments is essential. Production images may not need a text editor, and test suite images might differ in database configurations. Docker images serve as a bootstrap for your application.
Creating Docker Images
To create an image, you can use a Dockerfile. For instance, to run a container with Ubuntu:
- FROM ubuntu
CMD echo “I am a container running Ubuntu”
To Dockerize your app, you specify the operating system and tools in the Dockerfile. Official images provide a basic set of tools for each stack. For example:
- FROM ruby
RUN ruby -e “p ENV”
Images can be versioned, like (current version):
FROM ruby:3.3.0
Step 3: Building Docker Images
Build the image locally using:
docker build .
This command downloads and builds the image. Subsequent builds are cached for efficiency.
- Checking Docker Images
Use ‘docker images’ to see available images on your computer.
docker images
- Reducing Image Size
Consider using a more compact base image like Alpine Linux:
FROM ruby:alpine
RUN ruby -e “p ENV”
After building, the image size is significantly reduced.
Step 4: Working with Containers
There are different ways to synchronize your project into a container:
- Copying Resources: Useful for self-contained application deployment.
- Using Volumes: Helpful for changing container files without rebuilding the image.
- Linking Features: Useful for keeping containers compact.
- Running Docker Containers
After building an image, reuse it and run commands within the container:
docker run -it ruby:alpine bash -c “ruby -e ‘3.times {|i| puts i}‘”
- Build Options
Tag images for easier reuse:
docker build -t digitalresults/sinatra .
Step 5: Deploying your Dockerized application
Deploying your Dockerized application is a straightforward process, requiring just a single command to initiate the application on the target machine. Assuming Docker is installed on the host, you can use the “docker run” command to create and start a Docker container.
Here’s the deployment command breakdown:
docker run -t -p 3000:3010 clogeny/my-RoR-app
Explanation of the command:
docker run: Initiates the creation and execution of a Docker container.
- -t: This flag is used to display the standard output (stdout) and standard error (stdErr) on the command line, providing real-time feedback.
- -p 3000:3010: The -p flag is crucial for mapping container ports to host ports. In this case, it maps container port 3000 to host port 3010, ensuring the application is accessible externally.
- clogeny/my-RoR-app: Specifies the image to be used for the container. In this example, it uses the “my-RoR-app” image, which was previously uploaded to the repository.
Executing this command will swiftly bring the Docker container to life. Within seconds, your Dockerized application will be up and running.
To access the application, simply navigate to the following URL in your web browser:
https://localhost:3010
Congratulations!
Your Docker containerized application is now deployed and accessible through the specified URL. This streamlined deployment process is one of the key advantages of using Docker, providing efficiency and ease of management for your applications.
Step 6: Working with Docker Compose
Docker Compose helps compose and manage multiple containers. It simplifies working with containerized toolboxes.
- Docker Registry: Docker Registry is the official platform for storing and sharing Docker images.
- Pushing and Pulling Images: Use docker push to share your updated image. Use docker pull to download images from the repository.
- Docker in Production: Consider using Docker Compose, Kubernetes, Docker Swarm, Apache Mesos, or OpenShift for container orchestration in production.
Final Say
Integrating Docker into Ruby applications continues to be a game-changer for developers, offering streamlined development, efficient deployment, and improved scalability. The combination of Docker and Ruby empowers developers to create consistent and isolated environments, ensuring that applications run seamlessly across different stages of the development lifecycle.
By encapsulating Ruby applications into Docker containers, developers benefit from a portable, reproducible, and easily deployable solution. The step-by-step guide provided insights into key aspects of Dockerizing Ruby applications, from understanding Docker fundamentals to optimizing image sizes and deploying applications effortlessly.
FAQs on Docker In Ruby Applications
1: Why should I use Docker in my Ruby applications?
Docker provides a consistent and isolated environment for Ruby applications, ensuring they run reliably across different systems. It simplifies the deployment process, facilitates version control of dependencies, and enhances scalability.
2: How does Docker help manage dependencies in a Ruby application?
Docker allows you to package all the dependencies of your Ruby application into a single container, eliminating compatibility issues and ensuring a consistent environment across development, testing, and production.
3: Can I optimize the size of Docker images for Ruby applications?
Yes, Docker allows you to optimize image size. Choosing a minimal base image, like Alpine Linux, and carefully crafting your Dockerfile can significantly reduce the size of the final Docker image.
4: What are the key benefits of using Docker for Ruby development in 2024?
The key benefits include consistent environments, simplified deployment, scalability, efficient management of dependencies, and the ability to work seamlessly across various stages of the development lifecycle.
