How to use the command devcontainer (with examples)

The devcontainer command allows developers to use Docker containers as development environments. This provides a consistent and reproducible environment for building, testing, and debugging applications. With the devcontainer command, developers can easily create, run, apply templates, execute commands, build images, and open Dev Containers in Visual Studio Code.

Use case 1: Create and run a Dev Container

Code:

devcontainer up

Motivation: Creating and running a Dev Container allows developers to quickly set up a development environment with all the necessary dependencies and tools pre-installed. This can save time and ensure consistent development environments across different machines.

Explanation:

• The devcontainer command is followed by up to create and run a Dev Container.
• No additional arguments are required for this use case.

Example output:

Creating Dev Container...
Successfully created and started Dev Container.

Use case 2: Apply a Dev Container Template to a workspace

Code:

devcontainer templates apply --template-id template_id --template-args template_args --workspace-folder path/to/workspace

Motivation: Applying a Dev Container Template to a workspace allows developers to easily configure a Dev Container based on predefined templates. This can help standardize development environments across teams and projects.

Explanation:

• The devcontainer command is followed by templates apply to apply a Dev Container Template.
• --template-id specifies the ID of the template to apply.
• --template-args specifies any template arguments if required by the template.
• --workspace-folder specifies the path to the workspace folder.

Example output:

Applying Dev Container template...
Successfully applied Dev Container template to the workspace.

Use case 3: Execute a command on a running Dev Container in the current workspace

Code:

devcontainer exec command

Motivation: Running commands on a running Dev Container allows developers to perform various tasks within the containerized environment, such as running tests, building the project, or starting a development server.

Explanation:

• The devcontainer command is followed by exec to execute a command on a running Dev Container.
• command is the command to be executed within the Dev Container.

Example output:

Executing command 'npm test' on running Dev Container...
All tests passed.

Use case 4: Build a Dev Container image from devcontainer.json

Code:

devcontainer build path/to/workspace

Motivation: Building a Dev Container image from a devcontainer.json file allows developers to customize and package a development environment as a Docker image. This image can then be shared across team members or deployed to different development environments.

Explanation:

• The devcontainer command is followed by build to build a Dev Container image.
• path/to/workspace specifies the path to the workspace folder containing the devcontainer.json file.

Example output:

Building Dev Container image...
Successfully built Dev Container image: dev-container:latest

Use case 5: Open a Dev Container in VS Code

Code:

devcontainer open path/to/workspace

Motivation: Opening a Dev Container in Visual Studio Code allows developers to directly work within the containerized environment, leveraging the benefits of the Docker-powered development environment and the rich features of VS Code.

Explanation:

• The devcontainer command is followed by open to open a Dev Container in VS Code.
• path/to/workspace specifies the path to the workspace folder. This argument is optional and if not provided, the current workspace will be used.

Example output:

Opening Dev Container in VS Code...
Successfully opened Dev Container in VS Code.

Use case 6: Read and print the configuration of a Dev Container from devcontainer.json

Code:

devcontainer read-configuration

Motivation: Reading and printing the configuration of a Dev Container from devcontainer.json allows developers to check the current configuration and verify the settings defined in the file.

Explanation:

• The devcontainer command is followed by read-configuration to read and print the configuration.
• No additional arguments are required for this use case.

Example output:

Reading and printing Dev Container configuration...
{
  "name": "Dev Container",
  "dockerFile": "Dockerfile",
  "runArgs": ["--privileged"],
  "extensions": ["ms-vscode.vscode-extension-pack"]
}

Conclusion:

The devcontainer command provides developers with a powerful tool for creating, managing, and working with Docker containers as development environments. Whether it’s setting up a Dev Container, applying templates, executing commands, building images, or opening containers in VS Code, the devcontainer command streamlines the development process and enhances collaboration across teams.