images VS features

When you visit the repository for DevContainer images, there are pre-configured list of base Docker container images for DevContainer. Let's choose the one for .NET. You can choose many different variants, but either 6.0-jammy (Ubuntu 22.04) or 6.0-focal (Ubuntu 20.04) would be yours if you prefer using Ubuntu-based images with .NET 6. Ubuntu 22.04 is set to the default base image in this post.

Dev Containers not only allow you to define which extensions should be installed and which configuration settings shall be set, but they also have something they call "Dev Container Features".

json { "name": "Ubuntu", // Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile "image": "mcr.microsoft.com/devcontainers/base:ubuntu", "features": { "ghcr.io/devcontainers/features/terraform": "latest", "ghcr.io/devcontainers/features/powershell": "latest", "ghcr.io/devcontainers/features/azure-cli": "latest" }, // 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": [], // Use 'postCreateCommand' to run commands after the container is created. // "postStartCommand": "uname -a", // "postCreateCommand": "sudo apt update; sudo apt upgrade -y;", "postAttachCommand": { "git-safe-directory": "git config --global --add safe.directory ${containerWorkspaceFolder}", "ansible_cfg_permissions": "sudo chmod o-w ${containerWorkspaceFolder}" }, "postCreateCommand": { "python": "sudo apt update; sudo apt upgrade -y; sudo apt install -y python3-pip postgresql-client; sudo python3 -m pip install --upgrade pip; pip3 install ansible python-hcl2 psycopg2-binary; ansible-galaxy collection install azure.azcollection", "populate-history": "echo 'ansible-playbook ansible/playbooks/netbox.yml' >> ~/.bash_history; echo 'terraform apply' >> ~/.bash_history; echo 'az login' >> ~/.bash_history" }, // Configure tool-specific properties. // "customizations": {}, // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root. // "remoteUser": "root" "customizations": { "vscode": { "extensions": [ "GitHub.copilot", "GitHub.copilot-labs", "GitHub.vscode-pull-request-github", "redhat.ansible", "hashicorp.terraform", "ms-toolsai.jupyter", "ms-vscode.powershell", "HashiCorp.terraform", "eamodio.gitlens", "GitHub.copilot-chat" ] } } }

there are already built docker images for common development environment. You can either use one of them, or build one from Docker file. Using a pre-built dev container doesn't mean you are only limited to that image, because you can still add other tools, which they are called features to that image. For a list of the pre-built templates check here, and for the other features that you can add check this. You don't need a Docker file, unless you want to build your dev environment step by step.

// For format details, see https://aka.ms/devcontainer.json. For config options, see the // README at: https://github.com/devcontainers/templates/tree/main/src/python { "name": "Python 3", "image": "mcr.microsoft.com/devcontainers/python:0-3.11", "features": { "ghcr.io/devcontainers/features/python:1": {} } // 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": [], // Use 'postCreateCommand' to run commands after the container is created. // "postCreateCommand": "pip3 install --user -r requirements.txt", // Configure tool-specific properties. // "customizations": {}, // Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root. // "remoteUser": "root" }

This is actually very easy. I've implemented a number of tools like this publicly but the standard doesn't limit you to public stuff. I can't emphasize enough the amount of speed we gained when we implemented this standard. https://containers.dev/features

features: While you can add everything in Dockerfile for the build, there are already pre-configured features you can optionally add. You can find the complete list of the features at here. Some examples of those features are common utilities and tools like Azure CLI, GitHub CLI and Terraform, and languages like node.js, Java, .NET, Python, etc.