Access your host's Docker install from inside a container when using Docker Compose. Installs Docker extension in the container along with needed CLIs.

Dev containers can be useful for all types of applications including those that also deploy into a container based-environment. While you can directly build and run the application inside the dev container you create, you may also want to test it by deploying a built container image into your local Docker Desktop instance without affecting your dev container.

This example illustrates how you can do this by running CLI commands and using the Docker VS Code extension right from inside your dev container. It installs the Docker extension inside the container so you can use its full feature set with your project.

The included .devcontainer/Dockerfile can be altered to work with other Debian/Ubuntu-based container images such as node or python.

FROM mcr.microsoft.com/devcontainers/javascript-node:18-bullseye

Note: If you need to mount folders within the dev container into your own containers using docker-outside-of-docker, you may find Docker in Docker meets your needs better in some cases (despite a potential performance penalty).

In some cases, you may want to be able to mount the local workspace folder into a container you create while running from inside the dev container (e.g. using -v from the Docker CLI). The issue is that, with "Docker outside of Docker", containers are always created on the host. So, when you bind mount a folder into any container, you'll need to use the host's paths.

In GitHub Codespaces, the workspace folder is available in the same place on the host as it is in the container, so you can bind workspace contents as you would normally.

However, for most Dev Container spec supporting tools, this is typically not the case. A simple way to work around this is to put ${localWorkspaceFolder} in an environment variable that you then use when doing bind mounts inside the container.

Add the following to .devcontainer.json:

"remoteEnv": { "LOCAL_WORKSPACE_FOLDER": "${localWorkspaceFolder}" }

Then reference the env var when running Docker commands from the terminal inside the container.

docker run -it --rm -v "${LOCAL_WORKSPACE_FOLDER//\\/\/}:/workspace" debian bash

By default, web frameworks and tools often only listen to localhost inside the container. As a result, we recommend using the forwardPorts property to make these ports available locally.

"forwardPorts": [9000]

The ports property in docker-compose.yml publishes rather than forwards the port. This will not work in a cloud environment like Codespaces and applications need to listen to * or 0.0.0.0 for the application to be accessible externally. Fortunately the forwardPorts property does not have this limitation.

Note: This file was auto-generated from the devcontainer-template.json. Add additional notes to a NOTES.md.