Try Out Development Containers: .NET Core

A development container is a running Docker container with a well-defined tool/runtime stack and its prerequisites. You can try out development containers with GitHub Codespaces or Visual Studio Code Remote - Containers.

This is a sample project that lets you try out either option in a few easy steps. We have a variety of other vscode-remote-try-* sample projects, too.

Note: If you already have a Codespace or dev container, you can jump to the Things to try section.

Setting up the development container

GitHub Codespaces

Follow these steps to open this sample in a Codespace:

1. Click the Code drop-down menu and select the Open with Codespaces option.
2. Select + New codespace at the bottom on the pane.

For more info, check out the GitHub documentation.

VS Code Remote - Containers

Follow these steps to open this sample in a container using the VS Code Remote - Containers extension:

1. If this is your first time using a development container, please ensure your system meets the pre-reqs (i.e. have Docker installed) in the getting started steps.

2. To use this repository, you can either open the repository in an isolated Docker volume:

   • Press F1 and select the Remote-Containers: Try a Sample... command.
   • Choose the ".NET Core" sample, wait for the container to start, and try things out!

     Note: Under the hood, this will use the Remote-Containers: Clone Repository in Container Volume... command to clone the source code in a Docker volume instead of the local filesystem. Volumes are the preferred mechanism for persisting container data.

   Or open a locally cloned copy of the code:

   • Clone this repository to your local filesystem.
   • Press F1 and select the Remote-Containers: Open Folder in Container... command.
   • Select the cloned copy of this folder, wait for the container to start, and try things out!

3. If you want to enable HTTPS, see enabling HTTPS to reuse your local development cert in the container.

Things to try

Once you have this sample opened, you'll be able to work with it like you would locally.

Note: This container runs as a non-root user with sudo access by default. Comment out "remoteUser": "vscode" in .devcontainer/devcontainer.json if you'd prefer to run as root.

Some things to try:

1. Restore Packages: When notified by the C# extension to install packages, click Restore to trigger the process from inside the container!

2. Edit:

   • Open Program.cs
   • Try adding some code and check out the language features.

3. Terminal: Press ctrl+shift+` and type dotnet --version and other Linux commands from the terminal window.

4. Build, Run, and Debug:

   • Open Program.cs
   • Add a breakpoint (e.g. on line 21).
   • Press F5 to launch the app in the container.
   • Once the breakpoint is hit, try hovering over variables, examining locals, and more.
   • Continue (F5). You can connect to the server in the container by clicking "Open in Browser" next to port 5000 in the 'Ports' view (you can get to the 'Ports' view by clicking on the "2" in the status bar, which means your app has 2 forwarded ports).

   Note: In Remote - Containers, you can access your app at http://localhost:5000 in a local browser. But in a browser-based Codespace, you must click the link from the Ports view so that the service handles port forwarding in the browser and generates the correct URL.

5. Rebuild or update your container (Currently, only containers with the VS Code Remote - Containers extension can be rebuilt.)

   You may want to make changes to your container, such as installing a different version of a software or forwarding a new port. You'll rebuild your container for your changes to take effect.

   Forward a port statically: As an example change, let's forward a port statically in the .devcontainer/devcontainer.json file.

   Note: Remote-Containers and Codespaces also take care of dynamic port forwarding, but there may be instances in which we want to statically declare a forwarded port.

   • Open the .devcontainer/devcontainer.json file.
   • Uncomment the forwardedPorts attribute and adjust the port numbers as needed.
   • Press F1 and select the Remote-Containers: Rebuild Container command so the modifications are picked up.

Enabling HTTPS

To enable HTTPS for this sample, you can mount an exported copy of a locally generated dev certificate. Note that these instructions assume you already have the dotnet CLI installed on your local operating system.

1. Enable HTTPS in the sample by updating the env property in .vscode/launch.json as follows:

   "env": {
         "ASPNETCORE_ENVIRONMENT": "HttpsDevelopment"
   }

2. Next, export the SSL cert using the following command:

   Windows PowerShell

   dotnet dev-certs https --trust; dotnet dev-certs https -ep "$env:USERPROFILE/.aspnet/https/aspnetapp.pfx" -p "SecurePwdGoesHere"

   macOS/Linux terminal

   dotnet dev-certs https --trust; dotnet dev-certs https -ep "${HOME}/.aspnet/https/aspnetapp.pfx" -p "SecurePwdGoesHere"

3. Add the following in to .devcontainer/devcontainer.json:

   "remoteEnv": {
       "ASPNETCORE_Kestrel__Certificates__Default__Password": "SecurePwdGoesHere",
       "ASPNETCORE_Kestrel__Certificates__Default__Path": "/home/vscode/.aspnet/https/aspnetapp.pfx",
   }

4. Finally, make the certificate available in the container as follows:

   If using GitHub Codespaces and/or Remote - Containers

   1. Start the container/codespace
   2. Drag ~/.aspnet/https/aspnetapp.pfx from your local machine into the root of the File Explorer in VS Code.
   3. Open a terminal in VS Code and run:

      mkdir -p /home/vscode/.aspnet/https && mv aspnetapp.pfx /home/vscode/.aspnet/https

   If using only Remote - Containers with a local container

   Add the following to .devcontainer/devcontainer.json:

   "mounts": [ "source=${env:HOME}${env:USERPROFILE}/.aspnet/https,target=/home/vscode/.aspnet/https,type=bind" ]

5. If you've already opened your folder in a container, rebuild the container using the Remote-Containers: Rebuild Container command from the Command Palette (F1) so the settings take effect.

Next time you debug using VS Code (F5), you'll be able to use HTTPS! Note that you will need to specifically navigate to https://localhost:5001 to get the certificate to work (not https://127.0.0.1:5001).

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

License

Copyright © Microsoft Corporation All rights reserved.
Licensed under the MIT License. See LICENSE in the project root for license information.