Debug .NET Core within a container

Prerequisites

  1. Install the .NET Core SDK, which includes support for attaching to the .NET Core debugger.

  2. Install the Visual Studio Code C# extension, which includes support for attaching to the .NET Core debugger with VS Code.

  3. macOS users only: Add /usr/local/share/dotnet/sdk/NuGetFallbackFolder as a shared folder in your Docker preferences.

    dockerSharedFolders

Walkthrough

  1. If needed, create a .NET Core project with dotnet new.

  2. Open the project folder in VS Code.

  3. Wait until a notification appears asking if you want to add required assets for debugging. Select Yes:

    csharpPrompt

  4. Open the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)) and enter Docker: Add Docker Files to Workspace.... If you have already dockerized your app, you can instead do Docker: Initialize for Docker debugging. Follow the prompts.

  5. Switch to the Run view (⇧⌘D (Windows, Linux Ctrl+Shift+D)).

  6. Select the Docker .NET Core Launch launch configuration.

  7. Optionally, set a breakpoint.

  8. Start debugging! (F5)

Running and debugging with SSL support

To enable SSL (using the HTTPS protocol), you will need to make a few changes to your configuration.

  1. In the Dockerfile, add an EXPOSE line to the base section to define a separate port for HTTPS / SSL. Keep a separate EXPOSE line with a different port for HTTP requests.

    FROM mcr.microsoft.com/dotnet/aspnet:5.0 AS base
    WORKDIR /app
    EXPOSE 5000
    EXPOSE 5001
  2. In the .vscode/tasks.json file, add configureSsl: true to the netCore section. Also, add an environment variable ASPNETCORE_URLS in the dockerRun section of the docker-run: debug task, with the same port numbers you defined in the Dockerfile:

    dockerRun: {
        "env": {
           "ASPNETCORE_URLS": "https://+:5001;http://+:5000"
       }
     }
     netCore: {
         "appProject": "${workspacefolder}/MyProject.csproj",
         "enableDebugging": true,
         "configureSsl": true
     }

For additional customization options, see the documentation on Tasks and Debug containerized apps.