In this article, you will learn how to debug a container in Visual Studio Code running in Docker.

Prerequisites

The following prerequisites will be required to complete this tutorial:

• Visual Studio Code with the C# and Docker extension installed. If you don't have Visual Studio Code installed, download Visual Studio Code for free and install the C# extension and Docker extension before you begin.
• Windows Subsystem for Linux (WSL). If you don't have WSL installed, download Docker WSL for free before you begin.
• Docker Desktop. If you don't have Docker Desktop installed, download Docker Desktop for free before you begin.
• dotnet core web application or api with docker compose orchestration.

Add Visual Studio Code launch JSON file

1. Open a dotnet core web application or api in Visual Studio Code.

2. Select the Run and Debug tab, and then select create a launch.json file.

   

3. Enter D into the search box and then select Docker: Debug in Container.

   

4. Add the following JSON to the launch JSON file, replacing the following values.

   Parameter	Value
   name	Display name of your choice
   containerName	Your running container
   sourceFileMap (left path)	Path where the application code / dll is published in the docker container (this will be defined in your docker file)
   sourceFileMap (right path)	Path of the project in the Visual Studio Code workspace

   {
     "version": "0.2.0",
     "configurations": [
       {
         "name": "Monitored.API",
         "type": "docker",
         "request": "attach",
         "containerName": "monitoredapi",
         "platform": "netCore",
         "sourceFileMap": {
           "/src/Monitored.API": "${workspaceFolder}/Monitored.API"
         },
         "netCore": {
           "debuggerPath": "/remote_debugger/vsdbg"
         }
       }
     ]
   }
   

Configure docker compose and run a web application or api in a docker container

1. Add the following volume mapping to the service you would like to debug in the docker.compose.override yaml file.

   - ~/.vsdbg:/remote_debugger:rw
   

2. Select Terminal > New Terminal.

   

3. Run the following docker compose up command in the Terminal.

   docker compose -f docker-compose.yml -f docker-compose.override.yml up -d --build --force-recreate
   

   

Debug a web application or api in a container

1. Select the Run and Debug tab, and then choose the configuration you created in the Add visual studio code launch json file step above from the RUN AND DEBUG configuration list. Select the Start Debugging (play) icon.

   

2. Add a breakpoint to your application or api and then send a request that will hit the breakpoint.

   

Disconnect Debugger

1. Select the Disconnect plug icon to disconnect the debugger from the container.