Debug C++ application in Docker container with vscode

README.md

Debugging c++ project in docker container with vscode

You can attached a vscode session in a running docker container or vscode can create a docker container to attach.

For this configuration we are going to run a docker container in detached mode and then, connect to it using vscode in remote mode.

• Running container must have installed gdb
• Install Remote-containers extensions in your local vscode application

docker run --rm -d -p 12345:2225 -it \
           --name="docker-container" \
           --volume=/home/user/Downloads/project:/tmp/project \
           YOUR-DOCKER-IMAGE

vscode

1. Click on Remote explorer (left bar)
2. You will see the running docker container. For this example we will be using a docker image danieltobon43/pcl-docker:1.12.1-alpine3.15-dev-v4

3. Press on Attach or Open folder in container. See Documentation for more information.

vscode extensions

The following vscode extensions must be install in the vscode-remote version of the running container

• C/C++
• C/C++ Extension Pack
• CMake
• CMake Tools

Note

Remove any build folder you might have and then press the Debug button. This is because vscode CMake-Tools extension will create a build folder with debug symbols and if there is already a build/ folder you might find a permission error such as:

Error: EACCES: permission denied

Debugging

You can debug your application with a custom launch.json file or using CMake-Tools.

Debugging: launch.json

1. Create a launch.json file in the .vscode folder at the root of your project. example-json
2. Run and Debug (On the left panel) and choose CMakeDebugLaunch, play button

Debugging: CMake-tools

1. Click on the CMake-tools (On the left panel) and then, click right to show a new menu. Select debug

Enjoy

Now you can set a breakpoint in your remote-vscode session and start debugging your cpp application

Docker documentation

• Create a development container

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "CMakeDebugLaunch",
            "type": "cppdbg",
            "request": "launch",
            //"coreDumpPath": "GDB",
            // Resolved by CMake Tools:
            "program": "${command:cmake.launchTargetPath}",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}/build",
            "environment": [
                {
                    // add the directory where our target was built to the PATHs
                    // it gets resolved by CMake Tools:
                    "name": "PATH",
                    "value": "$PATH:${command:cmake.launchTargetDirectory}"
                },
                {
                    "name": "OTHER_VALUE",
                    "value": "Something something"
                }
            ],
            "externalConsole": false,
            "MIMode": "gdb",
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ]
        }
    ]
}