Debugging

Server debugging

To run a debug server in VS Code, add the following file .vscode/launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "xlwings-server",
            "type": "debugpy",
            "request": "launch",
            "module": "xlwings_server.cli",
            "args": [],
            "console": "integratedTerminal",
            "justMyCode": false,
            "python": "${workspaceFolder}/.venv/bin/python",
            "env": {
                "PYTHONPATH": "${workspaceFolder}"
            },
            "cwd": "${workspaceFolder}"
        }
    ]
}

This allows you to start the debugger by pressing F5.

Office.js add-in debugging

If you need to debug errors with Office.js add-ins, you need to open the developer tools of the browser engine that’s being used. Depending on the platform, the process is different:

  • Desktop Excel on Windows: to open the DevTools, right-click on the task pane and select Inspect.

  • Desktop Excel on macOS: to open Web Inspector, you’ll need to run the following command in a Terminal once:

    defaults write com.microsoft.Excel OfficeWebAddinDeveloperExtras -bool true

    Then, after restarting Excel, right-click on the task pane and select Inspect Element.

    Note

    After running this command, you might see an empty browser window when using other add-ins. To get rid of this, you would need to disable debugging again by running the same command in the Terminal with false instead of true.

  • Excel on the web: open the developer tools of the browser you’re using. For example, in Chrome you can type F12.

Once you have the developer tools showing up, you usually want to look at the following tabs:

  • Console: Here, you’ll find any errors printed. If you use Excel on the web, you’ll see a lot of error messages and warnings that are unrelated to the add-in though, so you’ll need to watch out for relevant messages within the noise.

  • Network: Here, you’ll see if the browser has an issue with loading a specific file. You’ll also be able to double-check the URL of the server and you are able to click on a file to see the content and its headers. Note, however, that you will need to have the Network tab open before making any requests (i.e., reload the add-in, click a button, or run a custom function).