Debug with VSCode

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how to debug in vscode

Debugging in Visual Studio Code (VSCode) is a powerful feature that helps you find and fix issues in your code. Here's a step-by-step guide to get you started:

1. Install Required Extensions

Ensure you have the necessary extensions installed for the language you're working with. For example:

• Python: Python extension

• JavaScript/TypeScript: JavaScript Debugger (built-in)

• C++: C++ extension

2. Open Your Project

Open the folder containing your project in VSCode.

3. Configure Debugging

VSCode uses a launch.json file to configure the debugger for your project.

1. Open the Debug view by clicking the debug icon in the Activity Bar on the side of the VSCode window.

2. Click on the gear icon to configure the launch.json file.

3. Select the appropriate environment (e.g., Python, Node.js) if prompted.

A launch.json file will be created in the .vscode directory. It looks something like this for a Python project:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Python: Current File",
      "type": "python",
      "request": "launch",
      "program": "${file}",
      "console": "integratedTerminal"
    }
  ]
}

4. Set Breakpoints

Click in the gutter (the area to the left of the line numbers) to set breakpoints in your code. A red dot will appear, indicating the

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how to debug fastapi in python

Debugging a FastAPI application in Visual Studio Code (VSCode) is straightforward with the right setup. Here’s how you can do it:

1. Install Required Extensions

Ensure you have the following extensions installed in VSCode:

• Python extension

2. Install Dependencies

Make sure you have uvicorn installed as it's the ASGI server commonly used with FastAPI.

pip install fastapi uvicorn

3. Open Your FastAPI Project

Open the folder containing your FastAPI project in VSCode.

4. Create a launch.json Configuration

VSCode uses a launch.json file to configure the debugger. Follow these steps to create it:

1. Open the Debug view by clicking the debug icon in the Activity Bar on the side of the VSCode window.

2. Click on the gear icon to create a launch.json file.

3. Select "Python" as the environment.

Add the following configuration to the launch.json file:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Python: FastAPI",
      "type": "python",
      "request": "launch",
      "module": "uvicorn",
      "args": [
        "main:app",  // Replace with your app entry point
        "--host",
        "127.0.0.1",
        "--port",
        "8000",
        "--reload"
      ],
      "jinja": true
    }
  ]
}

Replace main:app with the appropriate module and app instance name for your FastAPI project. For example, if your main file is app.py and your FastAPI instance is named app, you should use app:app.

5. Set Breakpoints

Set breakpoints in your FastAPI code where you want the debugger to pause. You can do this by clicking in the gutter next to the line numbers in your code.

6. Start Debugging

1. Open the Debug view by clicking the debug icon in the Activity Bar.

2. Select the "Python: FastAPI" configuration.

3. Click the green play button to start debugging.

VSCode will start your FastAPI application using uvicorn, and you will be able to hit the breakpoints you set.

7. Access Your Application

Open your web browser and navigate to http://127.0.0.1:8000. Your FastAPI application should be running, and you can test the endpoints you have created.

Example FastAPI Application (main.py)

Here’s a simple FastAPI application for reference:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"Hello": "World"}

@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
    return {"item_id": item_id, "q": q}

Now, when you navigate to http://127.0.0.1:8000/items/1?q=test in your browser, the debugger in VSCode should hit any breakpoints you have set in your FastAPI code.

This setup allows you to effectively debug your FastAPI application using VSCode, providing you with a robust environment to diagnose and fix issues in your code.

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