mirror of https://github.com/tiangolo/fastapi.git
116 lines
2.4 KiB
Markdown
116 lines
2.4 KiB
Markdown
# Debugging
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You can connect the debugger in your editor, for example with Visual Studio Code or PyCharm.
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## Call `uvicorn`
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In your FastAPI application, import and run `uvicorn` directly:
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```Python hl_lines="1 15"
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{!../../docs_src/debugging/tutorial001.py!}
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```
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### About `__name__ == "__main__"`
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The main purpose of the `__name__ == "__main__"` is to have some code that is executed when your file is called with:
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<div class="termy">
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```console
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$ python myapp.py
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```
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</div>
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but is not called when another file imports it, like in:
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```Python
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from myapp import app
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```
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#### More details
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Let's say your file is named `myapp.py`.
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If you run it with:
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<div class="termy">
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```console
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$ python myapp.py
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```
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</div>
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then the internal variable `__name__` in your file, created automatically by Python, will have as value the string `"__main__"`.
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So, the section:
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```Python
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uvicorn.run(app, host="0.0.0.0", port=8000)
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```
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will run.
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---
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This won't happen if you import that module (file).
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So, if you have another file `importer.py` with:
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```Python
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from myapp import app
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# Some more code
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```
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in that case, the automatically created variable inside of `myapp.py` will not have the variable `__name__` with a value of `"__main__"`.
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So, the line:
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```Python
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uvicorn.run(app, host="0.0.0.0", port=8000)
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```
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will not be executed.
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/// info
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For more information, check <a href="https://docs.python.org/3/library/__main__.html" class="external-link" target="_blank">the official Python docs</a>.
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///
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## Run your code with your debugger
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Because you are running the Uvicorn server directly from your code, you can call your Python program (your FastAPI application) directly from the debugger.
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---
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For example, in Visual Studio Code, you can:
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* Go to the "Debug" panel.
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* "Add configuration...".
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* Select "Python"
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* Run the debugger with the option "`Python: Current File (Integrated Terminal)`".
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It will then start the server with your **FastAPI** code, stop at your breakpoints, etc.
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Here's how it might look:
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<img src="/img/tutorial/debugging/image01.png">
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---
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If you use Pycharm, you can:
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* Open the "Run" menu.
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* Select the option "Debug...".
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* Then a context menu shows up.
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* Select the file to debug (in this case, `main.py`).
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It will then start the server with your **FastAPI** code, stop at your breakpoints, etc.
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Here's how it might look:
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<img src="/img/tutorial/debugging/image02.png">
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