Full Web Apps with FastAPI Transcripts
Chapter: Creating our first FastAPI *site*
Lecture: Ready for running in production
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Now, before we call our little basic structure here finished. I do want to show you one quick little thing. Notice I was able to go over here,
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right click and say run. And I can also press this button and everything looks golden. But the way that we actually run FastAPI in production is not to
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go and say Python run this file. What we're gonna do is we're gonna say set up Gunicorn, which is going to oversee a farm of Uvicorn worker processes,
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and each one of those is going to run this application. And that way, if something goes wrong with one, it can be restarted. You can do scale out.
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There's all sorts of cool advantages to that. And that's generally how Python web apps run in production anyway. And when we do it in that mode,
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the way we're gonna have basically implicitly behind the scenes do that chain. I talked about
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what's gonna happen is, we're going to say uvicorn main thing here. What is it that we're working with? And then what is the name of this thing here,
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which is app in our example. So we're gonna go to the main module and find the app instance and run it.
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Watch what happens if I try to run it here. It says whoa, whoa. You're somehow like double running it. I'm not really sure what's going on here.
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And that's because this is really just for testing, and we need a different way to run it in production.
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So we're just gonna quickly fix that and say:only if you try to run it here in dev, do we want to do that.
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So notice this, a live template is gonna expand out to if the name is main.
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This is the Python convention. Say this file is being run directly rather than imported and else I don't know.
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This is what we're gonna end up doing in production. There's actually some things will ultimately need to do here.
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But for now, there's just nothing else happening. If I run over here through this mode, you can see it's running fine.
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And if I go into the terminal now and I try to run it like this hey, look, it runs fine as well.
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Okay, so you'll see that as we get this little bit more complicated. Think more things going on, like setting up the database at start up and so
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on. There's gonna be some interesting balancing act that we have to do around this
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but I wanted to make sure that you I focused on this specifically because it's easy to just say uvicorn run,
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but then seems like it works and then it doesn't work in production. And that's why, right, this is fine when we press the run button
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but in production were running through a completely different chain of events that uses uvicorn module:variable_name.
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So I want to make sure we get this set up right from the start.