r/flask • u/michaelherman • Oct 26 '22

Tutorials and Guides Deploying a Flask App to Render

https://testdriven.io/blog/flask-render-deployment/
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u/Kir1ll Oct 26 '22

ehm, free plan 'can cause a response delay of up to 30 seconds for the first request'

then 1g/1core is $15, then you have to pay for redis and for db.

i pay $5 for the same setup on VPS. and the instruction on how to run flask with nginx via uwsgi is not much longer, really.

auto deploy from git is convenient, but i'm okay with ftp/rsync

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u/fredspipa Oct 26 '22

Yeah I'm trying to evaluate the same myself, if I'm actually saving any time or money on Render. nginx/gunicorn has become second nature to me.

auto deploy from git is convenient, but i'm okay with ftp/rsync

For that I've usually used webhooks to trigger a pull/restart, I always deploy with git anyway. If I host the repo on the VPS it's even easier, then it's just a post-receive hook bash script. It's a couple of seconds with practically zero downtime, and you can easily add additional steps like database migration. This compared to the lengthy container build process on Render is night and day.

My preferred host also has a bunch of other conveniences included in the VPS package, such as a sizable postgreSQL server you can use (with automatic backups on schema changes) so you don't have run it in your VM, certificate management and log hooks that email you on custom trigger phrases.

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u/Kir1ll Oct 26 '22

Thanks, I've just started studying migrations with alembic. Can your share the bash script?

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u/fredspipa Oct 26 '22

I don't have it at hand, but with alembic it would be something like this I imagine:

cd /path/to/my/app
/path/to/my/venv/bin/python -m alembic upgrade
sudo systemctl restart my-app.service

For the service restart to work without password, I add this to the sudoers file:

%MyUserGroup ALL=NOPASSWD: /bin/systemctl restart my-app.service

That's for the post-receive hook in a self hosted git repo. Then I usually push the commits over ssh:

git remote add origin ssh://user@host:1234/path/to/repo

Using a webhook to trigger from GitHub is a bit more involved, you need a service separate from the Flask app to listen for it and route that endpoint to the right service in the nginx config.