Python builder for WSGI applications on Vercel
npm install @ardnt/vercel-python-wsgi


If you have an existing WSGI app, getting this builder to work for you is a
piece of 🍰!
Add a vercel.json file to the root of your application:
``json`
{
"builds": [{
"src": "index.py",
"use": "@ardnt/vercel-python-wsgi",
"config": { "maxLambdaSize": "15mb" }
}]
}
This configuration is doing a few things in the "builds" part:
1. "src": "index.py"index.py
This tells Now that there is one entrypoint to build for. is a"use": "@ardnt/vercel-python-wsgi"
file we'll create shortly.
2. "config": { "maxLambdaSize": "15mb" }
Tell Now to use this builder when deploying your application
3.
Bump up the maximum size of the built application to accommodate some larger
python WSGI libraries (like Django or Flask). This may not be necessary for
you.
Add index.py to the root of your application. This entrypoint should makeapplication
available an object named that is an instance of your WSGI
application. E.g.:
`pythondjango_appFor a Dango app
from django_app.wsgi import applicationReplace
with the appropriate name to point towards your project's`wsgi.py file
Look at your framework documentation for help getting access to the WSGI
application.
If the WSGI instance isn't named application you can set thewsgiApplicationName configuration option to match your application's name (see
the configuration section below).
That's it, you're ready to go:
``
$ vercel
> Deploying python-wsgi-app
...
> Success! Deployment ready [57s]
Your project may optionally include a requirements.txt file to declare any
dependencies, e.g.:
``requirements.txt
Django >=2.2,<2.3
Be aware that the builder will install Werkzeug as a requirement of theWerkzeug
handler. This can cause issues if your project requires a different version of than the handler.
Select the lambda runtime. Defaults to python3.6.`json`
{
"builds": [{
"config": { "runtime": "python3.6" }
}]
}
Select the WSGI application to run from your entrypoint. Defaults to
application.`json`
{
"builds": [{
"config": { "wsgiApplicationName": "application" }
}]
}
You'll likely want all requests arriving at your deployment url to be routed to
your application. You can do this by adding a route rewrite to the Now
configuration:
`json`
{
"builds": [{
"src": "index.py",
"use": "@ardnt/vercel-python-wsgi"
}],
"routes" : [{
"src" : "/(.*)", "dest":"/"
}]
}
If having an extra file in your project is troublesome or seems unecessary, it's
also possible to configure Now to use your application directly, without passing
it through index.py.
If your WSGI application lives in vercel_app/wsgi.py and is named application,`
then you can configure it as the entrypoint and adjust routes accordingly:json``
{
"builds": [{
"src": "vercel_app/wsgi.py",
"use": "@ardnt/vercel-python-wsgi"
}],
"routes" : [{
"src" : "/(.*)", "dest":"/vercel_app/wsgi.py"
}]
}
At the time of writing, Vercel runs on AWS Lambda. This has a number of
implications on what libaries will be available to you, notably:
- PostgreSQL, so psycopg2 won't work out of the box
- MySQL, so MySQL adapters won't work out of the box either
- Sqlite, so the built-in Sqlite adapter won't be available
- [ ] Add tests for various types of requests
This implementation draws upon work from:
- @clement on
now-builders/#163
- serverless and
serverless-wsgi
- @sisp on
now-builders/#95
- Zappa by
@miserlou