Django running on Zeit Now

Tutorial

Install Django

$ mkdir now-django-example
$ cd now-django-example
$ pip install Django
$ django-admin startproject now_app .

Add an app

$ python manage.py startapp example

Add the new app to your application settings (now_app/settings.py):

# settings.py
INSTALLED_APPS = [
    # ...
    'example',
]

Be sure to also include your new app URLs in your project URLs file (now_app/urls.py):

# now_app/urls.py
from django.urls import path, include

urlpatterns = [
    ...
    path('', include('example.urls')),
]

Create the first view

Add the code below (a simple view that returns the current time) to example/views.py:

# example/views.py
from datetime import datetime

from django.http import HttpResponse


def index(request):
    now = datetime.now()
    html = f'''
    <html>
        <body>
            <h1>Hello from Zeit Now!</h1>
            <p>The current time is { now }.</p>
        </body>
    </html>
    '''
    return HttpResponse(html)

Add the first URL

Add the code below to a new file example/urls.py:

# example/urls.py
from django.urls import path

from example.views import index


urlpatterns = [
    path('', index),
]

Test your progress

Start a test server and navigate to localhost:8000, you should see the index view you just created:

$ python manage.py runserver

Get ready for Now

Add the Now configuration file

Create a new file index.py to act as your application entrypoint for Now. The file should import the WSGI application you want to use and make it available as application:

# index.py
from now_app.wsgi import application

Create a new file now.json and add the code below to it:

{
    "version": 2,
    "name": "python-wsgi-example",
    "builds": [{
        "src": "index.py",
        "use": "@ardent-labs/now-python-wsgi",
        "config": { "maxLambdaSize": "15mb" }
    }]
}

This configuration sets up a few things:

"src": "index.py" tells Now that index.py is the only application entrypoint to build
"use": "@ardent-labs/now-python-wsgi" tells Now to use the now-python-wsgi builder (you can read more about the builder at https://github.com/ardent-co/now-python-wsgi)
"config": { "maxLambdaSize": "15mb" } ups the limit on the size of the code blob passed to lambda (Django is pretty beefy)

Add django to requirements.txt

# requirements.txt
django==2.1.7

Update your Django settings

First, update allowed hosts in settings.py to include now.sh:

# settings.py
ALLOWED_HOSTS = ['.now.sh']

Second, get rid of your database configuration since many of the libraries django may attempt to load are not available on lambda (and will create an error when python can't find the missing module):

# settings.py
DATABASES = {}

Deploy

With now installed you can deploy your new application:

$ now
> Deploying now-django-example under jayhale
...
> Success! Deployment ready [57s]

Check your results by visiting https://zeit.co/dashboard/project/now-django-example

Ready to add a database? Try Postgres.

Configure Django Settings

Configure now_app/settings.py to accept database connection strings using dj_database_url

# now_app/settings.py

import dj_database_url

DATABASES = {'default': dj_database_url.config(conn_max_age=600)}

While in now_app/settings.py, add whitenoise. WhiteNoiseMiddleware enables Django to serve its own static files. Without whitenoise, Django Admin won't import necessary CSS, and we will use the Django admin to test whether or not our database connection is working.

# now_app/settings.py

MIDDLEWARE = [
    ... other stuff ...,
    'whitenoise.middleware.WhiteNoiseMiddleware',
]

Add both whitenoise and dj_database_url to requirements.txt

At this point, requirements.txt file should include:

# requirements.txt

dj-database-url==0.5.0
Django==2.1.7
Werkzeug >=0.14,<1
whitenoise

Add a pre-compiled Django Postgres adapter: psycopg2

Django needs an adapter like psycopg2 to connect to Postgres.

Only certain libraries are available in the lambda environment, and psycopg2 is not one of them... so simply adding psycopg2 to requirements.txt will not work.

Instead, bundle a pre-compiled psycopg2 with your project at root level, where Django can import as needed. psycopg2 must be compiled for the correct python version and environment.

Fortunately, @jkehler has done the work for us in this repo: https://github.com/jkehler/awslambda-psycopg2

Download package awslambda-psychopg2 as a zip file, and copy this subfolder into your project's root directory:

awslambda-psychopg2-master/with_ssl_support/psychopg2-3.6

Rename folder psychopg2-3.6 to psychopg2

Project directory should look like this:

/now-django-example
    /example
    /now_app
    /psycopg2 # this one you just added.
    index.py
    manage.py
    now.json
    README.md
    requirements.txt

Create a database server

One easy way to get up and running fast is to use a Digital Ocean Database Cluster.

Log in at digitalocean.com
Select the green 'Create' button in the top right > Databases
Follow instructions to create a PostgreSQL 10 server

Feel free to skip the "getting started" section.

On the Connection Details panel, select dropdown "Connection String" and Copy.

Your connection string should look something like this:

postgres://doadmin:<YOUR-PASSWORD>@<YOUR-DATABASE-SERVER>.db.ondigitalocean.com:25060/defaultdb?sslmode=require

Definitely don't use this default connection string in prod. For prod, create database users with specific permissions. We only use this connection string because it is easy for a tutorial / proof-of-concept.

Seed the database server with a user

Lambda environments are immutable, and you cannot run environment commands like python manage.py ...

One way to seed the database is to run Django commands locally, before deploying to Now (though connecting to the same database server).

In your environment, set environment variable DATABASE_URL to the database connection string from Digital Ocean.

user:~/now-django-example $ export DATABASE_URL=postgres://doadmin:<YOUR-PASSWORD>@<YOUR-DATABASE-SERVER>.db.ondigitalocean.com:25060/defaultdb?sslmode=require

user:~/now-django-example $ echo $DATABASE_URL
postgres://doadmin:<YOUR-PASSWORD>@<YOUR-DATABASE-SERVER>.db.ondigitalocean.com:25060/defaultdb?sslmode=require

Ensure your local environment has installed requirements.txt

user:~/now-django-example $ python3 -m pip install -r requirements.txt

Then use manage.py to create a superuser:

user:~/now-django-example $ python3 manage.py createsuperuser

Follow Django's instructions to create the super user.

Run the server and try logging in to make sure the database is seeded correctly.

user:~/now-django-example $ python3 manage.py runserver

Navigate to: https://localhost:8000/admin and log in using the super user you created above.

Your database is seeded. Stop the server using CTRL+C and proceed with Now deployment.

Modify now.json environment variables and routes.

dj_database_url will look for an environment variable named DATABASE_URL.

Your DATABASE_URL, however, contains sensitive information, so we will use a now secret.

user:~/now-django-example $ now secret add db-url postgres://doadmin:<YOUR-PASSWORD>@<YOUR-DATABASE-SERVER>.db.ondigitalocean.com:25060/defaultdb?sslmode=require
> Success! Secret db-url added (pejowei) [466ms]

Add environment variable to now.json

{
    "env":{
        "DATABASE_URL":"@db-url"
    }
}

While editing now.json, this is a good time to update routes.

We want all requests and responses to be routed through the index.py handler file, so your Django application needs to be routed like a single-page app.

Add the following to now.json to send all requests to your Django wsgi application via index.py:

{
    "routes" : [{
        "src" : "/(.*)", "dest":"/"
    }],
}

Deploy

You can now redeploy (pun intended) your new application:

$ now
> Deploying now-django-example under pejowei
...
> Success! Deployment ready [57s]

Check your results by visiting https://zeit.co/dashboard/project/now-django-example

You will know if everything worked if you can log into Django admin and add a user.

Django admin will be available at https://YOUR-DEPLOYMENT.now.sh/admin

Good luck!

pejowei / now-django-example Goto Github PK

now-django-example's Introduction

Django running on Zeit Now

Tutorial

Install Django

Add an app

Create the first view

Add the first URL

Test your progress

Get ready for Now

Add the Now configuration file

Update your Django settings

Deploy

Ready to add a database? Try Postgres.

Configure Django Settings

Add a pre-compiled Django Postgres adapter: psycopg2

Create a database server

Seed the database server with a user

Modify now.json environment variables and routes.

Deploy

now-django-example's People

Contributors

Watchers

Recommend Projects

Recommend Topics

Recommend Org