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Django 1.8 to 1.11: Tips for an (almost) painless upgrade

Ali Tycast

July 17, 2019

The Black Tux + PyLadies + LA Django

Hello!

I’m Ali -

• Back End Developer
• Python, Ruby
• Business Operations team at The Black Tux

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Why did we upgrade from Django 1.8 to 1.11?

We want to be on a supported version

We were missing out on:

• Security updates
• Bug fixes

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• Current version is 2.2.3
• 1.11 is the latest release on Python 2.7

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Make it a point to do something everyday that you don't want to do.

• Mark Twain

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How’d we do it?

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Read the release notes

• Deprecated features
• Backwards incompatibility
• Database changes

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Example:

In model forms, CharField with null=True now saves NULL for blank values instead of empty strings.

Upgrade dependencies

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• django-debug-toolbar==1.8
• django-nose==1.4.6
• django-object-actions==1.0.0
• sorl-thumbnail==12.5.0
• django-concurrency==1.4
• django-cors-headers==2.4.1
• django-extensions==1.9.9
• django-lionheart-helpers==3.0.4
• django-localflavor==1.6
• django-redis==4.8.0
• six==1.12.0
• djangorestframework==3.6.4

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Update our imports

• All models need to be defined inside an installed application.

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• Not possible to import them before their application is loaded.

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• Not possible to import models inside the root package of an application.

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Update our imports

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Fix deprecation warnings

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Fix deprecation warnings

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A lot of other random fixes...

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How’d we release this?

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You may have to fight a battle more than once to win it.

• Margaret Thatcher

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Multiple releases

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• Package upgrades

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• Import changes

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• Runtime warnings (timezones)

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• Everything else

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Now we can talk about problems...

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😭

Static assets

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• We committed Django admin static files to our repo years ago
• Django admin files conflicted with what we had committed when we upgraded to 1.11

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• We didn’t realize django admin magic was generating static assets, so we had removed release steps to upload these 1.11 assets to S3

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• Staging and prod used different packages to upload our static assets to S3, which made issues difficult to debug

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What did we learn?

Don’t avoid upgrading!

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• You need to do it. Just do it.

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• Updating code is harder the longer the version distance is

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• Upgrading as each new Django release is available makes future upgrades less painful by keeping your code base up to date.

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Know your app

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• Django uses a lot of “magic” - make sure you know when you’re using it, how you're using it, and why

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• If you know the “when, how and why”, you can catch breaking changes before they happen

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Follow convention… or don’t

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• It’s okay to deviate from convention..

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• But do it for a reason. And document it.

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Tests

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• Write tests!

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• Even ones you don’t think you need!
• Django admin

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• Run tests!

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Keep your environments in sync

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• Differences between environments (i.e.dev, staging, production) don't seem like a big deal... until they are

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• The fact that we used different Static Asset backends on staging and prod really hurt us

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• We also had bugs in our dev and staging environments that didn’t exist on prod… ouch.

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Pay attention to warnings

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• Deprecation warnings (or any warnings) are there for a reason

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• Keep up with them and save yourself a lot of time… future you will be very happy!

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Lean on your team

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• It helps everyone to ask for help.

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• The more people involved, the more people who will learn and have a deeper understanding of your new version!

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Commit

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• This is a real project, treat it as such

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• Timelines

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• Deadlines

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• This is how you get the support of your team!

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Questions?

Thank you!

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