How to Upgrade to the Newest Shiniest Django Version

How to upgrade to the newest shiniest Django

version

DjangoCon Europe Susan tan

Cisco in san francisco, CA

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Hello! I’m Susan• I’m a software engineer at Cisco in San Francisco,

CA.

• Previously worked at a cloud startup Piston.

• Works with python apis, web development, works on Cisco’s openstack horizon Django project

• Worked on open source Django project www.openhatch.org

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Quick Audience Survey

How many people currently work on at least one project with Django

• below 1.6?

• 1.7?

• 1.8?

• 1.9?

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Why should you do an upgrade?

• get new features, bug fixes, security fixes

• easier to upgrade to the next version in future

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A.B.C

backwards-incompatible

new features backwards compatible

backwards-compatible bug fixes.

Semantic versioning review

major minor patch

Read http://semver.org/5

Django does NOT follow semantic versioning FYI

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• Major release number is an extension of minor release number.

• From semantic versioning, Django 1.7 should be 2.0, because backwards-incompatible.

When is right time to upgrade?

• Your project’s Django version is no longer supported.

• Do a patch upgrade! Always.

• You have an existing comprehensive test suite. • If you don’t have a test suite, then now would be a

good time to start writing unit tests.

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Current Django Versions

Source: https://www.djangoproject.com/download/

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Future Roadmap

Source: https://www.djangoproject.com/download/

[3] Last version to support Python 2.7.

• Hard to know how much time or effort it takes

• Hard to know which tests will break or even run

• Hard to know if UI will continue working

• Confirm functionality at every part of development

• ie: local host, staging, deployment.

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Why is upgrading a Django project a difficult thing to do?

What does the end product look like in code?

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Upgrading OpenHatch

Upgrading OpenHatch

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• OpenHatch vendors all its dependencies. • Commits that are "Add upgraded version of

library Z” with full library source code.

• ~4 weeks to go from broken Django project to functional upgraded Django project, including dependency updates.

• Doing frequent git rebasing & resolving merge conflicts is terrible.

What is step zero?

pip uninstall django

pip install django==<NUMBER>

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What NOT to doDo not skip over versions. If you do, you will

• miss deprecation warnings • supported for 2 versions

• have invalid code • call APIs or use modules that don’t

exist in newer Django version

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What is step 1?

python manage.py tests Possible results: 1. Your tests may not even run. 2. Your tests may fail. 3. All your tests pass.

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Option 3: All your tests pass right after installing new Django

Option 2: Your tests fail. What’s next if tests fail?

Fix tests, one at a time

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At the end, what does “SUCCESS” look like for a fully upgraded project?

In this order: 1. All tests pass with no errors or deprecation

warnings. 2. UI works locally. 3. Deployment works on staging. 4. UI works on staging. 5. Deployment works on production. 6. UI works on production.

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Break a big task into smaller tasks.

What is this entire process?Run thru these steps in this order:

1. Run existing unit tests. Fix broken tests. 2. Run same existing unit tests. Confirm that

fewer tests fail. 3. Rinse and repeat steps 1-2 continuously

until all tests pass. 4. Check the UI to see if it all still works. 5. Edit deploy script, requirements.txt,

documentation.22

What are the challenges?

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> ls vendor/packages/ BeautifulSoup django-authopenid docutils odict south Django django-celery feedparser ordereddict sphinx Jinja2 django-debug-toolbar gdata python-dateutil sqlparse PyJWT django-extensions ghettoq python-memcached staticgenerator PyYaml django-http-proxy html2text python-mimeparse twill Pygments django-inplaceedit html5lib python-openid twisted amqp django-invitation importlib python-otp typecheck anyjson django-kombu irc python-patch unicodecsv beautifulsoup4 django-model-utils jsmin python-social-auth unittest-xml-reporting bleach django-picklefield kombu pytz webob celery django-registration markupsafe

Lots of dependencies may break

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Options: 1. Upgrade dependency. 2. Patch it yourself (and upstream it). 3. Use a different similar dependency.

LOTS of release notes

• Deprecation warnings or test errors will tell you which release notes to read.

• Replace syntax with newer syntax.

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Some are simple changesUpgrade to 1.5: Fix deprecation issue with AdminMediaHandler

Edit manage.py when upgrading to Django 1.5

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Some are simple changes

Replace "direct_to_template()" with generic template view. This is a deprecation documented in Django 1.5 release notes.

LOTS of repetition

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Fix the template quotes syntax issue

This syntax issue is documented in release notes when upgrading to Django 1.5. In templates, change tags like {% url myview %} to {% url "myview" %}

Take aways

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• Do an upgrade 1 version at a time. • Run unit tests, see what breaks, then fix tests

1 at a time. • Read release notes. • Break every task into small steps.

• A checklist helps. • So does taking notes.

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How many people have been planning to do an

upgrade on their Django project?

Announcing Django Upgrade Open Space

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Have you done Django upgrades before or are looking to do so for your personal project(s)?

WHO: Anyone who wants to upgrade their projects. Anyone with experience with upgrading projects. WHAT: Work on your Django project. Mentor(s) will be there. WHEN: this Saturday & Sunday mornings

Thanks! Hope this helps.

Thanks Cisco for sponsoring me to go on this trip.

Susan Twitter: @ArcTanSusan

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