Packaging Python applications

The past, present and future solutions to this horrible problem.

Transcript

1. Packaging Python applications The past, present and future solutions to this horrible problem. Piotr Banaszkiewicz
2. Hi Piotr Banaszkiewicz @pbanaszkiewicz
3. The packaging problem Packaging Zipping Sharing Installing
4. The packaging problem Testing Building Zipping Testing your zip Sharing Installing
5. Packaging solutions Packaging solutions “Old” “Current” “New” eggs Buildout Fabric (*) virtualenv Global (site-packages) Vagrant System packages (DEBs, RPMs, etc) wheels LXC (Docker)
6. Old solutions
8. Python eggs ✔ Python importables ✔ Handle Python binary package ✗ Don't solve project dependencies ✗ Tied to Python version – need to be built for target systems (include .pyc files) ✗ Not a standard + old age, bad naming convention
9. Python eggs Conclusion: unless you're force to use eggs, use something newer and cleverer.
10. Buildout ✔ Dependency and configuration management ✗ Requires lots of configuration itself ✗ Sort of steep learning curve
11. Buildout Conclusion: meh.
12. Fabric • Used as a package solution :O ✗ …but it's not intended to. Conclusion: please don't.
13. Python global site-packages • Making your project a Python package is good. • Installing your project system wide may be wrong.
14. Current solutions
15. Virtualenv • Isolates your Python interpreter and packages • Standard in Python world
16. Virtualenv Conclusion: YES YES YES.
17. Thank you for using virtualenv!
18. Vagrant • Automatization + virtualization = Vagrant • Big companies use it to speed setting up development, to save resources • Take a look at my last year's PyCon PL presentation “A Thing About Vagrant” https://speakerdeck.com/pbanaszkiewicz/
19. Vagrant ✔ Portable development environments ✔ You have everything under control ✗ VMs are heavy ✗ ...and sometimes wonky Conclusion: it's awesome.
20. System packages • .debs, .rpms • Think: virtualenv with your whole project installed from Linux package
21. System packages • Good idea, but virtualenvs are not relocatable
22. System packages • It's hard to package virtualenvs into RPM. • Too much effort for too little gain. • Alex Hudson, Packaging a virtualenv: really not relocatable http://www.alexhudson.com/2013/05/24/packaging-a -virtualenv-really-not-relocatable/
23. System packages • Impossible to create generic DEB or RPM with virtualenv in it • But if you control target host... Then it's feasible
24. System packages: fpm • fpm – to create DEBs and RPMs quickly • Does not follow Debian policy nor RPM packaging guidelines • But supposedly works • Listen to Hynek Schlawack's talks or read his blog posts: hynek.me, “Python Application Deployment with Native Packages”
25. System packages: dh-virtualenv • Fresh: about one and half week old • By Spotify • Builds “correct” DEBs with necessary dependencies from requirements file and with virtualenv inside • Has some limitations (like installation path) • https://github.com/spotify/dh-virtualenv
26. “New” solutions
27. Python on wheels.
28. Wheels • Package format for Python (for binary packages too!) • Package names: package-version-pythonversion-abi-platform.whl • Supports signed packages! • It's quick
29. Wheels: a working :) example • Generating wheels for a project • Installing wheels
30. Wheels Conclusion: YES YES YES.
31. LXC and Docker • Containers: think about smaller, lighter virtual machines with no CPU or memory overhead • Buzz around Docker
32. Docker ✔ Great idea ✔ Containers are smoother than virtual machines ✗ Concerns about AUFS file system ✗ Apparently software is full of bugs ✗ So are linux containers
33. Docker as a packaging solution • Build LXC with everything included • (Simply put shell commands in Dockerfile) • Would be round 100MB (?), compared to smallest Vagrant boxes weighting 300-400MB
34. Docker Conclusion: yeah, it's great, but young and you should watch out for bugs.
35. Thank you for listening • Snake with eggs: “Ball Python with eggs”, http://www.lihs.org/files/photos4.htm • Thankful kitten: google for “Cute Cat” • Sad pug: reise.bt.no • Python on wheels: “Snakes Need Wheels - Snake Push Toy” on Flickr • Any questions? Piotr Banaszkiewicz @pbanaszkiewicz
36. Bonus: PEP 453 • Pip will be included within Python 3.4 • And will be a default package manager for Python