1. and what the developer saw there
Through the yum API,
and what the developer saw there
Paul Nasrat
Software Engineer - Red Hat, Inc.

2. Summary
Main text
Introduction
yum-utils
yum shell
yum plugins
yum API

3. Introduction RPM Basic network awareness and dependency solving Yup
YellowDog updater
Duke University heavy use
Yum
Needs of Duke (particularly physics)
Seth Vidal - YellowDog updater modified
Recent yum development
Larger team of contributors
RPM metadata, urlgrabber, sqlite caching
Hooks for third parties (shell, plugins, API)

4. Extending yum Why? Tool automation Build automation Quality Assurance
Who?
System Administrators
Packagers
OS Developers
How?
Python
Yum 2.3.x +

5. Yum-utils - repoquery
Replaces rpm -q and rpmdb-fedora for metadata repositories
repoquery --requires demo-requirer
repoquery –-provides demo-provider
repoquery –-whatprovides
RPM style queryformat
repoquery –queryformat ‘%{name}.%{arch}’ demo

6. Yum utils yumdownloader Download packages Resolve dependencies
Supports source rpm retrieval
yum-builddep
Install build dependencies for a package

7. yum shell Simple cli interface for advanced users
Not a scripting language – no logic control, error handling
yum shell
> help
commands: clean, config, exit, groupinfo, groupinstall, grouplist,
groupremove, groupupdate, info, install, list,
localinstall, makecache, provides, quit, remove,
repo, run, search, transaction, update
> repo disable *
> repo enable yum-demo
> install yum-shell-demo
> transaction solve
> transaction run

8. RPM core concepts Header object Tags and values
Python dictionary like.
Transaction based
“Workhorse of RPM”
Transaction set
Flags – A transaction set can be modified or setup with various flags
Test only

9. yum plugins Hook and slot based extensibility Configuration
Command line option addition
Pre/post repository setup
Pre/post download
Pre/post
Versioned API that plugins require
Conduit for access to transaction information

10. yum plugin - example
# tsflags by Panu Matilainen
requires_api_version = '2.1'
def init_hook(conduit):
parser = conduit.getOptParser()
parser.add_option('--tsflags', dest='tsflags')
def postreposetup_hook(conduit):
opts, args = conduit.getCmdLine()
conf = conduit.getConf()
if opts.tsflags:
flags = opts.tsflags.split(',')
conf.setConfigOption('tsflags', flags)

11. Yum api Why? Alternative front ends Plugins insufficient
Stand alone applications
How?
rpmUtils module – rpm-python wrapper
yum module - YumBase
What?
yum-utils
Fedora Core 5 - anacoda
pup

12. Yum API
YumBase
This is a primary structure and base class. It houses the objects and methods needed to perform most things in yum. It is almost an abstract class in that you will need to add your own class above it for most real use.
Handles configuration setup
Repository setup
Dummy log routines
Callbacks
RPM Callbacks
urlgrabber progress bar

13. Future plans Yum everywhere in Fedora Anaconda Pup
System-config-packages replacement
Applet replacement
Provide a stack of components for graphical yum front ends
Speaking with yumex developers
Speed and memory footprint improvements

14. Further information
yum-devel list
RPM metadata list

15. Thanks and questions... Seth Vidal – primary developer Jeremy Katz
Adrian Likins
Matthew Miller
Michael Stenner
Icon Riabitsev
Ryan Tomayko
Robert G. Brown
Hollis Blanchard
Grigory Bakunov
Menno Smits
Gijs Hollestelle
Terje Rosten