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• Configuration management is the management of system change to software products– Version management: consistent scheme of version
identification– System building (assembling components into a
system)– Change management: configuration data base records
information about changes and change requests• System releases include executable code, data,
configuration files and documentation• CASE tools are available to support all CM
activities (stand-alone and integrated systems)
Configuration Management
CASE Tools for Configuration Management
• Versioning – RCS (Revision Control System)– CVS (Concurrent Version Control)– Subversion
• Build– Shell scripts, make, ant
• Change Management– Bug database, change tracking
• Release Management– Feature tracking, rpm (build packages)
• Configuration management = Version + Change + Build +Release– Rational ClearCase– SourceForge
Version Control• Discipline of managing the evolution of software• Key element for moving from “initial” (undefined process)
to “repeatable” (project management) stages in software systems development
• Keep track of the evolution of software– When was a change made?– Why was it made?– What exactly was changed?
• Make it possible (easier) to try out new parts and revert bad changes
• A collaboration tool for multiple developers
How?• Usually by having special software that
aids in version control• The software keeps different versions in
a repository• The developer checks out the program
onto his computer• This workspace acts as the place where
changes to the program can be made• Finally, the changes are committed to the
repository
Repository• A shared database for engineered artifacts• Avoids:
– Overwriting one developer's changes by someone else– Forgetting what changes were made in an earlier
version• Advantages:
– Freeing developer's creativity since it's easy to revert back to any change if something went wrong
– Tracking and remembering any change– Quite transparent in the development process
Repository, cont.• Additional features
– Bug-tracking systems, patch managers, mailing lists• Allows queries about configurations to be answered
– Who has a particular system version?– What platform is required for a particular version?– What versions are affected by a change to component X?– How many reported faults in version T?
• Operations– Check out (import)
• Obtain an existing version of an item from the database– Check in (commit)
• Add new version of an item into the database– It is not possible to modify existing items in the database. You
need to create a new version
Version Derivation Structure
The repository's filesystem
The repository
•Imagine an array of revision numbers, starting at 0, stretching from left to right•Each revision number has a filesystem tree hanging below it•¨Each tree is a “snapshot” of the way the repository looked after each commit.
Basic Operations• Checkout• Add a file (or directory, symlink etc..)• Remove a file• Rename a file• Committing changes• Retaining previous versions
Subversion• A better CVS• Centralized server• Supports file renaming (unlike CVS)• Changes are in fact atomic (unlike CVS)• Supports arbitrary tagging of files using
named properties– Example: the svn:ignore property of a
directory tells which files to ignore (e.g. temporary object files)
SVN Revision Numbers• Subversion's revision numbers
apply to entire trees, not individual files
• Each revision number selects an entire tree, a particular state of the repository after some committed change– Another way to think about it is
that revision N represents the state of the repository filesystemafter the Nth commit
– When a Subversion user talks about “revision 5 of foo.c”, they really mean “foo.c as it appears in revision 5.”
• Notice that in general, revisions N and M of a file do not necessarily differ!
Checkout• svn checkout http://hera.cs.abo.fi:8080/lab1_2005/luka_course_project
checks out the Luka’s course assignment
• Every directory has a special .svn directory containing metadata about the project
Basic Work Cycle1. Update your working copy
– svn update2. Make changes
– svn add– svn delete– svn copy– svn move
3. Examine your changes– svn status– svn diff– svn revert
4. Merge others' changes– svn merge– svn resolved
5. Commit your changes– svn commit
! If you are not adding new files, but only modifying the existing ones, you only need 2 commands:
– svn update and svn commit
• Examining History– svn log
• Shows you broad information: log messages attached to revisions, and which paths changed in each revision
– svn diff • Shows you the specific details of how a
file changed over time– svn cat
• This is used to retrieve any file as it existed in a particular revision number and display it on your screen
– svn list • Displays the files in a directory for any
given revision• Other Useful Commands
– svn cleanup• If Subversion ever tells you that some
part of your working copy is “locked”, then this is the command that you should run
– svn import• a quick way to copy an unversioned
tree of files into a repository, creating intermediate directories as necessary
When to Commit• Preferably: One idea – One commit• When substantial work has been made (your own
computer's harddisk might not be backuped)• Checkpointing the current code so you can try
different additions• Don't mix several different changes
– Harder to understand what parts of the change are connected
– Individual parts in a change are harder to revert
Tags• Tags are explicitely named snapshots of the
project.• Useful for making an external release so that you
remember exactly what you have shipped– Tag your solutions (next slide)– In general: bug reports from customers are then
analyzed by checking out the specific tag• In subversion, this is done by copying, e.g. “svn
cp myproject tags/0.1”
Your Repository Layout In Subversion
• Directories– myproject– myproject/trunk – for files and unit tests– myproject/solutionN – for the solutions
• Solutions: tag when done– svn copy
http://[YOUR_REPOSITORY]/myproject/trunk \http://[YOUR_REPOSITORY]/myproject/solution1 \-m “Assignment 1 completed“
Subclipse
Adding a project to version control
Subclipse, checkout from repository
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Subclipse, cont.
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