Published on September 29, 2008
Version Control with SVN by Michelangelo van Dam PHPBelgium meeting 22/10/2008 Cafe Sport Leuven 1 1
About me Michelangelo van Dam Enterprise PHP Consultant Zend Certified Engineer Co-founder PHPBelgium Contributor Zend Framework PHP Advocate E-mail: email@example.com Blog: http://dragonbe.com Twitter: http://twitter.com/DragonBe 2 2
About this presentation • Concepts of version control • Management with subversion • Life cycle of a project in subversion • Parts and structures within subversion • Advanced subversion tools • New in release 1.5 3 3
What is version control ? “Revision control (also known as version control ...) is the management of multiple revisions of the same unit of information.” (source: Wikipedia:RevisionControl) 4 4
Version Control for PHP devs... • version control provides – management of versions of information • code/tests • configuration files • documentation – in a structured, standardized way – with repositories • centralized (SVN, CVS) • decentralized (GIT) 5 5
Why need version control ? • enables collaboration between developers • centralized “main code” (trunk) • custom code alongside main code (branching) • eases release management (tags) • rollback to previous revisions • integration with other tools 6 6
Subversion (SVN) • Subversion (http://subversion.tigris.org) • more advanced than CVS • less complex than GIT • integrates well with other tools (trac, gforge, jira, ...) • supported by many tools (Zend Studio, TurtoiseSVN, Subversion CLI) 7 7
An example project in trac 8 8
SVN browser in Zend Studio 9 9
Code management with SVN • many developers create much code • code is committed to a central repository – conflicts trigger warnings • user and groups can be defined • different versions can co-exist • access management for named and anonymous access rights 10 10
Subversion authentication • svnserve daemon $ svn svn://server/project/trunk • svnserve daemon over SSH $ svn svn+ssh://server/project/trunk • Apache webserver http://svn.server/project/trunk 11 11
Version management • all code resides in “trunk” • code version are detached in “branches” • snapshots for releases are “tagged” 12 12
Release management • a release is a snapshot of a version branch • are being deployed to server environments • for live or production environments don’t check out in document root ! – use release folders svn co svn://server/myproj/tags/rel-1.0 /web/myproj-rel-1.0 – create symlink to it ln -s /web/myproj-rel-1.0 /web/myproj 13 13
SVN life cycle custom dev branch v1.0 v1.1 Trunk bug fix rel-1.1.1 rel-1.1.2 rel-1.0.1 rel-1.0.2 14 14
Trunk • trunk is where all code resides – except custom development • has always the latest version • is not always the most stable version 15 15
Branch • two kind of branches exists – custom development branches – version branches 16 16
Custom development • code that changes many things in trunk • are best put in a separate branch • maintained by their developer(s) • and merged back into trunk – after the merge, the branch is removed • when changes are done and tested 17 17
Versions • are maintained in branches • have a long lifetime cycle (several years) • differ from each other – because of new code base, framework, language • have a common base = trunk • fixes from versions go into trunk • back port fixes go from trunk into version 18 18
Tags • tags are snapshots • usually made on version branches • can also be made on “trunk” • are deployed (exported) to staging environments • are used to keep track what’s happened between releases (change log) 19 19
More than just version control • Subversion provides more features – File portability – Keyword substitution – Locking – Externals – Peg and Operative revisions – Network model – Hooks 20 20
File portability • Line endings differ on different OSses – are ignored when checking modifications • Mime-types differ from their extensions – binary and non-binary files are tested on content 21 21
Keyword substitution • Only a few keywords are substitute – $Date:$ › $Date: 2008-10-22 20:00:00 +0100 (Wed, 22 Oct 2008) $ – $Revision:$ › $Revision: 144 $ – $Author:$ › $Author: svnusername $ – $HeadUrl:$ › $HeadUrl: http://svn.test.be/trunk $ – $Id:$ › $Id: file.php 148 2008-10-22 20:00:00Z svnusername $ 22 22
Locking • working copy locks – exclusive right to a working copy – clears with “svn cleanup” • database locks – ensures database integrity – only admins can remove this lock 23 23
Externals • Externals provide an easy way to – include other internal or external projects – without having to care about there revisions • Examples: – Zend Framework as svn:externals on library path – project that includes many smaller projects 24 24
Peg and Operative revisions • automated handling of – moving files – deleting and creating new files with same name • Using specific syntax – $ svn command -r OPERATIVE-REV item@PEG-REV 25 25
Network model • Can run it’s own svnserve – pros: no dependencies, works with ssh for extra security – contras: need svnclient to connect • Or in combination with Apache webserver – pros: works with any http-client – contras: overkill for small projects, requires mod_dav_svn, more difficult to set up 26 26
Hooks • Hooks facilitate actions to be taken – before a commit starts (validate rights) – after a commit (send e-mail, update tracker, ...) – before or after a revision change (notifications) • Can easily be incorporated with tools – tracking tools – integration tools (Lorna Jane’s Nabaztag) – mailing and logging systems 27 27
Hooks execute moments • basic commit moments: – start-commit: • runs before commit transaction started – pre-commit: • runs right before commit transaction is promoted – post-commit: • runs after the commit transaction is finished – ... 28 28
Cool things with SVN hooks Lorna Jane’s Nabaztag Responding on SVN commits http://www.flickr.com/photos/lornajane/2592602734/ 29 29
New features in Subversion v1.5 • Merge tracking (foundational) • Sparse checkouts (via new --depth option) • Interactive conflict resolution • Changelist support • Relative URLs, peg revisions in svn:externals • Cyrus SASL support for ra_svn and svnserve • ... (more on http://subversion.tigris.org/ svn_1.5_releasenotes.html) 30 30
Summary • manageable file change history • better collaboration between developers • clearer release management • more then one version of same code base • easier to rollback in case of emergency 31 31
Thank you... Questions ? Michelangelo van Dam - firstname.lastname@example.org http://slideshare.net/PHPBelgium/version-control-with-svn-presentation 32 32
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