subversion to git migration
DESCRIPTION
Talk I presented at the BigCommerce meetup recentlyTRANSCRIPT
SVN to Git Migration
Technology
➔ Gitolite.➔ Atlassian Suite.➔ Internal system ”Octopus”.
Migratingthe code
git-svn
➔ Slow...➔ Didn't handle shallow merges well.➔ Our old branches didn't map well.➔ Works fine for small repos.➔ Not right for our repo.
svn-all-fast-export
➔ Faster.➔ Direct access to git from C libs.➔ Easier to configure.
svn-all-fast-export# rulesmapcreate repository bigcommerceend repository
match /trunk/ repository bigcommerce branch master
end match...
match /branches/([^/]+)/repository bigcommercebranch \1
end match...
match /tags/7.3.23/repository bigcommercebranch refs/tags/7.3.23annotated true
end match
svn-all-fast-export# svnauthorsanna.pomroy = Anna Pomroy <[email protected]>chris.beckett = Chris Beckett <[email protected]>chris.boulton = Chris Boulton <[email protected]>
...
# import commandsvnallfastexport identitymap svnauthors rules map addmetadata /var/svn/bigcommerce
svn-all-fast-export
➔ Problem: Post migration branch amnesia. Only affected some branches.
➔ Solution(s): Patch from the original svn branch. Rebranch in git, resolve lots of conflicts and
pay close attention!
svn-all-fast-export
➔ Problem: Wrong revision used to create a branch on
import.➔ Solution:
Fix it in the source & submit a patch! Check & double check...
How are we using git?
SVN branching model
Trunk
Feature-X
RC-01
Feature-Y
1.0 1.2
MonTues MonTues
Time
Stability
RC-02
Hot
fix
Gitflow branching model
Develop
Feature/x
Release/1.0
Feature/y
1.0
1.3
MonTues MonTues
Time
Stability
Release/1.3
master
1.2 1.3
Rome wasn'tbuilt in a day...
Identified issues
➔ svn:ignore. Create .gitignore
➔ Empty directories. Fill with .empty files
➔ Commit hooks. Use gitty for hook management.
Unidentified problems
➔ ”Time & tide waits for no man”. We were fixing the deployment system
”Octopus” on the day. Last minute cherry-picks to tags/branches to
get them working.
Why did we do it?
”f**k; I keep typing git status”
”Maybe we should evaluate git more”
”...what if anything is blocking us from
switching to git for source control?”
”I miss my git staging area already”
Immediate Benefits
➔ Decentralised, remote work.➔ Much, much faster.➔ Staged commits, stashes.➔ Flexible & powerful cmd line.
Questions?