General comments

For the purpose of converting SVN repo to GIT I’ve used a local Xubuntu 14.04 64bit machine.

Prerequisites:

• librarian access to SVN repo (in our case it will be libtotsw account)
• write access to empty GIT repository (in our case it will be repository called cms-totem-offline)

We will also need 3 directories:

• svn2git where conversion tool will be compiled
• svnrepo directory with whole SVN repo to be converted
• gitrepo directory where conversion will take place

Migration procedure

Fetching SVN repository

Using librarian account, fetch whole SVN repository to svnrepo directory

mkdir svnrepo
rsync -avz libtotsw@lxplus.cern.ch:/afs/cern.ch/project/svn/reps/totem/ svnrepo/

(...)
sent 349,296 bytes  received 1,117,648,102 bytes  2,697,219.30 bytes/sec
total size is 1,173,106,973  speedup is 1.05
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1655) [generator=3.1.0]

rsync will complain, as some of the files cannot be copied (i.e. hooks/*.tmpl ). Ignore it.

Preparing conversion tool

Having some troubles with ruby svn2git tool (https://github.com/nirvdrum/svn2git) I decided to use simpler tool (https://gitorious.org/svn2git), working on local copies. For the purpose of migration I used version 1.0.10 which needed some fixes.

Run following commands to download and compile svn2git tool.

git clone git://gitorious.org/svn2git/svn2git.git
cd svn2git
git checkout 1.0.10
qmake -project
qmake
make

You might expect following output:

(...)
g++ -c -m64 -(...) QtCore -I. -o main.o src/main.cpp
src/main.cpp: In function ‘int main(int, char**)’:
src/main.cpp:158:37: error: ‘VER’ was not declared in this scope
         printf("Git version: %s\n", VER);
                                     ^
make: *** [main.o] Error 1

Fix Makefile by adding paths to libraries:

INCPATH       = -I/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++-64 -I. -I. -Isrc -I/usr/include/qt5 -I/usr/include/qt5/QtGui -I/usr/include/qt5/QtCore -I/usr/include/subversion-1/ -I/usr/include/apr-1.0/ -I.
LIBS          = $(SUBLIBS) -L/usr/X11R6/lib64 -lQt5Gui -L/usr/lib/x86_64-linux-gnu -lQt5Core -lGL -lpthread -lsvn_fs-1 -lsvn_subr-1 -lapr-1 -lsvn_repos-1

Fix src/main.cpp by removing line 158 (printf("Git version: %s\n", VER);)

make

Compilation will produce many warnings, simply ignore them.

Migration

Go to gitrepo directoryL

cd ..
mkdir gitrepo
cd gitrepo

svn2git need a set of rules (you can think of them as of mapping between SVN and GIT structure). For every directory there should be a corresponding rule, otherwise svn2git will complain.

Here we provide a set of rules which will copy all contents of SVN repository into new local GIT repository called full and a single branch from SVN into another local GIT repository called part. Note that SVN repository structure had in past one element outside normal structure (/dbpop).

Copy template of rules file to local directory

cp ../svn2git/samples/standardlayout.rules subdir.rules

Edit subdir.rules to have following content:

create repository full
end repository

create repository part
end repository

match /branches/CMSSW_6_2_0/offline/cmssw/src/
  repository part 
  branch master
end match

match /trunk/
  repository full
  branch master
end match

match /branches/([^/]+)/
  repository full
  branch \1
end match

match /tags/([^/]+)/
  repository full
  branch refs/tags/\1
end match

match /
end match

Run conversion tool (might take some time):

../svn2git/svn2git --identity-domain cern.ch --rules subdir.rules --add-metadata ../svnrepo/

Now it is time to push newly created repo to remote GIT repo at CERN, let us do it with repo called part:

cd part
git remote add origin https://git.cern.ch/reps/cms-totem-offline
git push --all
git push --tags

Hints

• default size of newly created repo at CERN is 100MB. If you are planning to migrate larger structure, increase GIT repo size first.
• if something goes wrong and you are planning to clean GIT repo, read this first: Knowledge Base Article: KB0002015 and StackOverflow article
• Let us assume you have Fisheye linked to GIT repo. If you remove something from GIT it will be still visible in Fisheye. You need to request Re-indexing by sending a message to administrators.