Parasitic metaprojects¶
It is sometimes convenient to add projects to a preexisting, read-only metaproject, for example, to add a private analysis project to an IceRec release distributed via CVMFS. The cmake project includes a second, “parasitic” build system for this purpose. To create a parasitic metaproject, start by creating and empty source directory and adding the cmake project:
> mkdir -p ~/i3/icetray && cd ~/i3/icetray
> git clone https://github.com/icecube/icetray.git src
> mkdir ../psrc && cd ../psrc
Then, add a CMakeLists.txt file with the following contents:
cmake_minimum_required(VERSION 2.6.4 FATAL_ERROR)
include(cmake/toplevel-parasite.cmake NO_POLICY_SCOPE)
Now, make a build directory and run cmake:
> mkdir ../build && cd ../build
> cmake ../src -DMETAPROJECT=/path/to/build/directory -DCMAKE_INSTALL_PREFIX=icerec-plus.${OS_ARCH}
-- The C compiler identification is AppleClang 6.0.0.6000054
-- The CXX compiler identification is AppleClang 6.0.0.6000054
...
--
-- Configuring parasitic metaproject
--
-- Base metaproject: /Users/jakob/Documents/IceCube/metaprojects/icerec-lite/build
-- Built from: https://github.com/icecube/icetray.git
-- Install prefix: /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus.osx_10_x86_64
...
-- Configuring parasitic projects:
--
-- Syminking resources from host projects
-- Syminking Python packages from /Users/jakob/Documents/IceCube/metaprojects/icerec-lite/build/lib/icecube/
-- Symlinking binaries from /Users/jakob/Documents/IceCube/metaprojects/icerec-lite/build/bin/
-- Symlinking libraries from /Users/jakob/Documents/IceCube/metaprojects/icerec-lite/build/lib/
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/jakob/Documents/IceCube/metaprojects/parasite/build
The argument to -DMETAPROJECT can specify a pre-build metaproject
distributed via CVMFS, e.g. icerec/V04-11-10, or the full path to an
existing build directory.
At this point, you have a metaproject that consists entirely of symbolic links to the parent metaproject. A tarball created from the metaproject in this stage is extremely small:
> make tarball
Scanning dependencies of target tarball-install
[ 50%] Tarball install
Install the project...
-- Install configuration: ""
-- Installing: /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus./lib/icecube/__init__.py
-- Installing: /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus./lib/icecube/load_pybindings.py
-- Installing: /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus././env-shell.sh
Built target tarball-install
Scanning dependencies of target tarball-finish
Finishing tarball of /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus.osx_10_x86_64
Creating /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus.osx_10_x86_64.tar.gz
tar: Removing leading '/' from member names
Checksumming /Users/jakob/Documents/IceCube/metaprojects/parasite/build/icerec-plus.osx_10_x86_64.tar.gz
Built target tarball-finish
Scanning dependencies of target tarball
Built target tarball
> ls -lh icerec-plus.osx_10_x86_64.tar.gz
-rw-r--r-- 1 jakob staff 4.1K Aug 12 21:48 icerec-plus.osx_10_x86_64.tar.gz
Now you can add extra projects, for example, myproject:
> git clone https://github.com/icecube/myproject.git ../src/myproject
> make rebuild_cache
...
-- Configuring parasitic projects:
--
-- + myproject
-- +-- python [symlinks]
-- +-- myproject-pybindings
-- Syminking resources from host projects
...
> make
This metaproject will contain myproject, linked against libraries in the parent metaproject, plus symbolic links to every other project in the parent metaproject. Since the symbolic links take up virtually no disk space, the tarball of this metaproject is quite small.
