ElementsEnv is a python package that can be used as a companion software for the development of Elements-based software projects. It allows to builds and use several version of the same project in a consistent way.

For this purpose, ElementsEnv provides 2 executables:

• ELogin that sets up the build environment. It has to be called before anything else and it might be interesting to have called by the shell login script. Please have a look at the user manual for more details.
• E-Run (ERun) that enables to call the executable of any version of any reachable project

Quick Install

Once the source tarball has been downloaded and expanded, the user installation of the software can be done with the usual setup.py script.

python setup.py install --user

This will perform the installation in various sub-directories of the home directory of the user. This will install the ELogin and E-Run scripts. More installation options are described at this section of the user manual.

Setup

1. After this installation, the executables are placed in the ~/.local/bin directory. Therefore, this directory has to be preprended manually to the PATH environment variable in the profile script of the user's shell (.bash_profile for bash and .login for tcsh).

2. To initialize the build environment (and thus being able to access the E-Run command and the ELogin alias), the ELogin.sh (or ELogin.csh for the csh shell family) needs to be sourced.

   • For the bash shell family (bash, zsh), there are 2 possibilities:

     source ~/.local/bin/ELogin.sh
     

     or

     . ELogin.sh
     

     The . command will do the lookup in the PATH environment variable, but the source command doesn't.
   • For the csh shell family (csh, tcsh):

     source ~/.local/bin/ELogin.csh
     

     After the sourcing above, the ELogin alias will be available. It will facilitate the sourcing of the ELogin.sh file and looks like:

     alias ELogin="source `which ELogin.sh`"
     

     alias ELogin "source `which ELogin.csh`"
     

Usage

After the setup done by the sourcing of ELogin.sh, the E-Run command will be available. It allows to call any executable for the Elements-based projects located in the CMAKE_PROJECT_PATH. This environment variable defaults to ~/Work/Projects:/opt. The trailing /opt location can be tuned at the insallation time of the ElmeentsEnv package. Please have a look at the user manual for more details.

The call to any executable of a specific version of a given project is then:

E-Run MyProject 1.2 MyExec arg1 arg2 ...

The locations of the source trees of the various projects would look like, in general:

~/Work/Projects/MyProject/1.2
~/Work/Projects/MyProject/1.3
/opt/MyProject/1.0
/opt/MyProject/1.2
/opt/MySecondProject/0.1
...

Remarks

• The lookup is always done in the order of the CMAKE_PROJECT_PATH locations. The fist match wins.
• The version sub-directory is not mandatory. The project root can be simply located at ~/Work/Projects/MyProject. In that case, obviously, only one version of the project MyProject can be used. It is only possible in the ~/Work/Projects location (and not in the /opt location).
• The version keyword in the E-Run command line can be ommitted:

  E-Run MyProject MyExec arg1 arg2 ...
  

  In that situation, either the highest version of the project in the current location is selected or the versionless project.

---

Packaging

1. In order to create the source tarball suitable for the creation of RPM, 2 commands are possible:

   git archive --format=tar.gz --prefix=ElementsEnv-0.2/ --output $(rpm --eval "%_sourcedir")/ElementsEnv-0.2.tar.gz 0.2
   

   or

   python setup.py sdist
   

   This last command also generates the needed RPM spec file for the RPM package creation in the dist sub-directory.

2. Please note that this setup.py script cannot be used for the RPM creation directly. the "python setup.py bdist_rpm" doesn't equip the spec file with the proper post install command. The RPM spec file is generated from a template located in the data/RPM sub-directory.

   The RPM packages can then be created with

   # cp dist/ElementsEnv-0.2.tar.gz $(rpm --eval "%_sourcedir")/
   # cp dist/ElementsEnv.spec $(rpm --eval "%_specdir")/
   # cd ElementsEnv-0.2.tar.gz
   # rpmbuild -ba ElementsEnv.spec
   

Installation

1. The created RPM file is relocatable through 3 folders

   rpm -Uvh --relocate /etc/=/home/hubert/.local/tmp/testrpm \
            --relocate /usr=/home/hubert/.local/tmp/testrpm \
            --relocate /opt=/home/hubert/.local/tmp/testrpm
            ../RPMS/noarch/ElementsEnv-0.3-1.fc19.noarch.rpm
   

2. The direct installation with the "python setup.py install" support several schemes (--home, --prefix, --root, --user) and options. The schemes are the default ones supported by the python distutils package and the special options are:

   • --skip-custom-postinstall: to avoid the postinstall treatment. Useful when creating RPMs
   • --elementsenv-base: to specify the native ElementsEnv Software installation base. This will trigger a post install script to hardcode the location in the scripts. The default location is /opt.

   Typical call are:

   1. python setup.py install --user --elementsenv-base=/my/custom/dir

      That will use the common user python installation for ElementsEnv and set the default ElementsEnv software location to /my/custom/dir

      By default, python setup.py install --user will use /opt for the default installation of the Elements-based software projects that this package will manage.

      ElementsEnv itself, in the case of the --user option will install its executables in the ~/.local/bin directory. In order to be able to access them, that directory needs to be added to the PATH environment variable in the user's login script.

   2. python setup.py install --prefix=~/Work/Env --elementsenv-base=/my/custom/dir

      This will do the same as the previous one, except that the very installation of the ElementsEnv package will be done at a custom prefix location.