The Python environment¶
The default Data Science Studio installation builds a Python virtual environment (virtualenv) which contains all packages required for Data Science Studio operation.
If you need to install additional third-party Python packages (to make them available to notebooks and recipes),
you must use the command
DATA_DIR/bin/pip, where DATA_DIR is the Studio data directory.
$ DATA_DIR/bin/pip list $ DATA_DIR/bin/pip install PKG
As usual with Python package installation on Linux, you may need to install additional system dependencies if the target Python packages include native code. In particular you may need the system development tools (“build-essentials” on Debian/Ubuntu, “@Development tools” on RedHat/CentOS) and the Python interpreter header files (“python-dev” on Debian/Ubuntu, “python27-devel” on RedHat/CentOS 6.x, “python-devel” on RedHat/CentOS 7.x).
Using the system’s pip command will not work. Data Science Studio’s Python environment is fully isolated.
In addition to the above, you can add locally-managed Python code and resources in directory
This directory is created but left empty by the Data Science Studio installer, and is included in the Python
search path for both notebooks and recipes. You can use it to deploy additional Python modules used by your code
but not managed by pip.
The additional Python packages installed by
DATA_DIR/bin/pip or added to
DATA_DIR/lib/python are preserved
by DSS upgrades.
Using this mechanism to upgrade or locally reinstall one of the standard Python packages shipped with DSS is not supported, and is likely to break DSS code in subtle manners, as more often than not backwards compatibility is incomplete. This is especially the case with the heavyweight packages of the Scientific Python suite (numpy, scipy, scikit-learn, pandas).
Data Science Studio requires a Python 2.7 interpreter. As part of the standard DSS installation, the presence of the distribution default packages for Python 2.7 is checked and if necessary those are pulled by the dependency installation phase.
On CentOS and RedHat 6.x, where the system’s version of Python is 2.6, Python 2.7 is pulled from the additional repository IUS (http://iuscommunity.org/pages/Repos.html).
The installation script locates the Python interpreter to use by looking up
python2.7 in the standard PATH.
It then proceeds to build a Python virtual environment on top of this interpreter, containing the standard Python
packages shipped with Data Science Studio.
Data Science Studio uses this virtual environment to run all Python code, including IPython notebooks and Python dataset manipulation recipes.
DATA_DIR/bin/pip command can be used to list or otherwise manage the contents of this virtual environment, as described above.
For testing purposes, the Python virtual environment used by DSS can be launched with
If several Python 2.7 systems are available on your server, you can control which one is used by DSS by adjusting the PATH environment variable
of the DSS Unix user account so that it is found by command
python2.7. You should NOT use environment variable
DKUPYTHONBIN for this as
this would switch to a different advanced installation mode, described below.
The native libraries of the standard Python packages shipped with DSS are built using UCS-4 Unicode characters. Make sure the
default Python interpreter used by DSS has been built with
--enable-unicode=ucs4. This is the default on most recent
Linux distributions, but it is not the default when building Python interpreters directly from source.
It is possible to rebuild the Python virtual environment, if necessary. This is the case if you moved or renamed Data Science Studio’s data directory, as Python virtual environments embed their full directory name. This may be also be the case if you want to reset the virtualenv to a pristine state following installation / desinstallation of additional packages.
The Python virtualenv is automatically created by the installer when it is not present. The sequence of operations to reinitialize it thus consists in removing the virtualenv and reinstalling DSS, keeping track of any local package which you want to reinstall afterwards:
# Stop Data Science Studio DATADIR/bin/dss stop # Save the list of locally-installed packages DATADIR/bin/pip freeze -l >dss-local-packages.txt # Remove the virtualenv, keeping backup mv DATADIR/pyenv DATADIR/pyenv.backup # Reinstall Data Science Studio (upgrade mode) dataiku-dss-VERSION/installer.sh -d DATADIR -u # Review and possibly edit the list of locally-installed packages vi dss-local-packages.txt # Reinstall local packages DATADIR/bin/pip install -r dss-local-packages.txt # Start Data Science Studio DATADIR/bin/dss start # When everything is considered stable, remove the backup rm -rf DATADIR/pyenv.backup
For non-standard needs, you can force Data Science Studio to use an externally-maintained Python 2.7 installation by defining the DKUPYTHONBIN environment variable for the Linux user account running the Studio.
Using this mode is not officially supported.
This variable points to the Python binary to use. It should be defined before running the installer, and for all subsequent runs of the Studio startup or management scripts. You would typically define it as follows:
$ echo "export DKUPYTHONBIN=/usr/local/bin/python" >>$HOME/.profile
When this variable is defined, the precompiled third-party Python packages shipped with DSS are not used. You must make sure that the
interpreter started by
$DKUPYTHONBIN contains all packages required by DSS. Please refer to the script
INSTALL_DIR/scripts/install/install-python-packages.sh, found in the Data Science Studio installation directory, for this purpose.