Building packages with dh-virtualenv¶
Building packages with dh-virtualenv is relatively easy to start with but it also supports lot of customization to fit in your general needs.
By default, dh-virtualenv installs your packages under
/usr/share/python/<packagename>. The package name is provided by
debian/control file. Exporting the variable
will set the install path for your package if you don’t wish to use
the default path.
To signal debhelper to use dh-virtualenv for building your
package, you need to pass
--with python-virtualenv to debhelper
In a nutshell, the simplest
debian/rules file to build using
dh-virtualenv looks like this:
#!/usr/bin/make -f %: dh $@ --with python-virtualenv
However, the tool makes a few assumptions of your project’s structure:
- For installing requirements, you need to have a file called
requirements.txtin the root directory of your project. The requirements file is not mandatory.
- The project must have a
setup.pyfile in the root of the project. Sequencer will run
setup.py installto install the package inside the virtualenv.
After these are place, you can just build the package with your favorite tool!
Command line options¶
To change the default behavior the
dh_virtualenv command accepts a
few command line options:
Act on the package named <package>
Do not act on the specified package
Turn on verbose mode. This has a few effects: it sets root logger level to
DEBUGand passes verbose flag to
pipwhen installing packages. This can also be provided using the standard
Use extra index url <url> when running
pipto install packages. This can be provided multiple times to pass multiple URLs to
pip. This is useful if you for example have a private Python Package Index.
Package to install before processing the requirements. This flag can be used to provide a package that is installed by
pipbefore processing requirements file. This is handy if you need to install for example a custom setup script or other packages needed to parse
setup.py. This flag can be provided multiple times to pass multiple packages for pre-install.
Base URL of the PyPI server. This flag can be used to pass in a custom URL to a PyPI mirror. It’s useful if you for example have an internal mirror of the PyPI or you run a special instance that only exposes selected packages of PyPI. If this is not provided, the default will be whatever
pipuses as default (usually
Extra parameters to pass to the pip executable. This is useful if you need to change the behaviour of pip during the packaging process. You can use this flag multiple times to pass in different pip flags. As an example passing in –extra-pip-arg “–no-compile” to the override_dh_virtualenv section of the debian/rules file will disable the generation of pyc files.
Use setuptools instead of distribute in the virtualenv
python setup.py testafter dependencies and the package is installed. This is useful if the Python code is packaged using distutils and not setuptools.
Use a specific Python interpreter found in
pathas the interpreter for the virtualenv. Default is to use the system default, usually
Enable the use of the build-in
venvmodule, i.e. use
python -m venvto create the virtualenv. For this to work, requires Python 3.4 or later to be used, e.g. by using the option
--python /usr/bin/python3.4. (Python 3.3 has the
venvmodule, but virtualenvs created with Python 3.3 are not bootstrapped with setuptools or pip.)
Enable the use of system site-packages in the created virtualenv by passing the
To provide command line options to
dh_virtualenv sequence the
override mechanism of the debhelper is the best tool.
debian/rules will provide http://example.com as
additional Python Package Index URI:
#!/usr/bin/make -f %: dh $@ --with python-virtualenv override_dh_virtualenv: dh_virtualenv --extra-index-url http://example.com
Experimental buildsystem support¶
Important: Following chapters describe a completely experimental functionality of dh-virtualenv.
Latest HEAD of the dh-virtualenv has a buildsystem alterantive. The
main difference in use is that instead of the
debian rules file should look like this:
#!/usr/bin/make -f %: dh $@ --buildsystem=dh_virtualenv
Using the buildsystem instead of the part of the sequence (in other
words, instead of the
--with python-virtualenv) one can get more
flexibility into the build process.
Flexibility comes from the fact that buildsystem will have individual
steps for configure, build, test and install and those can be
overridden by adding
override_dh_auto_<STEP> target into the
debian/rules file. For example:
#!/usr/bin/make -f %: dh $@ --buildsystem=dh_virtualenv override_dh_auto_test: py.test test/
In addition the separation of build and install steps makes it
possible to use
debian/install files to include built files into
the Debian package. This is not possible with the sequencer addition.
Known incompabilities of the buildsystem¶
This section defines the known incompabilities with the sequencer approach. There are no guarantees that these all get addressed, but most of them, if not all, probably will.
- No custom Python interpreter supported
Pyvenvof Python 3.x is not supported
- No custom arguments outside requirements.txt can be passed to
- Not possible to specify custom install or build directories