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
the debian/control
file. Exporting the variable DH_VIRTUALENV_INSTALL_ROOT=</your/custom/install/dir>
will set the install path for your package if you don’t wish to use
the default path.
Simple usecase¶
To signal debhelper to use dh-virtualenv for building your
package, you need to pass --with python-virtualenv
to debhelper
sequencer.
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.txt
in the root directory of your project. The requirements file is not mandatory.- The project must have a
setup.py
file in the root of the project. Sequencer will runsetup.py install
to 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:
-
-p
<package>
,
--package
<package>
¶ Act on the package named <package>
-
-N
<package>
,
--no-package
<package>
¶ Do not act on the specified package
-
-v
,
--verbose
¶
Turn on verbose mode. This has a few effects: it sets root logger level to
DEBUG
and passes verbose flag topip
when installing packages. This can also be provided using the standardDH_VERBOSE
environment variable.
-
--extra-index-url
<url>
¶ Use extra index url <url> when running
pip
to install packages. This can be provided multiple times to pass multiple URLs topip
. This is useful if you for example have a private Python Package Index.
-
--preinstall
<package>
¶ Package to install before processing the requirements. This flag can be used to provide a package that is installed by
pip
before processing requirements file. This is handy if you need to install for example a custom setup script or other packages needed to parsesetup.py
. This flag can be provided multiple times to pass multiple packages for pre-install.
-
--pypi-url
<URL>
¶ 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
pip
uses as default (usuallyhttp://pypi.python.org/simple
).
-
--extra-pip-arg
<PIP ARG>
¶ 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.
-
--setuptools
¶
Use setuptools instead of distribute in the virtualenv
-
--no-test
¶
Skip running
python setup.py test
after dependencies and the package is installed. This is useful if the Python code is packaged using distutils and not setuptools.
-
--python
<path>
¶ Use a specific Python interpreter found in
path
as the interpreter for the virtualenv. Default is to use the system default, usually/usr/bin/python
.
-
--builtin-venv
¶
Enable the use of the build-in
venv
module, i.e. usepython -m venv
to 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 thevenv
module, but virtualenvs created with Python 3.3 are not bootstrapped with setuptools or pip.)
-
-S
,
--use-system-packages
¶
Enable the use of system site-packages in the created virtualenv by passing the
--system-site-packages
flag tovirtualenv
.
Advanced usage¶
To provide command line options to dh_virtualenv
sequence the
override mechanism of the debhelper is the best tool.
Following 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 --with
python-virtualenv
, 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
Pyvenv
of Python 3.x is not supported- No custom arguments outside requirements.txt can be passed to
pip
- Not possible to specify custom install or build directories