7. Examples¶
This chapter provides a number of basic examples to help get started with distutils. Additional information about using distutils can be found in the Distutils Cookbook.
See also
- Distutils Cookbook
- Collection of recipes showing how to achieve more control over distutils.
7.1. Pure Python distribution (by module)¶
If you’re just distributing a couple of modules, especially if they don’t live
in a particular package, you can specify them individually using the
py_modules option in the setup script.
In the simplest case, you’ll have two files to worry about: a setup script and
the single module you’re distributing, foo.py in this example:
<root>/
setup.py
foo.py
(In all diagrams in this section, <root> will refer to the distribution root directory.) A minimal setup script to describe this situation would be:
from distutils.core import setup
setup(name='foo',
version='1.0',
py_modules=['foo'],
)
Note that the name of the distribution is specified independently with the
name option, and there’s no rule that says it has to be the same as
the name of the sole module in the distribution (although that’s probably a good
convention to follow). However, the distribution name is used to generate
filenames, so you should stick to letters, digits, underscores, and hyphens.
Since py_modules is a list, you can of course specify multiple
modules, eg. if you’re distributing modules foo and bar, your
setup might look like this:
<root>/
setup.py
foo.py
bar.py
and the setup script might be
from distutils.core import setup
setup(name='foobar',
version='1.0',
py_modules=['foo', 'bar'],
)
You can put module source files into another directory, but if you have enough modules to do that, it’s probably easier to specify modules by package rather than listing them individually.
7.2. Pure Python distribution (by package)¶
If you have more than a couple of modules to distribute, especially if they are
in multiple packages, it’s probably easier to specify whole packages rather than
individual modules. This works even if your modules are not in a package; you
can just tell the Distutils to process modules from the root package, and that
works the same as any other package (except that you don’t have to have an
__init__.py file).
The setup script from the last example could also be written as
from distutils.core import setup
setup(name='foobar',
version='1.0',
packages=[''],
)
(The empty string stands for the root package.)
If those two files are moved into a subdirectory, but remain in the root package, e.g.:
<root>/
setup.py
src/ foo.py
bar.py
then you would still specify the root package, but you have to tell the Distutils where source files in the root package live:
from distutils.core import setup
setup(name='foobar',
version='1.0',
package_dir={'': 'src'},
packages=[''],
)
More typically, though, you will want to distribute multiple modules in the same
package (or in sub-packages). For example, if the foo and bar
modules belong in package foobar, one way to layout your source tree is
<root>/
setup.py
foobar/
__init__.py
foo.py
bar.py
This is in fact the default layout expected by the Distutils, and the one that requires the least work to describe in your setup script:
from distutils.core import setup
setup(name='foobar',
version='1.0',
packages=['foobar'],
)
If you want to put modules in directories not named for their package, then you
need to use the package_dir option again. For example, if the
src directory holds modules in the foobar package:
<root>/
setup.py
src/
__init__.py
foo.py
bar.py
an appropriate setup script would be
from distutils.core import setup
setup(name='foobar',
version='1.0',
package_dir={'foobar': 'src'},
packages=['foobar'],
)
Or, you might put modules from your main package right in the distribution root:
<root>/
setup.py
__init__.py
foo.py
bar.py
in which case your setup script would be
from distutils.core import setup
setup(name='foobar',
version='1.0',
package_dir={'foobar': ''},
packages=['foobar'],
)
(The empty string also stands for the current directory.)
If you have sub-packages, they must be explicitly listed in packages,
but any entries in package_dir automatically extend to sub-packages.
(In other words, the Distutils does not scan your source tree, trying to
figure out which directories correspond to Python packages by looking for
__init__.py files.) Thus, if the default layout grows a sub-package:
<root>/
setup.py
foobar/
__init__.py
foo.py
bar.py
subfoo/
__init__.py
blah.py
then the corresponding setup script would be
from distutils.core import setup
setup(name='foobar',
version='1.0',
packages=['foobar', 'foobar.subfoo'],
)
7.3. Single extension module¶
Extension modules are specified using the ext_modules option.
package_dir has no effect on where extension source files are found;
it only affects the source for pure Python modules. The simplest case, a
single extension module in a single C source file, is:
<root>/
setup.py
foo.c
If the foo extension belongs in the root package, the setup script for
this could be
from distutils.core import setup
from distutils.extension import Extension
setup(name='foobar',
version='1.0',
ext_modules=[Extension('foo', ['foo.c'])],
)
If the extension actually belongs in a package, say foopkg, then
With exactly the same source tree layout, this extension can be put in the
foopkg package simply by changing the name of the extension:
from distutils.core import setup
from distutils.extension import Extension
setup(name='foobar',
version='1.0',
ext_modules=[Extension('foopkg.foo', ['foo.c'])],
)
7.4. Checking a package¶
The check command allows you to verify if your package meta-data
meet the minimum requirements to build a distribution.
To run it, just call it using your setup.py script. If something is
missing, check will display a warning.
Let’s take an example with a simple script:
from distutils.core import setup
setup(name='foobar')
Running the check command will display some warnings:
$ python setup.py check
running check
warning: check: missing required meta-data: version, url
warning: check: missing meta-data: either (author and author_email) or
(maintainer and maintainer_email) must be supplied
If you use the reStructuredText syntax in the long_description field and
docutils is installed you can check if the syntax is fine with the
check command, using the restructuredtext option.
For example, if the setup.py script is changed like this:
from distutils.core import setup
desc = """\
My description
==============
This is the description of the ``foobar`` package.
"""
setup(name='foobar', version='1', author='tarek',
author_email='tarek@ziade.org',
url='http://example.com', long_description=desc)
Where the long description is broken, check will be able to detect it
by using the docutils parser:
$ python setup.py check --restructuredtext
running check
warning: check: Title underline too short. (line 2)
warning: check: Could not finish the parsing.
7.5. Reading the metadata¶
The distutils.core.setup() function provides a command-line interface
that allows you to query the metadata fields of a project through the
setup.py script of a given project:
$ python setup.py --name
distribute
This call reads the name metadata by running the
distutils.core.setup() function. Although, when a source or binary
distribution is created with Distutils, the metadata fields are written
in a static file called PKG-INFO. When a Distutils-based project is
installed in Python, the PKG-INFO file is copied alongside the modules
and packages of the distribution under NAME-VERSION-pyX.X.egg-info,
where NAME is the name of the project, VERSION its version as defined
in the Metadata, and pyX.X the major and minor version of Python like
2.7 or 3.2.
You can read back this static file, by using the
distutils.dist.DistributionMetadata class and its
read_pkg_file() method:
>>> from distutils.dist import DistributionMetadata
>>> metadata = DistributionMetadata()
>>> metadata.read_pkg_file(open('distribute-0.6.8-py2.7.egg-info'))
>>> metadata.name
'distribute'
>>> metadata.version
'0.6.8'
>>> metadata.description
'Easily download, build, install, upgrade, and uninstall Python packages'
Notice that the class can also be instanciated with a metadata file path to loads its values:
>>> pkg_info_path = 'distribute-0.6.8-py2.7.egg-info'
>>> DistributionMetadata(pkg_info_path).name
'distribute'