6 Creating Built Distributions
A ``built distribution'' is what you're probably used to thinking of either as a ``binary
package'' or an ``installer'' (depending on your background). It's not necessarily binary,
though, because it might contain only Python source code and/or byte-code; and we don't call
it a package, because that word is already spoken for in Python. (And ``installer'' is a term
specific to the Windows world. ** do Mac people use it? **)
A built distribution is how you make life as easy as possible for installers of your module
distribution: for users of RPM-based Linux systems, it's a binary RPM; for Windows users, it's
an executable installer; for Debian-based Linux users, it's a Debian package; and so forth.
Obviously, no one person will be able to create built distributions for every platform under
the sun, so the Distutils are designed to enable module developers to concentrate on their
specialty--writing code and creating source distributions--while an intermediary species
called packagers springs up to turn source distributions into built distributions for
as many platforms as there are packagers.
Of course, the module developer could be his own packager; or the packager could be a
volunteer ``out there'' somewhere who has access to a platform which the original developer
does not; or it could be software periodically grabbing new source distributions and turning
them into built distributions for as many platforms as the software has access to. Regardless
of who they are, a packager uses the setup script and the bdist command family to
generate built distributions.
As a simple example, if I run the following command in the Distutils source tree:
then the Distutils builds my module distribution (the Distutils itself in this case), does
a ``fake'' installation (also in the build directory), and creates
the default type of built distribution for my platform. The default format for built
distributions is a ``dumb'' tar file on Unix,
and a simple executable installer on Windows. (That tar file is considered ``dumb'' because it
has to be unpacked in a specific location to work.)
Thus, the above command on a Unix system
creates Distutils-1.0.plat.tar.gz;
unpacking this tarball from the right place installs the Distutils just as though you had
downloaded the source distribution and run python setup.py install. (The ``right
place'' is either the root of the filesystem or Python's prefix
directory, depending on the options given to the bdist_dumb command; the default
is to make dumb distributions relative to prefix.)
Obviously, for pure Python distributions, this isn't any simpler than just running python
setup.py install--but for non-pure distributions, which include extensions that would
need to be compiled, it can mean the difference between someone being able to use your
extensions or not. And creating ``smart'' built distributions, such as an RPM package or an
executable installer for Windows, is far more convenient for users even if your distribution
doesn't include any extensions.
The bdist command has a --formats option, similar to
the sdist command, which you can use to select the types of built distribution to
generate: for example,
python setup.py bdist --format=zip
would, when run on a Unix system, create Distutils-1.0.plat.zip--again, this
archive would be unpacked from the root directory to install the Distutils.
The available formats for built distributions are:
gztar |
gzipped tar file (.tar.gz) |
(1),(3) |
ztar |
compressed tar file (.tar.Z) |
(3) |
tar |
tar file (.tar) |
(3) |
zip |
zip file (.zip) |
(4) |
rpm |
RPM |
(5) |
pkgtool |
Solaris pkgtool |
|
sdux |
HP-UX swinstall |
|
rpm |
RPM |
(5) |
wininst |
self-extracting ZIP file for Windows |
(2),(4) |
Notes:
- (1)
- default on Unix
- (2)
- default on Windows ** to-do! **
- (3)
- requires external utilities: tar and possibly one of gzip, bzip2, or compress
- (4)
- requires either external zip utility or zipfile
module (part of the standard Python library since Python 1.6)
- (5)
- requires external rpm utility, version 3.0.4 or better (use
rpm
-
-
version to find out which version you have)
You don't have to use the bdist command with the --formats
option; you can also use the command that directly implements the format you're interested in.
Some of these bdist ``sub-commands'' actually generate several similar formats;
for instance, the bdist_dumb command generates all the ``dumb'' archive formats (tar,
ztar, gztar, and zip), and bdist_rpm
generates both binary and source RPMs. The bdist sub-commands, and the formats
generated by each, are:
bdist_dumb |
tar, ztar, gztar, zip |
bdist_rpm |
rpm, srpm |
bdist_wininst |
wininst |
The following sections give details on the individual bdist_* commands.
6.1 Creating dumb built distributions
** Need to document absolute vs. prefix-relative packages here, but first I have to
implement it! **
6.2 Creating RPM packages
The RPM format is used by many popular Linux distributions, including Red Hat, SuSE, and
Mandrake. If one of these (or any of the other RPM-based Linux distributions) is your usual
environment, creating RPM packages for other users of that same distribution is trivial.
Depending on the complexity of your module distribution and differences between Linux
distributions, you may also be able to create RPMs that work on different RPM-based
distributions.
The usual way to create an RPM of your module distribution is to run the bdist_rpm
command:
python setup.py bdist_rpm
or the bdist command with the --format option:
python setup.py bdist --formats=rpm
The former allows you to specify RPM-specific options; the latter allows you to easily
specify multiple formats in one run. If you need to do both, you can explicitly specify
multiple bdist_* commands and their options:
python setup.py bdist_rpm --packager="John Doe <jdoe@python.net>" \
bdist_wininst --target_version="2.0"
Creating RPM packages is driven by a .spec file, much as using
the Distutils is driven by the setup script. To make your life easier, the bdist_rpm
command normally creates a .spec file based on the information you
supply in the setup script, on the command line, and in any Distutils configuration files.
Various options and sections in the .spec file are derived from
options in the setup script as follows:
| Name |
name |
| Summary (in preamble) |
description |
| Version |
version |
| Vendor |
author and author_email,
or
& maintainer and maintainer_email |
| Copyright |
licence |
| Url |
url |
| %description (section) |
long_description |
Additionally, there many options in .spec files that don't have
corresponding options in the setup script. Most of these are handled through options to the bdist_rpm
command as follows:
| Release |
release |
``1'' |
| Group |
group |
``Development/Libraries'' |
| Vendor |
vendor |
(see above) |
| Packager |
packager |
(none) |
| Provides |
provides |
(none) |
| Requires |
requires |
(none) |
| Conflicts |
conflicts |
(none) |
| Obsoletes |
obsoletes |
(none) |
| Distribution |
distribution_name |
(none) |
| BuildRequires |
build_requires |
(none) |
| Icon |
icon |
(none) |
Obviously, supplying even a few of these options on the command-line would be tedious and
error-prone, so it's usually best to put them in the setup configuration file, setup.cfg--see section 4.
If you distribute or package many Python module distributions, you might want to put options
that apply to all of them in your personal Distutils configuration file (~/.pydistutils.cfg).
There are three steps to building a binary RPM package, all of which are handled
automatically by the Distutils:
- create a .spec file, which describes the package (analogous to
the Distutils setup script; in fact, much of the information in the setup script winds up
in the .spec file)
- create the source RPM
- create the ``binary'' RPM (which may or may not contain binary code, depending on
whether your module distribution contains Python extensions)
Normally, RPM bundles the last two steps together; when you use the Distutils, all three steps
are typically bundled together.
If you wish, you can separate these three steps. You can use the --spec-only
option to make bdist_rpm just create the .spec file and
exit; in this case, the .spec file will be written to the
``distribution directory''--normally dist/, but customizable with
the --dist-dir option. (Normally, the .spec
file winds up deep in the ``build tree,'' in a temporary directory created by bdist_rpm.)
** this isn't implemented yet--is it needed?! ** You can also specify a custom .spec file with the --spec-file option; used in
conjunction with --spec-only, this gives you an opportunity to
customize the .spec file manually:
> python setup.py bdist_rpm --spec-only
# ...edit dist/FooBar-1.0.spec
> python setup.py bdist_rpm --spec-file=dist/FooBar-1.0.spec
(Although a better way to do this is probably to override the standard bdist_rpm
command with one that writes whatever else you want to the .spec
file.)
6.3 Creating Windows Installers
Executable installers are the natural format for binary distributions on Windows. They
display a nice graphical user interface, display some information about the module
distribution to be installed taken from the metadata in the setup script, let the user select
a few options, and start or cancel the installation.
Since the metadata is taken from the setup script, creating Windows installers is usually
as easy as running:
python setup.py bdist_wininst
or the bdist command with the --formats option:
python setup.py bdist --formats=wininst
If you have a pure module distribution (only containing pure Python modules and packages),
the resulting installer will be version independent and have a name like foo-1.0.win32.exe.
These installers can even be created on Unix or
MacOS platforms.
If you have a non-pure distribution, the extensions can only be created on a Windows
platform, and will be Python version dependent. The installer filename will reflect this and
now has the form foo-1.0.win32-py2.0.exe. You have to create a
separate installer for every Python version you want to support.
The installer will try to compile pure modules into bytecode after installation on the
target system in normal and optimizing mode. If you don't want this to happen for some reason,
you can run the bdist_wininst command with the --no-target-compile
and/or the --no-target-optimize option.
By default the installer will display the cool ``Python Powered'' logo when it is run, but
you can also supply your own bitmap which must be a Windows .bmp
file with the --bitmap option.
The installer will also display a large title on the desktop background window when it is
run, which is constructed from the name of your distribution and the version number. This can
be changed to another text by using the --title option.
The installer file will be written to the ``distribution directory'' -- normally dist/, but customizable with the --dist-dir
option.
6.3.1 The Postinstallation script
Starting with Python 2.3, a postinstallation script can be specified which the --install-script option. The basename of the script must be specified,
and the script filename must also be listed in the scripts argument to the setup function.
This script will be run at installation time on the target system after all the files have
been copied, with argv[1] set to '-install', and again at uninstallation time before the files
are removed with argv[1] set to '-remove'.
The installation script runs embedded in the windows installer, every output (sys.stdout,
sys.stderr) is redirected into a buffer and will be displayed in the GUI after the script has
finished.
Some functions especially useful in this context are available in the installation script.
directory_created(pathname)
file_created(pathname)
These functions should be called when a directory or file is created by the postinstall
script at installation time. It will register the pathname with the uninstaller, so that it
will be removed when the distribution is uninstalled. To be safe, directories are only removed
if they are empty.
get_special_folder_path(csidl_string)
This function can be used to retrieve special folder locations on Windows like the Start
Menu or the Desktop. It returns the full path to the folder. 'csidl_string' must be one of the
following strings:
"CSIDL_APPDATA"
"CSIDL_COMMON_STARTMENU"
"CSIDL_STARTMENU"
"CSIDL_COMMON_DESKTOPDIRECTORY"
"CSIDL_DESKTOPDIRECTORY"
"CSIDL_COMMON_STARTUP"
"CSIDL_STARTUP"
"CSIDL_COMMON_PROGRAMS"
"CSIDL_PROGRAMS"
"CSIDL_FONTS"
If the folder cannot be retrieved, OSError is raised.
Which folders are available depends on the exact Windows version, and probably also the
configuration. For details refer to Microsoft's documentation of the SHGetSpecialFolderPath
function.
create_shortcut(target, description, filename[, arguments[,
workdir[, iconpath[, iconindex]]]])
This function creates a shortcut. target is the path to the program to be
started by the shortcut. description is the description of the sortcut. filename
is the title of the shortcut that the user will see. arguments specifies the
command line arguments, if any. workdir is the working directory for the program. iconpath
is the file containing the icon for the shortcut, and iconindex is the index of the
icon in the file iconpath. Again, for details consult the Microsoft documentation
for the IShellLink interface.
|
