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Fleshed out the section on the setup config file, setup.cfg. 

Added a few clarifying footnotes and cross-references.
Various minor tweaks.
This commit is contained in:
Greg Ward 2000-09-04 20:07:15 +00:00
parent 5e08a01a98
commit 47f99a6174
1 changed files with 137 additions and 24 deletions
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Doc/dist/dist.tex vendored
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@ -78,7 +78,13 @@ without having to run a single setup script or compile a line of code.
\label{simple-example}
The setup script is usually quite simple, although since it's written in
Python, there are no arbitrary limits to what you can do with it. If
Python, there are no arbitrary limits to what you can do with
it.\footnote{But be careful about putting arbitrarily expensive
operations in your setup script; unlike, say, Autoconf-style configure
scripts, the setup script may be run multiple times in the course of
building and installing your module distribution. If you need to
insert potentially expensive processing steps into the Distutils
chain, see section~\ref{extending} on extending the Distutils.} If
all you want to do is distribute a module called \module{foo}, contained
in a file \file{foo.py}, then your setup script can be as little as
this:
@ -100,6 +106,7 @@ Some observations:
hold true for packages and extensions)
\item it's recommended that you supply a little more meta-data, in
particular your name, email address and a URL for the project
(see section~\ref{setup-script} for an example)
\end{itemize}
To create a source distribution for this module, you would create a
@ -153,7 +160,7 @@ medium-sized module collections. You'll need to have version XXX of
Wise installed on your system for the \command{bdist\_wise} command to
work; it's available from \url{http://foo/bar/baz}.)
Currently (Distutils 0.9.1), the are only other useful built
Currently (Distutils 0.9.2), the are only other useful built
distribution format is RPM, implemented by the \command{bdist\_rpm}
command. For example, the following command will create an RPM file
called \file{Foo-1.0.noarch.rpm}:
@ -552,24 +559,125 @@ intend to distribute your code.)
\label{setup-config}
Often, it's not possible to write down everything needed to build a
distribution \emph{a priori}. You need to get some information from the
user, or from the user's system, in order to proceed. For example, you
might include an optional extension module that provides an interface to
a particular C library. If that library is installed on the user's
system, then you can build your optional extension---but you need to
know where to find the header and library file. If it's not installed,
you need to know this so you can omit your optional extension.
distribution \emph{a priori}: you may need to get some information from
the user, or from the user's system, in order to proceed. As long as
that information is fairly simple---a list of directories to search for
C header files or libraries, for example---then providing a
configuration file, \file{setup.cfg}, for users to edit is a cheap and
easy way to solicit it. Configuration files also let you provide
default values for any command option, which the installer can then
override either on the command-line or by editing the config file.
The preferred way to do this, of course, would be for you to tell the
Distutils which optional features (C libraries, system calls, external
utilities, etc.) you're looking for, and it would inspect the user's
system and try to find them. This functionality may appear in a future
version of the Distutils, but it isn't there now. So, for the time
being, we rely on the user building and installing your software to
provide the necessary information. The vehicle for doing so is the
setup configuration file, \file{setup.cfg}.
(If you have more advanced needs, such as determining which extensions
to build based on what capabilities are present on the target system,
then you need the Distutils ``auto-configuration'' facility. This
started to appear in Distutils 0.9 but, as of this writing, isn't mature
or stable enough yet for real-world use.)
\XXX{need more here!}
\XXX{should reference description of distutils config files in
``Installing'' manual here}
The setup configuration file is a useful middle-ground between the setup
script---which, ideally, would be opaque to installers\footnote{This
ideal probably won't be achieved until auto-configuration is fully
supported by the Distutils.}---and the command-line to the setup
script, which is outside of your control and entirely up to the
installer. In fact, \file{setup.cfg} (and any other Distutils
configuration files present on the target system) are processed after
the contents of the setup script, but before the command-line. This has
several useful consequences:
\begin{itemize}
\item installers can override some of what you put in \file{setup.py} by
editing \file{setup.cfg}
\item you can provide non-standard defaults for options that are not
easily set in \file{setup.py}
\item installers can override anything in \file{setup.cfg} using the
command-line options to \file{setup.py}
\end{itemize}
The basic syntax of the configuration file is simple:
\begin{verbatim}
[command]
option=value
...
\end{verbatim}
where \var{command} is one of the Distutils commands (e.g.
\command{build\_py}, \command{install}), and \var{option} is one of the
options that command supports. Any number of options can be supplied
for each command, and any number of command sections can be included in
the file. Blank lines are ignored, as are comments (from a \verb+#+
character to end-of-line). Long option values can be split across
multiple lines simply by indenting the continuation lines.
You can find out the list of options supported by a particular command
with the universal \longprogramopt{help} option, e.g.
\begin{verbatim}
> python setup.py --help build_ext
[...]
Options for 'build_ext' command:
--build-lib (-b) directory for compiled extension modules
--build-temp (-t) directory for temporary files (build by-products)
--inplace (-i) ignore build-lib and put compiled extensions into the
source directory alongside your pure Python modules
--include-dirs (-I) list of directories to search for header files
--define (-D) C preprocessor macros to define
--undef (-U) C preprocessor macros to undefine
[...]
\end{verbatim}
Or consult section \ref{reference} of this document (the command
reference).
Note that an option spelled \longprogramopt{foo-bar} on the command-line
is spelled \option{foo\_bar} in configuration files.
For example, say you want your extensions to be built
``in-place''---that is, you have an extension \module{pkg.ext}, and you
want the compiled extension file (\file{ext.so} on Unix, say) to be put
in the same source directory as your pure Python modules
\module{pkg.mod1} and \module{pkg.mod2}. You can always use the
\longprogramopt{inplace} option on the command-line to ensure this:
\begin{verbatim}
python setup.py build_ext --inplace
\end{verbatim}
But this requires that you always specify the \command{build\_ext}
command explicitly, and remember to provide \longprogramopt{inplace}.
An easier way is to ``set and forget'' this option, by encoding it in
\file{setup.cfg}, the configuration file for this distribution:
\begin{verbatim}
[build_ext]
inplace=1
\end{verbatim}
This will affect all builds of this module distribution, whether or not
you explcitly specify \command{build\_ext}. If you include
\file{setup.cfg} in your source distribution, it will also affect
end-user builds---which is probably a bad idea for this option, since
always building extensions in-place would break installation of the
module distribution. In certain peculiar cases, though, modules are
built right in their installation directory, so this is conceivably a
useful ability. (Distributing extensions that expect to be built in
their installation directory is almost always a bad idea, though.)
Another example: certain commands take a lot of options that don't
change from run-to-run; for example, \command{bdist\_rpm} needs to know
everything required to generate a ``spec'' file for creating an RPM
distribution. Some of this information comes from the setup script, and
some is automatically generated by the Distutils (such as the list of
files installed). But some of it has to be supplied as options to
\command{bdist\_rpm}, which would be very tedious to do on the
command-line for every run. Hence, here is a snippet from the
Distutils' own \file{setup.cfg}:
\begin{verbatim}
[bdist_rpm]
release = 1
packager = Greg Ward <gward@python.net>
doc_files = CHANGES.txt
README.txt
USAGE.txt
doc/
examples/
\end{verbatim}
Note that the \option{doc\_files} option is simply a
whitespace-separated string split across multiple lines for readability.
\section{Creating a Source Distribution}
@ -597,16 +705,21 @@ python setup.py sdist --formats=gztar,zip
to create a gzipped tarball and a zip file. The available formats are:
\begin{tableiii}{l|l|c}{code}%
{Format}{Description}{Notes}
\lineiii{zip}{zip file (\file{.zip})}{(1)}
\lineiii{gztar}{gzipped tar file (\file{.tar.gz})}{(2)}
\lineiii{ztar}{compressed tar file (\file{.tar.Z})}{}
\lineiii{zip}{zip file (\file{.zip})}{(1),(2)}
\lineiii{gztar}{gzip'ed tar file (\file{.tar.gz})}{(3),(4)}
\lineiii{bztar}{bzip2'ed tar file (\file{.tar.gz})}{(4)}
\lineiii{ztar}{compressed tar file (\file{.tar.Z})}{(4)}
\lineiii{tar}{tar file (\file{.tar})}{}
\end{tableiii}
\noindent Notes:
\begin{description}
\item[(1)] default on Windows
\item[(2)] default on Unix
\item[(2)] under both Unix and Windows, requires either external
Info-ZIP utility \emph{or} the \module{zipfile} module
\item[(3)] default on Unix
\item[(4)] requires external utilities: \program{tar} and possibly one
of \program{gzip}, \program{bzip2}, or \program{compress}
\end{description}
@ -659,7 +772,7 @@ list of files. This list is written to the manifest for future
reference, and then used to build the source distribution archive(s).
Following the Distutils' own manifest template, let's trace how the
\command{sdist} command will build the list of files to include in the
\command{sdist} command builds the list of files to include in the
Distutils source distribution:
\begin{enumerate}
\item include all Python source files in the \file{distutils} and
@ -869,7 +982,7 @@ each, are:
\section{Reference}
\label{ref}
\label{reference}
\subsection{Building modules: the \protect\command{build} command family}