Merge pull request #548 from tartley/master

Intro paras for Freezing and Packaging your code

docs/shipping/freezing.rst

@@ -1,19 +1,38 @@
+.. _freezing-your-code-ref:
+
+==================
 Freezing Your Code
 ==================
 
-An alternative to shipping your code is freezing it — shipping it as an
-executable with a bundled Python interpreter.
+To 'Freeze' your code is to distribute to end-users as an executable which
+includes a bundled Python interpreter.
 
-Many applications you use every day do this:
+Applications such as 'Dropbox', BitTorrent clients, 'Eve Online' and
+'Civilisation IV' do this.
 
-- Dropbox
-- BitTorrent
-- ...
+The advantage of distributing this way is that your application will work even
+if the user doesn't already have the required version of Python installed. On
+Windows, and even on many Linux distributions and OSX versions, the right
+version of Python will not already be installed.
+
+One disadvantage is that it will bloat your distribution by about 2MB.
+Another problem is that your application will not receive any security updates
+to the version of Python it uses unless you freeze a new version and get
+users to download it.
+
+Alternatives to Freezing
+------------------------
+
+:ref:`Packaging your code <packaging-your-code-ref>` is for distributing
+libraries or tools to other developers.
+
+On Linux, an alternative to freezing is to
+:ref:`create a Linux distro package <packaging-for-linux-distributions-ref>`
+(e.g. .deb files for Debian or Ubuntu, or .rpm files for Red Hat and SuSE.)
 
 .. todo:: Fill in "Freezing Your Code" stub
 
 
-
 Comparison
 ----------
 

docs/shipping/packaging.rst

@@ -1,13 +1,43 @@
+.. _packaging-your-code-ref:
+
+===================
 Packaging Your Code
 ===================
 
-Packaging your code is important.
+Package your code to share it with other developers. For example
+to share a library for other developers to use in their application,
+or for development tools like 'py.test'.
 
-You'll need to package your code first before sharing it with other developers.
+An advantage of this method of distribution is its well established ecosystem
+of tools such as PyPI and pip, which make it easy for other developers to
+download and install your package either for casual experiments, or as part of
+large, professional systems.
+
+It is a well-established convention for Python code to be shared this way.
+If your code isn't packaged on PyPI, then it will be harder
+for other developers to find it, and to use it as part of their existing
+process. They will regard such projects with substantial suspicion of being
+either badly managed or abandoned.
+
+The downside of distributing code like this is that it relies on the
+recipient understanding how to install the required version of Python,
+and being able and willing to use tools such as pip to install your code's
+other dependencies. This is fine when distributing to other developers, but
+makes this method unsuitable for distributing applications to end-uers.
 
 The `Python Packaging Guide <https://python-packaging-user-guide.readthedocs.org/en/latest/>`_
 provides an extensive guide on creating and maintaining Python packages.
 
+Alternatives to Packaging
+:::::::::::::::::::::::::
+
+To distribute applications to end-users, you should
+:ref:`freeze your application <freezing-your-code-ref>`.
+
+On Linux, you may also want to consider
+:ref:`creating a Linux distro package <packaging-for-linux-distributions-ref>`
+(e.g. a .deb file for Debian or Ubuntu.)
+
 For Python Developers
 :::::::::::::::::::::
 
@@ -106,9 +136,45 @@ prerequisite for this is that you have an Amazon AWS account with an S3 bucket.
 
 * You can now install your package with :code:`pip install --index-url=http://your-s3-bucket/packages/simple/ YourPackage`
 
+.. _packaging-for-linux-distributions-ref:
+
 For Linux Distributions
 ::::::::::::::::::::::::
 
+Creating a Linux distro package is arguably the "right way" to distribute code
+on Linux.
+
+Because a distribution package doesn't include the Python interpreter, it
+makes the download and install about 2MB smaller than
+:ref:`freezing your application <freezing-your-code-ref>`.
+
+Also, if a distribution releases a new security update for Python, then your
+application will automatically start using that new version of Python.
+
+The bdist_rpm command makes `producing an RPM file <https://docs.python.org/3/distutils/builtdist.html#creating-rpm-packages>`_
+for use by distributions like Red Hat or SuSE is trivially easy.
+
+However, creating and maintaining the different configurations required for
+each distribution's format (e.g. .deb for Debian/Ubuntu, .rpm for Red
+Hat/Fedora, etc) is a fair amount of work. If your code is an application that
+you plan to distribute on other platforms, then you'll also have to create and
+maintain the separate config required to freeze your application for Windows
+and OSX. It would be much less work to simply create and maintain a single
+config for one of the cross platform :ref:`freezing tools
+<freezing-your-code-ref>`, which will produce stand-alone executables for all
+distributions of Linux, as well as Windows and OSX.
+
+Creating a distribution package is also problematic if your code is for a
+version of Python that isn't currently supported by a distribution.
+Having to tell *some versions* of Ubuntu end-users that they need to add `the
+'dead-snakes' PPA <https://launchpad.net/~fkrull/+archive/ubuntu/deadsnakes>`_
+using `sudo apt-repository` commands before they can install your .deb file
+makes for an extremely hostile user experience. Not only that, but you'd have
+to maintain a custom equivalent of these instructions for every distribution,
+and worse, have your users read, understand, and act on them.
+
+Having said all that, here's how to do it:
+
 * `Fedora <https://fedoraproject.org/wiki/Packaging:Python>`_
 * `Debian and Ubuntu <http://www.debian.org/doc/packaging-manuals/python-policy/>`_
 * `Arch <https://wiki.archlinux.org/index.php/Python_Package_Guidelines>`_