nixpkgs/doc/quick-start.xml
Eelco Dolstra fd83f192d4 * Fixed some links.
svn path=/nixpkgs/trunk/; revision=16865
2009-08-26 16:52:02 +00:00

239 lines
9.5 KiB
XML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xml:id="chap-overvie">
<title>Quick Start to Adding a Package</title>
<para>To add a package to Nixpkgs:
<orderedlist>
<listitem>
<para>Checkout the Nixpkgs source tree:
<screen>
$ svn checkout https://svn.nixos.org/repos/nix/nixpkgs/trunk nixpkgs
$ cd nixpkgs</screen>
</para>
</listitem>
<listitem>
<para>Find a good place in the Nixpkgs tree to add the Nix
expression for your package. For instance, a library package
typically goes into
<filename>pkgs/development/libraries/<replaceable>pkgname</replaceable></filename>,
while a web browser goes into
<filename>pkgs/applications/networking/browsers/<replaceable>pkgname</replaceable></filename>.
See Section XXX for some hints on the tree organisation. Create a
directory for your package, e.g.
<screen>
$ svn mkdir pkgs/development/libraries/libfoo</screen>
</para>
</listitem>
<listitem>
<para>In the package directory, create a Nix expression — a piece
of code that describes how to build the package. In this case, it
should be a <emphasis>function</emphasis> that is called with the
package dependencies as arguments, and returns a build of the
package in the Nix store. The expression should usually be called
<filename>default.nix</filename>.
<screen>
$ emacs pkgs/development/libraries/libfoo/default.nix
$ svn add pkgs/development/libraries/libfoo/default.nix</screen>
</para>
<para>You can have a look at the existing Nix expressions under
<filename>pkgs/</filename> to see how its done. Here are some
good ones:
<itemizedlist>
<listitem>
<para>GNU cpio: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/tools/archivers/cpio/default.nix"><filename>pkgs/tools/archivers/cpio/default.nix</filename></link>.
The simplest possible package. The generic builder in
<varname>stdenv</varname> does everything for you. It has
no dependencies beyond <varname>stdenv</varname>.</para>
</listitem>
<listitem>
<para>GNU Hello: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/applications/misc/hello/ex-2/default.nix"><filename>pkgs/applications/misc/hello/ex-2/default.nix</filename></link>.
Also trivial, but it specifies some <varname>meta</varname>
attributes which is good practice.</para>
</listitem>
<listitem>
<para>GNU Multiple Precision arithmetic library (GMP): <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/development/libraries/gmp/default.nix"><filename>pkgs/development/libraries/gmp/default.nix</filename></link>.
Also done by the generic builder, but has a dependency on
<varname>m4</varname>.</para>
</listitem>
<listitem>
<para>Pan, a GTK-based newsreader: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/applications/networking/newsreaders/pan/default.nix"><filename>pkgs/applications/networking/newsreaders/pan/default.nix</filename></link>.
Has an optional dependency on <varname>gtkspell</varname>,
which is only built if <varname>spellCheck</varname> is
<literal>true</literal>.</para>
</listitem>
<listitem>
<para>Apache HTTPD: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/servers/http/apache-httpd/default.nix"><filename>pkgs/servers/http/apache-httpd/default.nix</filename></link>.
A bunch of optional features, variable substitutions in the
configure flags, a post-install hook, and miscellaneous
hackery.</para>
</listitem>
<listitem>
<para>BitTorrent (wxPython-based): <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/tools/networking/p2p/bittorrent/default.nix"><filename>pkgs/tools/networking/p2p/bittorrent/default.nix</filename></link>.
Uses an external <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/tools/networking/p2p/bittorrent/builder.sh">build
script</link>, which can be useful if you have lots of code
that you dont want cluttering up the Nix expression. But
external builders are mostly obsolete.
</para>
</listitem>
<listitem>
<para>Thunderbird: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/applications/networking/mailreaders/thunderbird-2.x/default.nix"><filename>pkgs/applications/networking/mailreaders/thunderbird-2.x/default.nix</filename></link>.
Lots of dependencies.</para>
</listitem>
<listitem>
<para>JDiskReport, a Java utility: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/tools/misc/jdiskreport/default.nix"><filename>pkgs/tools/misc/jdiskreport/default.nix</filename></link>
(and the <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/tools/misc/jdiskreport/builder.sh">builder</link>).
Nixpkgs doesnt have a decent <varname>stdenv</varname> for
Java yet so this is pretty ad-hoc.</para>
</listitem>
<listitem>
<para>XML::Simple, a Perl module: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/top-level/perl-packages.nix"><filename>pkgs/top-level/perl-packages.nix</filename></link>
(search for the <varname>XMLSimple</varname> attribute).
Most Perl modules are so simple to build that they are
defined directly in <filename>perl-packages.nix</filename>;
no need to make a separate file for them.</para>
</listitem>
<listitem>
<para>Adobe Reader: <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/applications/misc/adobe-reader/default.nix"><filename>pkgs/applications/misc/adobe-reader/default.nix</filename></link>.
Shows how binary-only packages can be supported. In
particular the <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/applications/misc/adobe-reader/builder.sh">builder</link>
uses <command>patchelf</command> to set the RUNPATH and ELF
interpreter of the executables so that the right libraries
are found at runtime.</para>
</listitem>
</itemizedlist>
</para>
<para>Some notes:
<itemizedlist>
<listitem>
<para>All <varname>meta</varname> attributes are optional,
but its still a good idea to provide at least the
<varname>description</varname> and
<varname>homepage</varname>.</para>
</listitem>
<listitem>
<para>You can use <command>nix-prefetch-url</command>
<replaceable>url</replaceable> to get the SHA-256 hash of
source distributions.</para>
</listitem>
<listitem>
<para>A list of schemes for <literal>mirror://</literal>
URLs can be found in <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/build-support/fetchurl/mirrors.nix"><filename>pkgs/build-support/fetchurl/mirrors.nix</filename></link>.</para>
</listitem>
</itemizedlist>
</para>
<para>The exact syntax and semantics of the Nix expression
language, including the built-in function, are described in the
Nix manual in the <link
xlink:href="http://nixos.org/releases/nix/unstable/manual/#chap-writing-nix-expressions">chapter
on writing Nix expressions</link>.</para>
</listitem>
<listitem>
<para>Add a call to the function defined in the previous step to
<link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/top-level/all-packages.nix"><filename>pkgs/top-level/all-packages.nix</filename></link>
with some descriptive name for the variable,
e.g. <varname>libfoo</varname>.
<screen>
$ emacs pkgs/top-level/all-packages.nix</screen>
</para>
<para>The attributes in that file are sorted by category (like
“Development / Libraries”) that more-or-less correspond to the
directory structure of Nixpkgs, and then by attribute name.</para>
</listitem>
<listitem>
<para>Test whether the package builds:
<screen>
$ nix-build -A libfoo</screen>
where <varname>libfoo</varname> should be the variable name
defined in the previous step. You may want to add the flag
<option>-K</option> to keep the temporary build directory in case
something fails. If the build succeeds, a symlink
<filename>./result</filename> to the package in the Nix store is
created.</para>
</listitem>
<listitem>
<para>If you want to install the package into your profile
(optional), do
<screen>
$ nix-env -f . -iA libfoo</screen>
</para>
</listitem>
<listitem>
<para>Optionally commit the new package (<command>svn
ci</command>) or send a patch to
<literal>nix-dev@cs.uu.nl</literal>.</para>
</listitem>
<listitem>
<para>If you want the TU Delft build farm to build binaries of the
package and make them available in the <link
xlink:href="http://nixos.org/releases/nixpkgs/channels/nixpkgs-unstable/"><literal>nixpkgs</literal>
channel</link>, add it to <link
xlink:href="https://svn.nixos.org/repos/nix/nixpkgs/trunk/pkgs/top-level/build-for-release.nix"><filename>pkgs/top-level/build-for-release.nix</filename></link>.</para>
</listitem>
</orderedlist>
</para>
</chapter>