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Diffstat (limited to 'doc/coding-conventions.xml')
-rw-r--r-- | doc/coding-conventions.xml | 53 |
1 files changed, 49 insertions, 4 deletions
diff --git a/doc/coding-conventions.xml b/doc/coding-conventions.xml index 61d373738f9..e1853d47ce0 100644 --- a/doc/coding-conventions.xml +++ b/doc/coding-conventions.xml @@ -169,8 +169,8 @@ stdenv.mkDerivation { ... args: with args; <replaceable>...</replaceable> </programlisting> - or - + or + <programlisting> { stdenv, fetchurl, perl, ... }: <replaceable>...</replaceable> </programlisting> @@ -598,6 +598,51 @@ evaluate correctly.</para> </section> </section> - - +<section xml:id="sec-sources"><title>Fetching Sources</title> + <para>There are multiple ways to fetch a package source in nixpkgs. The + general guidline is that you should package sources with a high degree of + availability. Right now there is only one fetcher which has mirroring + support and that is <literal>fetchurl</literal>. Note that you should also + prefer protocols which have a corresponding proxy environment variable. + </para> + <para>You can find many source fetch helpers in <literal>pkgs/build-support/fetch*</literal>. + </para> + <para>In the file <literal>pkgs/top-level/all-packages.nix</literal> you can + find fetch helpers, these have names on the form + <literal>fetchFrom*</literal>. The intention of these are to provide + snapshot fetches but using the same api as some of the version controlled + fetchers from <literal>pkgs/build-support/</literal>. As an example going + from bad to good: + <itemizedlist> + <listitem><para>Uses <literal>git://</literal> which won't be proxied. + <programlisting> + src = fetchgit { + url = "git://github.com/NixOS/nix.git"; + rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae"; + sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg"; + } + </programlisting></para> + </listitem> + <listitem><para>This is ok, but an archive fetch will still be faster. + <programlisting> + src = fetchgit { + url = "https://github.com/NixOS/nix.git"; + rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae"; + sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg"; + } + </programlisting></para> + </listitem> + <listitem><para>Fetches a snapshot archive and you get the rev you want. + <programlisting> + src = fetchFromGitHub { + owner = "NixOS"; + repo = "nix"; + rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae"; + sha256 = "04yri911rj9j19qqqn6m82266fl05pz98inasni0vxr1cf1gdgv9"; + } + </programlisting></para> + </listitem> + </itemizedlist> + </para> +</section> </chapter> |