* Documented the standard environment, including the generic builder.
This commit is contained in:
Eelco Dolstra
parent
2c3b29c5ca
commit
b8aaef5e4e
|
|
@ -1285,7 +1285,256 @@ character, or inline/multi-line, enclosed within <literal>/*
|
|||
|
||||
<sect1 id='sec-standard-environment'><title>The standard environment</title>
|
||||
|
||||
<para>TODO</para>
|
||||
<para>The standard build environment in the Nix Packages collection
|
||||
provides a basic environment for building Unix packages. It consists
|
||||
of the following components:
|
||||
|
||||
<itemizedlist>
|
||||
|
||||
<listitem><para>The GNU C Compiler, configured with C and C++
|
||||
support. On Linux, the compiler has been patched to provide greater
|
||||
<quote>purity</quote> assurance. For instance, the compiler doesn't
|
||||
search in locations such as <filename>/usr/include</filename>. In
|
||||
fact, attempts to add such directories through the
|
||||
<option>-I</option> flag are filtered out. Likewise, the linker
|
||||
(from GNU binutils) doesn't search in standard locations such as
|
||||
<filename>/usr/lib</filename>. Programs built on Linux are linked
|
||||
against a GNU C Library that likewise doesn't search in the default
|
||||
system locations.</para></listitem>
|
||||
|
||||
<listitem><para>GNU coreutils (contains a few dozen standard Unix
|
||||
commands).</para></listitem>
|
||||
|
||||
<listitem><para>GNU findutils (contains
|
||||
<command>find</command>).</para></listitem>
|
||||
|
||||
<listitem><para>GNU diffutils (contains <command>diff</command>,
|
||||
<command>cmp</command>).</para></listitem>
|
||||
|
||||
<listitem><para>GNU <command>sed</command>.</para></listitem>
|
||||
|
||||
<listitem><para>GNU <command>grep</command>.</para></listitem>
|
||||
|
||||
<listitem><para>GNU <command>awk</command>.</para></listitem>
|
||||
|
||||
<listitem><para>GNU <command>tar</command>.</para></listitem>
|
||||
|
||||
<listitem><para><command>gzip</command> and
|
||||
<command>bzip2</command>.</para></listitem>
|
||||
|
||||
<listitem><para>GNU Make. It has been patched to provide
|
||||
<quote>nested</quote> output that can be fed into the
|
||||
<command>log2xml</command> command and <command>log2html</command>
|
||||
stylesheet to create a structured, readable output of the build
|
||||
steps performed by Make.</para></listitem>
|
||||
|
||||
<listitem><para>Bash. This is the shell used for all builders in
|
||||
the Nix Packages collection. Not using <command>/bin/sh</command>
|
||||
removes a large source of portability problems.</para></listitem>
|
||||
|
||||
<listitem><para>Patch.</para></listitem>
|
||||
|
||||
</itemizedlist>
|
||||
|
||||
</para>
|
||||
|
||||
<para>The standard environment is used by passing it as an input
|
||||
called <envar>stdenv</envar> to the derivation, and then doing
|
||||
|
||||
<programlisting>
|
||||
. $stdenv/setup</programlisting>
|
||||
|
||||
at the top of the builder.</para>
|
||||
|
||||
<para>Apart from adding the aforementioned commands to the
|
||||
<envar>PATH</envar>, <filename>setup</filename> also does the
|
||||
following:
|
||||
|
||||
<itemizedlist>
|
||||
|
||||
<listitem><para>All input components specified in the
|
||||
<envar>buildInputs</envar> environment variable have their
|
||||
<filename>/bin</filename> subdirectory added to <envar>PATH</envar>,
|
||||
their <filename>/include</filename> subdirectory added to the C/C++
|
||||
header file search path, and their <filename>/lib</filename>
|
||||
subdirectory added to the linker search path. This can be extended.
|
||||
For instance, when the <command>pkgconfig</command> component is
|
||||
used, the subdirectory <filename>/lib/pkgconfig</filename> of each
|
||||
input is added to the <envar>PKG_CONFIG_PATH</envar> environment
|
||||
variable.</para></listitem>
|
||||
|
||||
<listitem><para>The environment variable
|
||||
<envar>NIX_CFLAGS_STRIP</envar> is set so that the compiler strips
|
||||
debug information from object files. This can be disabled by
|
||||
setting <envar>NIX_STRIP_DEBUG</envar> to
|
||||
<literal>0</literal>.</para></listitem>
|
||||
|
||||
</itemizedlist>
|
||||
|
||||
</para>
|
||||
|
||||
<para>The <filename>setup</filename> script also exports a function
|
||||
called <function>genericBuilder</function> that knows how to build
|
||||
typical Autoconf-style components. It can be customised to perform
|
||||
builds for any type of component. It is advisable to use
|
||||
<function>genericBuild</function> since it provides facilities that
|
||||
are almost always useful such as unpacking of sources, patching of
|
||||
sources, nested logging, etc.</para>
|
||||
|
||||
<para>The operation of the generic builder can be modified in many
|
||||
places by setting certain variables. These <emphasis>hook
|
||||
variables</emphasis> are typically set to the name of some shell
|
||||
function defined by you. For instance, to perform some additional
|
||||
steps after <command>make install</command> you would set the
|
||||
<varname>postInstall</varname> variable:
|
||||
|
||||
<programlisting>
|
||||
postInstall=myPostInstall
|
||||
|
||||
myPostInstall() {
|
||||
mkdir $out/share/extra
|
||||
cp extrafiles/* $out/share/extra
|
||||
}</programlisting>
|
||||
|
||||
</para>
|
||||
|
||||
<para>The generic builder has a number of <emphasis>phases</emphasis>,
|
||||
each of which can be override in its entirety by setting the indicated
|
||||
variable. The phases are:
|
||||
|
||||
<itemizedlist>
|
||||
|
||||
<listitem>
|
||||
|
||||
<para><function>unpackPhase</function>: unpacks the source files
|
||||
listed in the <envar>src</envar> environment variable to the
|
||||
current directory. It supports <filename>tar</filename> files,
|
||||
optionally compressed with <command>gzip</command> or
|
||||
<command>bzip2</command>; Zip files (but note that the
|
||||
<command>unzip</command> command is not a part of the standard
|
||||
environment; you should add it as a build input yourself); and
|
||||
unpacked source trees (i.e., directories; they are copied
|
||||
verbatim). You can add support for other file types by setting
|
||||
the <varname>findUnpacker</varname> hook. This hook should set an
|
||||
the variable <varname>unpackCmd</varname> to contain the command
|
||||
to be executed to unpack the file.</para>
|
||||
|
||||
<para>After unpacking all source files,
|
||||
<function>unpackPhase</function> changes the current directory to
|
||||
the directory created by unpacking the sources. If there are
|
||||
multiple source directories, you should set
|
||||
<varname>sourceRoot</varname> to the name of the intended
|
||||
directory.</para>
|
||||
|
||||
<para>It also calls the hook <varname>postUnpack</varname> after
|
||||
unpacking.</para>
|
||||
|
||||
</listitem>
|
||||
|
||||
<listitem><para><function>patchPhase</function> calls the
|
||||
<command>patch</command> command with the <option>-p1</option>
|
||||
option for each patch file listed in the <envar>patches</envar>
|
||||
variable.</para></listitem>
|
||||
|
||||
<listitem>
|
||||
|
||||
<para><function>configurePhase</function> runs the script called
|
||||
<filename>configure</filename> in the current directory with a
|
||||
<option>--prefix</option> set to the output path. You can add
|
||||
additional flag through the <varname>configureFlags</varname>
|
||||
variable. If <filename>configure</filename> does not exist,
|
||||
nothing happens.</para>
|
||||
|
||||
<para>Before and after running <filename>configure</filename>, the
|
||||
hooks <varname>preConfigure</varname> and
|
||||
<varname>postConfigure</varname> are called, respectively.</para>
|
||||
|
||||
</listitem>
|
||||
|
||||
<listitem>
|
||||
|
||||
<para><function>buildPhase</function> calls
|
||||
<command>make</command>. You can set flags for
|
||||
<command>make</command> through the <varname>makeFlags</varname>
|
||||
variable.</para>
|
||||
|
||||
<para>Before and after running <command>make</command>, the hooks
|
||||
<varname>preBuild</varname> and <varname>postBuild</varname> are
|
||||
called, respectively.</para>
|
||||
|
||||
</listitem>
|
||||
|
||||
<listitem><para><function>checkPhase</function> calls <command>make
|
||||
check</command>, but only if the <varname>doCheck</varname> variable
|
||||
is set to <literal>1</literal>. Additional flags can be set through
|
||||
the <varname>checkFlags</varname> variable.</para></listitem>
|
||||
|
||||
<listitem>
|
||||
|
||||
<para><function>installPhase</function> calls <command>make
|
||||
install</command>. Additional flags can be set through the
|
||||
<varname>installFlags</varname> variable. It also strips any
|
||||
static libraries in the output path of debug information unless
|
||||
<varname>dontStrip</varname> is set to
|
||||
<literal>1</literal>.</para>
|
||||
|
||||
<para>Before and after running <command>make install</command>,
|
||||
the hooks <varname>preInstall</varname> and
|
||||
<varname>postInstall</varname> are called, respectively.</para>
|
||||
|
||||
</listitem>
|
||||
|
||||
<listitem>
|
||||
|
||||
<para><function>distPhase</function> calls <command>make
|
||||
dist</command>, but only if the <varname>doDist</varname> variable
|
||||
is set to <literal>1</literal>. Additional flags can be set
|
||||
through the <varname>distFlags</varname> variable. The resulting
|
||||
tarball is copied to the <filename>/tarballs</filename>
|
||||
subdirectory of the output path.</para>
|
||||
|
||||
<para>Before and after running <command>make dist</command>, the
|
||||
hooks <varname>preDist</varname> and <varname>postDist</varname>
|
||||
are called, respectively.</para>
|
||||
|
||||
</listitem>
|
||||
|
||||
</itemizedlist>
|
||||
|
||||
</para>
|
||||
|
||||
<para>You can change the order in which phases are executed, or add
|
||||
new phases, by setting the <varname>phases</varname> variable. The
|
||||
default is <literal>patchPhase configurePhase buildPhase checkPhase
|
||||
installPhase distPhase</literal>.</para>
|
||||
|
||||
<para>At the beginning of each phase, the set of all shell variables
|
||||
is written to the file <filename>env-vars</filename> at the top-level
|
||||
build directory. This is useful for debugging: it allows you to
|
||||
recreate the environment in which a build was performed. For
|
||||
instance, if a build fails, then assuming you used the
|
||||
<option>-K</option> flag, you can go to the output directory and
|
||||
<quote>switch</quote> to the environment of the builder:
|
||||
|
||||
<screen>
|
||||
$ nix-build -K ./foo.nix
|
||||
... fails, keeping build directory `/tmp/nix-1234-0'
|
||||
|
||||
$ cd /tmp/nix-1234-0
|
||||
|
||||
$ source env-vars
|
||||
|
||||
<lineannotation>(edit some files...)</lineannotation>
|
||||
|
||||
$ make
|
||||
|
||||
<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen>
|
||||
|
||||
</para>
|
||||
|
||||
<para>The definitive, up-to-date documentation of the generic builder
|
||||
is the source itself, which resides in
|
||||
<filename>pkgs/stdenv/generic/setup.sh</filename>.</para>
|
||||
|
||||
</sect1>
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue