* More manual fixes.
This commit is contained in:
Eelco Dolstra
parent
0b79a12082
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9f8964a062
2 changed files with 35 additions and 38 deletions
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@ -14,10 +14,10 @@ build farm, since:
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instance, if you perform a build for a
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<literal>powerpc-darwin</literal> on an
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<literal>i686-linux</literal> machine, Nix can automatically forward
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to build to a <literal>powerpc-darwin</literal> machine, if
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the build to a <literal>powerpc-darwin</literal> machine, if
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available.</para></listitem>
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<listitem><para>The Nix expression language is ideal for providing
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<listitem><para>The Nix expression language is ideal for describing
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build jobs, plus all their dependencies. For instance, if your
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package has some dependency, you don't have to manually install it
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on all the machines in the build farm; they will be built
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@ -26,9 +26,9 @@ build farm, since:
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<listitem><para>Proper release management requires that builds (if
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deployed) are traceable: it should be possible to figure out from
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exactly what sources they were built, in what configuration, etc.;
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and it should be possible to reproduce the build, if necessary.
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Nix's hashing scheme uniquely identifies builds, and Nix expressions
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are self-contained.</para></listitem>
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and it should be possible to reproduce the build, if necessary. Nix
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makes this possible since Nix's hashing scheme uniquely identifies
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builds, and Nix expressions are self-contained.</para></listitem>
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<listitem><para>Nix will only rebuild things that have actually
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changed. For instance, if the sources of a component haven't
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@ -83,9 +83,7 @@ the single Nix expression in that directory
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would expect in a basic Unix environment: a C/C++ compiler (GCC,
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to be precise), the Bash shell, fundamental Unix tools such as
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<command>cp</command>, <command>grep</command>,
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<command>tar</command>, etc. (See
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<filename>pkgs/stdenv/nix/path.nix</filename> to see what's in
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<command>stdenv</command>.) <varname>fetchurl</varname> is a
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<command>tar</command>, etc. <varname>fetchurl</varname> is a
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function that downloads files. <varname>perl</varname> is the
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Perl interpreter.</para>
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@ -109,12 +107,12 @@ the single Nix expression in that directory
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<varname>mkDerivation</varname> is a function provided by
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<varname>stdenv</varname> that builds a component from a set of
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<emphasis>attributes</emphasis>. An attribute set is just a list
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of key/value pairs where the value is an arbitrary Nix expression.
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They take the general form
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of key/value pairs where each value is an arbitrary Nix
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expression. They take the general form
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<literal>{<replaceable>name1</replaceable> =
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<replaceable>expr1</replaceable>; <replaceable>...</replaceable>
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<replaceable>name1</replaceable> =
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<replaceable>expr1</replaceable>;</literal>.</para>
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<replaceable>nameN</replaceable> =
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<replaceable>exprN</replaceable>;}</literal>.</para>
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</callout>
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@ -148,11 +146,11 @@ the single Nix expression in that directory
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<para>The builder has to know what the sources of the component
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are. Here, the attribute <varname>src</varname> is bound to the
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result of a call to the <command>fetchurl</command> function.
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Given a URL and a MD5 hash of the expected contents of the file at
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that URL, this function actually builds a derivation that
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downloads the file and checks its hash. So the sources are a
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dependency that like all other dependencies is built before Hello
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itself is built.</para>
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Given a URL and an MD5 hash of the expected contents of the file
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at that URL, this function builds a derivation that downloads the
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file and checks its hash. So the sources are a dependency that
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like all other dependencies is built before Hello itself is
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built.</para>
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<para>Instead of <varname>src</varname> any other name could have
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been used, and in fact there can be any number of sources (bound
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@ -172,7 +170,7 @@ the single Nix expression in that directory
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<programlisting>
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perl = perl;</programlisting>
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will do the trink: it binds an attribute <varname>perl</varname>
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will do the trick: it binds an attribute <varname>perl</varname>
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to the function argument which also happens to be called
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<varname>perl</varname>. However, it looks a bit silly, so there
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is a shorter syntax. The <literal>inherit</literal> keyword
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@ -218,7 +216,8 @@ steps:</para>
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<callout arearefs='ex-hello-builder-co-1'>
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<para>When Nix runs a builder, it initially completely clears the
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environment. For instance, the <envar>PATH</envar> variable is
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environment (except for the attributes declared in the
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derivation). For instance, the <envar>PATH</envar> variable is
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empty<footnote><para>Actually, it's initialised to
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<filename>/path-not-set</filename> to prevent Bash from setting it
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to a default value.</para></footnote>. This is done to prevent
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@ -596,13 +595,11 @@ language. Purity means that operations in the language don't have
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side-effects (for instance, there is no variable assignment).
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Laziness means that arguments to functions are evaluated only when
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they are needed. Functional means that functions are
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<quote>normal</quote> values that can be passed around and
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manipulated in interesting ways.</para>
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<para>The language is not a full-featured, general purpose language.
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It's main job is to describe components, compositions of components,
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and the variability within components. For this a functional language
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is perfectly suited.</para>
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<quote>normal</quote> values that can be passed around and manipulated
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in interesting ways. The language is not a full-featured, general
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purpose language. It's main job is to describe components,
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compositions of components, and the variability within
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components.</para>
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<para>This section presents the various features of the
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language.</para>
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@ -773,7 +770,7 @@ and evaluates to <literal>"foobar"</literal>.
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<simplesect><title>Inheriting attributes</title>
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<para>When defining an attribute set itt is often convenient to copy
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<para>When defining an attribute set it is often convenient to copy
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variables from the surrounding lexical scope (e.g., when you want to
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propagate attributes). This can be shortened using the
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<literal>inherit</literal> keyword. For instance,
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@ -849,7 +846,7 @@ let {
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</para>
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<para>It is also possible to define a function that takes a single
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argument and that does need to be called with an attribute set as
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argument and that does not need to be called with an attribute set as
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argument. The syntax is
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<programlisting>
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@ -959,10 +956,10 @@ used in the Nix expression for Subversion.</para>
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<callout arearefs='ex-subversion-nix-co-2'>
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<para>This assertion says that in order for Subversion to have SSL
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support (so that it can access <literal>https</literal> URLs), an
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OpenSSL library must be passed. Additionally, it says
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OpenSSL library must be passed. Additionally, it says that
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<emphasis>if</emphasis> Apache support is enabled, then Apache's
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OpenSSL should much Subversion's. (Note that if Apache support is
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not enabled, we don't care about Apache's OpenSSL.)</para>
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OpenSSL should match Subversion's. (Note that if Apache support
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is not enabled, we don't care about Apache's OpenSSL.)</para>
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</callout>
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<callout arearefs='ex-subversion-nix-co-4'>
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@ -1241,14 +1238,14 @@ command-line argument. See <xref linkend='sec-standard-environment'
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written to <filename>/nix/var/log/nix</filename>.</para></listitem>
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<listitem><para>The builder is executed with the arguments specified
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by the attribute <varname>args</varname>. If it exit with exit code
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0, it is considered to have succeeded.</para></listitem>
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by the attribute <varname>args</varname>. If it exits with exit
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code 0, it is considered to have succeeded.</para></listitem>
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<listitem><para>The temporary directory is removed (unless the
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<option>-K</option> option was specified).</para></listitem>
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<listitem><para>If the build was succesful, Nix scans the output for
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references to the paths of the inputs. These so-called
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<listitem><para>If the build was successful, Nix scans the output
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for references to the paths of the inputs. These so-called
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<emphasis>retained dependencies</emphasis> could be used when the
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output of the derivation is used (e.g., when it's executed or used
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as input to another derivation), so if we deploy the derivation, we
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@ -1406,7 +1403,7 @@ variable. The phases are:
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<listitem>
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<para><function>unpackPhase</function>: unpacks the source files
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<para><function>unpackPhase</function> unpacks the source files
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listed in the <envar>src</envar> environment variable to the
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current directory. It supports <filename>tar</filename> files,
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optionally compressed with <command>gzip</command> or
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@ -1415,7 +1412,7 @@ variable. The phases are:
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environment; you should add it as a build input yourself); and
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unpacked source trees (i.e., directories; they are copied
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verbatim). You can add support for other file types by setting
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the <varname>findUnpacker</varname> hook. This hook should set an
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the <varname>findUnpacker</varname> hook. This hook should set
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the variable <varname>unpackCmd</varname> to contain the command
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to be executed to unpack the file.</para>
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@ -1441,7 +1438,7 @@ variable. The phases are:
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<para><function>configurePhase</function> runs the script called
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<filename>configure</filename> in the current directory with a
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<option>--prefix</option> set to the output path. You can add
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additional flag through the <varname>configureFlags</varname>
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additional flags through the <varname>configureFlags</varname>
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variable. If <filename>configure</filename> does not exist,
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nothing happens.</para>
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