1233 lines
		
	
	
	
		
			48 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
			
		
		
	
	
			1233 lines
		
	
	
	
		
			48 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
| <?xml version="1.0" encoding="utf-8"?>
 | ||
| <refentry xmlns="http://docbook.org/ns/docbook"
 | ||
|           xmlns:xlink="http://www.w3.org/1999/xlink"
 | ||
|           xmlns:xi="http://www.w3.org/2001/XInclude"
 | ||
|           xml:id="sec-conf-file"
 | ||
|           version="5">
 | ||
| 
 | ||
| <refmeta>
 | ||
|   <refentrytitle>nix.conf</refentrytitle>
 | ||
|   <manvolnum>5</manvolnum>
 | ||
|   <refmiscinfo class="source">Nix</refmiscinfo>
 | ||
|   <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 | ||
| </refmeta>
 | ||
| 
 | ||
| <refnamediv>
 | ||
|   <refname>nix.conf</refname>
 | ||
|   <refpurpose>Nix configuration file</refpurpose>
 | ||
| </refnamediv>
 | ||
| 
 | ||
| <refsection><title>Description</title>
 | ||
| 
 | ||
| <para>Nix reads settings from two configuration files:</para>
 | ||
| 
 | ||
| <itemizedlist>
 | ||
| 
 | ||
|   <listitem>
 | ||
|     <para>The system-wide configuration file
 | ||
|     <filename><replaceable>sysconfdir</replaceable>/nix/nix.conf</filename>
 | ||
|     (i.e. <filename>/etc/nix/nix.conf</filename> on most systems), or
 | ||
|     <filename>$NIX_CONF_DIR/nix.conf</filename> if
 | ||
|     <envar>NIX_CONF_DIR</envar> is set.</para>
 | ||
|   </listitem>
 | ||
| 
 | ||
|   <listitem>
 | ||
|     <para>The user configuration file
 | ||
|     <filename>$XDG_CONFIG_HOME/nix/nix.conf</filename>, or
 | ||
|     <filename>~/.config/nix/nix.conf</filename> if
 | ||
|     <envar>XDG_CONFIG_HOME</envar> is not set.</para>
 | ||
|   </listitem>
 | ||
| 
 | ||
| </itemizedlist>
 | ||
| 
 | ||
| <para>The configuration files consist of
 | ||
| <literal><replaceable>name</replaceable> =
 | ||
| <replaceable>value</replaceable></literal> pairs, one per line. Other
 | ||
| files can be included with a line like <literal>include
 | ||
| <replaceable>path</replaceable></literal>, where
 | ||
| <replaceable>path</replaceable> is interpreted relative to the current
 | ||
| conf file and a missing file is an error unless
 | ||
| <literal>!include</literal> is used instead.
 | ||
| Comments start with a <literal>#</literal> character.  Here is an
 | ||
| example configuration file:</para>
 | ||
| 
 | ||
| <programlisting>
 | ||
| keep-outputs = true       # Nice for developers
 | ||
| keep-derivations = true   # Idem
 | ||
| </programlisting>
 | ||
| 
 | ||
| <para>You can override settings on the command line using the
 | ||
| <option>--option</option> flag, e.g. <literal>--option keep-outputs
 | ||
| false</literal>.</para>
 | ||
| 
 | ||
| <para>The following settings are currently available:
 | ||
| 
 | ||
| <variablelist>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-allowed-uris"><term><literal>allowed-uris</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>A list of URI prefixes to which access is allowed in
 | ||
|       restricted evaluation mode. For example, when set to
 | ||
|       <literal>https://github.com/NixOS</literal>, builtin functions
 | ||
|       such as <function>fetchGit</function> are allowed to access
 | ||
|       <literal>https://github.com/NixOS/patchelf.git</literal>.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-allow-import-from-derivation"><term><literal>allow-import-from-derivation</literal></term>
 | ||
| 
 | ||
|     <listitem><para>By default, Nix allows you to <function>import</function> from a derivation,
 | ||
|     allowing building at evaluation time. With this option set to false, Nix will throw an error
 | ||
|     when evaluating an expression that uses this feature, allowing users to ensure their evaluation
 | ||
|     will not require any builds to take place.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-allow-new-privileges"><term><literal>allow-new-privileges</literal></term>
 | ||
| 
 | ||
|     <listitem><para>(Linux-specific.) By default, builders on Linux
 | ||
|     cannot acquire new privileges by calling setuid/setgid programs or
 | ||
|     programs that have file capabilities. For example, programs such
 | ||
|     as <command>sudo</command> or <command>ping</command> will
 | ||
|     fail. (Note that in sandbox builds, no such programs are available
 | ||
|     unless you bind-mount them into the sandbox via the
 | ||
|     <option>sandbox-paths</option> option.) You can allow the
 | ||
|     use of such programs by enabling this option. This is impure and
 | ||
|     usually undesirable, but may be useful in certain scenarios
 | ||
|     (e.g. to spin up containers or set up userspace network interfaces
 | ||
|     in tests).</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-allowed-users"><term><literal>allowed-users</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>A list of names of users (separated by whitespace) that
 | ||
|       are allowed to connect to the Nix daemon. As with the
 | ||
|       <option>trusted-users</option> option, you can specify groups by
 | ||
|       prefixing them with <literal>@</literal>. Also, you can allow
 | ||
|       all users by specifying <literal>*</literal>. The default is
 | ||
|       <literal>*</literal>.</para>
 | ||
| 
 | ||
|       <para>Note that trusted users are always allowed to connect.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-auto-optimise-store"><term><literal>auto-optimise-store</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal>, Nix
 | ||
|     automatically detects files in the store that have identical
 | ||
|     contents, and replaces them with hard links to a single copy.
 | ||
|     This saves disk space.  If set to <literal>false</literal> (the
 | ||
|     default), you can still run <command>nix-store
 | ||
|     --optimise</command> to get rid of duplicate
 | ||
|     files.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-builders">
 | ||
|     <term><literal>builders</literal></term>
 | ||
|     <listitem>
 | ||
|       <para>A list of machines on which to perform builds. <phrase
 | ||
|       condition="manual">See <xref linkend="chap-distributed-builds"
 | ||
|       /> for details.</phrase></para>
 | ||
|     </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-builders-use-substitutes"><term><literal>builders-use-substitutes</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal>, Nix will instruct
 | ||
|     remote build machines to use their own binary substitutes if available. In
 | ||
|     practical terms, this means that remote hosts will fetch as many build
 | ||
|     dependencies as possible from their own substitutes (e.g, from
 | ||
|     <literal>cache.nixos.org</literal>), instead of waiting for this host to
 | ||
|     upload them all. This can drastically reduce build times if the network
 | ||
|     connection between this computer and the remote build host is slow. Defaults
 | ||
|     to <literal>false</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-users-group"><term><literal>build-users-group</literal></term>
 | ||
| 
 | ||
|     <listitem><para>This options specifies the Unix group containing
 | ||
|     the Nix build user accounts.  In multi-user Nix installations,
 | ||
|     builds should not be performed by the Nix account since that would
 | ||
|     allow users to arbitrarily modify the Nix store and database by
 | ||
|     supplying specially crafted builders; and they cannot be performed
 | ||
|     by the calling user since that would allow him/her to influence
 | ||
|     the build result.</para>
 | ||
| 
 | ||
|     <para>Therefore, if this option is non-empty and specifies a valid
 | ||
|     group, builds will be performed under the user accounts that are a
 | ||
|     member of the group specified here (as listed in
 | ||
|     <filename>/etc/group</filename>).  Those user accounts should not
 | ||
|     be used for any other purpose!</para>
 | ||
| 
 | ||
|     <para>Nix will never run two builds under the same user account at
 | ||
|     the same time.  This is to prevent an obvious security hole: a
 | ||
|     malicious user writing a Nix expression that modifies the build
 | ||
|     result of a legitimate Nix expression being built by another user.
 | ||
|     Therefore it is good to have as many Nix build user accounts as
 | ||
|     you can spare.  (Remember: uids are cheap.)</para>
 | ||
| 
 | ||
|     <para>The build users should have permission to create files in
 | ||
|     the Nix store, but not delete them.  Therefore,
 | ||
|     <filename>/nix/store</filename> should be owned by the Nix
 | ||
|     account, its group should be the group specified here, and its
 | ||
|     mode should be <literal>1775</literal>.</para>
 | ||
| 
 | ||
|     <para>If the build users group is empty, builds will be performed
 | ||
|     under the uid of the Nix process (that is, the uid of the caller
 | ||
|     if <envar>NIX_REMOTE</envar> is empty, the uid under which the Nix
 | ||
|     daemon runs if <envar>NIX_REMOTE</envar> is
 | ||
|     <literal>daemon</literal>).  Obviously, this should not be used in
 | ||
|     multi-user settings with untrusted users.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-compress-build-log"><term><literal>compress-build-log</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal> (the default),
 | ||
|     build logs written to <filename>/nix/var/log/nix/drvs</filename>
 | ||
|     will be compressed on the fly using bzip2.  Otherwise, they will
 | ||
|     not be compressed.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-connect-timeout"><term><literal>connect-timeout</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>The timeout (in seconds) for establishing connections in
 | ||
|       the binary cache substituter.  It corresponds to
 | ||
|       <command>curl</command>’s <option>--connect-timeout</option>
 | ||
|       option.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-cores"><term><literal>cores</literal></term>
 | ||
| 
 | ||
|     <listitem><para>Sets the value of the
 | ||
|     <envar>NIX_BUILD_CORES</envar> environment variable in the
 | ||
|     invocation of builders.  Builders can use this variable at their
 | ||
|     discretion to control the maximum amount of parallelism.  For
 | ||
|     instance, in Nixpkgs, if the derivation attribute
 | ||
|     <varname>enableParallelBuilding</varname> is set to
 | ||
|     <literal>true</literal>, the builder passes the
 | ||
|     <option>-j<replaceable>N</replaceable></option> flag to GNU Make.
 | ||
|     It can be overridden using the <option
 | ||
|     linkend='opt-cores'>--cores</option> command line switch and
 | ||
|     defaults to <literal>1</literal>.  The value <literal>0</literal>
 | ||
|     means that the builder should use all available CPU cores in the
 | ||
|     system.</para>
 | ||
| 
 | ||
|     <para>See also <xref linkend="chap-tuning-cores-and-jobs" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-diff-hook"><term><literal>diff-hook</literal></term>
 | ||
|   <listitem>
 | ||
|     <para>
 | ||
|       Absolute path to an executable capable of diffing build results.
 | ||
|       The hook executes if <xref linkend="conf-run-diff-hook" /> is
 | ||
|       true, and the output of a build is known to not be the same.
 | ||
|       This program is not executed to determine if two results are the
 | ||
|       same.
 | ||
|     </para>
 | ||
| 
 | ||
|     <para>
 | ||
|       The diff hook is executed by the same user and group who ran the
 | ||
|       build. However, the diff hook does not have write access to the
 | ||
|       store path just built.
 | ||
|     </para>
 | ||
| 
 | ||
|     <para>The diff hook program receives three parameters:</para>
 | ||
| 
 | ||
|     <orderedlist>
 | ||
|       <listitem>
 | ||
|         <para>
 | ||
|           A path to the previous build's results
 | ||
|         </para>
 | ||
|       </listitem>
 | ||
| 
 | ||
|       <listitem>
 | ||
|         <para>
 | ||
|           A path to the current build's results
 | ||
|         </para>
 | ||
|       </listitem>
 | ||
| 
 | ||
|       <listitem>
 | ||
|         <para>
 | ||
|           The path to the build's derivation
 | ||
|         </para>
 | ||
|       </listitem>
 | ||
| 
 | ||
|       <listitem>
 | ||
|         <para>
 | ||
|           The path to the build's scratch directory. This directory
 | ||
|           will exist only if the build was run with
 | ||
|           <option>--keep-failed</option>.
 | ||
|         </para>
 | ||
|       </listitem>
 | ||
|     </orderedlist>
 | ||
| 
 | ||
|     <para>
 | ||
|       The stderr and stdout output from the diff hook will not be
 | ||
|       displayed to the user. Instead, it will print to the nix-daemon's
 | ||
|       log.
 | ||
|     </para>
 | ||
| 
 | ||
|     <para>When using the Nix daemon, <literal>diff-hook</literal> must
 | ||
|     be set in the <filename>nix.conf</filename> configuration file, and
 | ||
|     cannot be passed at the command line.
 | ||
|     </para>
 | ||
|   </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-enforce-determinism">
 | ||
|     <term><literal>enforce-determinism</literal></term>
 | ||
| 
 | ||
|     <listitem><para>See <xref linkend="conf-repeat" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-extra-sandbox-paths">
 | ||
|     <term><literal>extra-sandbox-paths</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A list of additional paths appended to
 | ||
|     <option>sandbox-paths</option>. Useful if you want to extend
 | ||
|     its default value.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-extra-platforms"><term><literal>extra-platforms</literal></term>
 | ||
| 
 | ||
|     <listitem><para>Platforms other than the native one which
 | ||
|     this machine is capable of building for. This can be useful for
 | ||
|     supporting additional architectures on compatible machines:
 | ||
|     i686-linux can be built on x86_64-linux machines (and the default
 | ||
|     for this setting reflects this); armv7 is backwards-compatible with
 | ||
|     armv6 and armv5tel; some aarch64 machines can also natively run
 | ||
|     32-bit ARM code; and qemu-user may be used to support non-native
 | ||
|     platforms (though this may be slow and buggy). Most values for this
 | ||
|     are not enabled by default because build systems will often
 | ||
|     misdetect the target platform and generate incompatible code, so you
 | ||
|     may wish to cross-check the results of using this option against
 | ||
|     proper natively-built versions of your
 | ||
|     derivations.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-extra-substituters"><term><literal>extra-substituters</literal></term>
 | ||
| 
 | ||
|     <listitem><para>Additional binary caches appended to those
 | ||
|     specified in <option>substituters</option>.  When used by
 | ||
|     unprivileged users, untrusted substituters (i.e. those not listed
 | ||
|     in <option>trusted-substituters</option>) are silently
 | ||
|     ignored.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-fallback"><term><literal>fallback</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal>, Nix will fall
 | ||
|     back to building from source if a binary substitute fails.  This
 | ||
|     is equivalent to the <option>--fallback</option> flag.  The
 | ||
|     default is <literal>false</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-fsync-metadata"><term><literal>fsync-metadata</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal>, changes to the
 | ||
|     Nix store metadata (in <filename>/nix/var/nix/db</filename>) are
 | ||
|     synchronously flushed to disk.  This improves robustness in case
 | ||
|     of system crashes, but reduces performance.  The default is
 | ||
|     <literal>true</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-hashed-mirrors"><term><literal>hashed-mirrors</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A list of web servers used by
 | ||
|     <function>builtins.fetchurl</function> to obtain files by
 | ||
|     hash. The default is
 | ||
|     <literal>http://tarballs.nixos.org/</literal>. Given a hash type
 | ||
|     <replaceable>ht</replaceable> and a base-16 hash
 | ||
|     <replaceable>h</replaceable>, Nix will try to download the file
 | ||
|     from
 | ||
|     <literal>hashed-mirror/<replaceable>ht</replaceable>/<replaceable>h</replaceable></literal>.
 | ||
|     This allows files to be downloaded even if they have disappeared
 | ||
|     from their original URI. For example, given the default mirror
 | ||
|     <literal>http://tarballs.nixos.org/</literal>, when building the derivation
 | ||
| 
 | ||
| <programlisting>
 | ||
| builtins.fetchurl {
 | ||
|   url = https://example.org/foo-1.2.3.tar.xz;
 | ||
|   sha256 = "2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae";
 | ||
| }
 | ||
| </programlisting>
 | ||
| 
 | ||
|     Nix will attempt to download this file from
 | ||
|     <literal>http://tarballs.nixos.org/sha256/2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae</literal>
 | ||
|     first. If it is not available there, if will try the original URI.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-http-connections"><term><literal>http-connections</literal></term>
 | ||
| 
 | ||
|     <listitem><para>The maximum number of parallel TCP connections
 | ||
|     used to fetch files from binary caches and by other downloads. It
 | ||
|     defaults to 25. 0 means no limit.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-keep-build-log"><term><literal>keep-build-log</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal> (the default),
 | ||
|     Nix will write the build log of a derivation (i.e. the standard
 | ||
|     output and error of its builder) to the directory
 | ||
|     <filename>/nix/var/log/nix/drvs</filename>.  The build log can be
 | ||
|     retrieved using the command <command>nix-store -l
 | ||
|     <replaceable>path</replaceable></command>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-keep-derivations"><term><literal>keep-derivations</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If <literal>true</literal> (default), the garbage
 | ||
|     collector will keep the derivations from which non-garbage store
 | ||
|     paths were built.  If <literal>false</literal>, they will be
 | ||
|     deleted unless explicitly registered as a root (or reachable from
 | ||
|     other roots).</para>
 | ||
| 
 | ||
|     <para>Keeping derivation around is useful for querying and
 | ||
|     traceability (e.g., it allows you to ask with what dependencies or
 | ||
|     options a store path was built), so by default this option is on.
 | ||
|     Turn it off to save a bit of disk space (or a lot if
 | ||
|     <literal>keep-outputs</literal> is also turned on).</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-keep-env-derivations"><term><literal>keep-env-derivations</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If <literal>false</literal> (default), derivations
 | ||
|     are not stored in Nix user environments.  That is, the derivations of
 | ||
|     any build-time-only dependencies may be garbage-collected.</para>
 | ||
| 
 | ||
|     <para>If <literal>true</literal>, when you add a Nix derivation to
 | ||
|     a user environment, the path of the derivation is stored in the
 | ||
|     user environment.  Thus, the derivation will not be
 | ||
|     garbage-collected until the user environment generation is deleted
 | ||
|     (<command>nix-env --delete-generations</command>).  To prevent
 | ||
|     build-time-only dependencies from being collected, you should also
 | ||
|     turn on <literal>keep-outputs</literal>.</para>
 | ||
| 
 | ||
|     <para>The difference between this option and
 | ||
|     <literal>keep-derivations</literal> is that this one is
 | ||
|     “sticky”: it applies to any user environment created while this
 | ||
|     option was enabled, while <literal>keep-derivations</literal>
 | ||
|     only applies at the moment the garbage collector is
 | ||
|     run.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-keep-outputs"><term><literal>keep-outputs</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If <literal>true</literal>, the garbage collector
 | ||
|     will keep the outputs of non-garbage derivations.  If
 | ||
|     <literal>false</literal> (default), outputs will be deleted unless
 | ||
|     they are GC roots themselves (or reachable from other roots).</para>
 | ||
| 
 | ||
|     <para>In general, outputs must be registered as roots separately.
 | ||
|     However, even if the output of a derivation is registered as a
 | ||
|     root, the collector will still delete store paths that are used
 | ||
|     only at build time (e.g., the C compiler, or source tarballs
 | ||
|     downloaded from the network).  To prevent it from doing so, set
 | ||
|     this option to <literal>true</literal>.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-max-build-log-size"><term><literal>max-build-log-size</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>This option defines the maximum number of bytes that a
 | ||
|       builder can write to its stdout/stderr.  If the builder exceeds
 | ||
|       this limit, it’s killed.  A value of <literal>0</literal> (the
 | ||
|       default) means that there is no limit.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-max-free"><term><literal>max-free</literal></term>
 | ||
| 
 | ||
|     <listitem><para>When a garbage collection is triggered by the
 | ||
|     <literal>min-free</literal> option, it stops as soon as
 | ||
|     <literal>max-free</literal> bytes are available. The default is
 | ||
|     infinity (i.e. delete all garbage).</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-max-jobs"><term><literal>max-jobs</literal></term>
 | ||
| 
 | ||
|     <listitem><para>This option defines the maximum number of jobs
 | ||
|     that Nix will try to build in parallel.  The default is
 | ||
|     <literal>1</literal>. The special value <literal>auto</literal>
 | ||
|     causes Nix to use the number of CPUs in your system.  <literal>0</literal>
 | ||
|     is useful when using remote builders to prevent any local builds (except for
 | ||
|     <literal>preferLocalBuild</literal> derivation attribute which executes locally
 | ||
|     regardless).  It can be
 | ||
|     overridden using the <option
 | ||
|     linkend='opt-max-jobs'>--max-jobs</option> (<option>-j</option>)
 | ||
|     command line switch.</para>
 | ||
| 
 | ||
|     <para>See also <xref linkend="chap-tuning-cores-and-jobs" />.</para>
 | ||
|     </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-max-silent-time"><term><literal>max-silent-time</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>This option defines the maximum number of seconds that a
 | ||
|       builder can go without producing any data on standard output or
 | ||
|       standard error.  This is useful (for instance in an automated
 | ||
|       build system) to catch builds that are stuck in an infinite
 | ||
|       loop, or to catch remote builds that are hanging due to network
 | ||
|       problems.  It can be overridden using the <option
 | ||
|       linkend="opt-max-silent-time">--max-silent-time</option> command
 | ||
|       line switch.</para>
 | ||
| 
 | ||
|       <para>The value <literal>0</literal> means that there is no
 | ||
|       timeout.  This is also the default.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-min-free"><term><literal>min-free</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
|       <para>When free disk space in <filename>/nix/store</filename>
 | ||
|       drops below <literal>min-free</literal> during a build, Nix
 | ||
|       performs a garbage-collection until <literal>max-free</literal>
 | ||
|       bytes are available or there is no more garbage.  A value of
 | ||
|       <literal>0</literal> (the default) disables this feature.</para>
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-narinfo-cache-negative-ttl"><term><literal>narinfo-cache-negative-ttl</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>The TTL in seconds for negative lookups. If a store path is
 | ||
|       queried from a substituter but was not found, there will be a
 | ||
|       negative lookup cached in the local disk cache database for the
 | ||
|       specified duration.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-narinfo-cache-positive-ttl"><term><literal>narinfo-cache-positive-ttl</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>The TTL in seconds for positive lookups. If a store path is
 | ||
|       queried from a substituter, the result of the query will be cached
 | ||
|       in the local disk cache database including some of the NAR
 | ||
|       metadata. The default TTL is a month, setting a shorter TTL for
 | ||
|       positive lookups can be useful for binary caches that have
 | ||
|       frequent garbage collection, in which case having a more frequent
 | ||
|       cache invalidation would prevent trying to pull the path again and
 | ||
|       failing with a hash mismatch if the build isn't reproducible.
 | ||
|       </para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-netrc-file"><term><literal>netrc-file</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to an absolute path to a <filename>netrc</filename>
 | ||
|     file, Nix will use the HTTP authentication credentials in this file when
 | ||
|     trying to download from a remote host through HTTP or HTTPS. Defaults to
 | ||
|     <filename>$NIX_CONF_DIR/netrc</filename>.</para>
 | ||
| 
 | ||
|     <para>The <filename>netrc</filename> file consists of a list of
 | ||
|     accounts in the following format:
 | ||
| 
 | ||
| <screen>
 | ||
| machine <replaceable>my-machine</replaceable>
 | ||
| login <replaceable>my-username</replaceable>
 | ||
| password <replaceable>my-password</replaceable>
 | ||
| </screen>
 | ||
| 
 | ||
|     For the exact syntax, see <link
 | ||
|     xlink:href="https://ec.haxx.se/usingcurl-netrc.html">the
 | ||
|     <literal>curl</literal> documentation.</link></para>
 | ||
| 
 | ||
|     <note><para>This must be an absolute path, and <literal>~</literal>
 | ||
|     is not resolved. For example, <filename>~/.netrc</filename> won't
 | ||
|     resolve to your home directory's <filename>.netrc</filename>.</para></note>
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-plugin-files">
 | ||
|     <term><literal>plugin-files</literal></term>
 | ||
|     <listitem>
 | ||
|       <para>
 | ||
|         A list of plugin files to be loaded by Nix. Each of these
 | ||
|         files will be dlopened by Nix, allowing them to affect
 | ||
|         execution through static initialization. In particular, these
 | ||
|         plugins may construct static instances of RegisterPrimOp to
 | ||
|         add new primops or constants to the expression language,
 | ||
|         RegisterStoreImplementation to add new store implementations,
 | ||
|         RegisterCommand to add new subcommands to the
 | ||
|         <literal>nix</literal> command, and RegisterSetting to add new
 | ||
|         nix config settings. See the constructors for those types for
 | ||
|         more details.
 | ||
|       </para>
 | ||
|       <para>
 | ||
|         Since these files are loaded into the same address space as
 | ||
|         Nix itself, they must be DSOs compatible with the instance of
 | ||
|         Nix running at the time (i.e. compiled against the same
 | ||
|         headers, not linked to any incompatible libraries). They
 | ||
|         should not be linked to any Nix libs directly, as those will
 | ||
|         be available already at load time.
 | ||
|       </para>
 | ||
|       <para>
 | ||
|         If an entry in the list is a directory, all files in the
 | ||
|         directory are loaded as plugins (non-recursively).
 | ||
|       </para>
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-pre-build-hook"><term><literal>pre-build-hook</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
| 
 | ||
|       <para>If set, the path to a program that can set extra
 | ||
|       derivation-specific settings for this system. This is used for settings
 | ||
|       that can't be captured by the derivation model itself and are too variable
 | ||
|       between different versions of the same system to be hard-coded into nix.
 | ||
|       </para>
 | ||
| 
 | ||
|       <para>The hook is passed the derivation path and, if sandboxes are enabled,
 | ||
|       the sandbox directory. It can then modify the sandbox and send a series of
 | ||
|       commands to modify various settings to stdout. The currently recognized
 | ||
|       commands are:</para>
 | ||
| 
 | ||
|       <variablelist>
 | ||
|         <varlistentry xml:id="extra-sandbox-paths">
 | ||
|           <term><literal>extra-sandbox-paths</literal></term>
 | ||
| 
 | ||
|           <listitem>
 | ||
| 
 | ||
|             <para>Pass a list of files and directories to be included in the
 | ||
|             sandbox for this build. One entry per line, terminated by an empty
 | ||
|             line. Entries have the same format as
 | ||
|             <literal>sandbox-paths</literal>.</para>
 | ||
| 
 | ||
|           </listitem>
 | ||
| 
 | ||
|         </varlistentry>
 | ||
|       </variablelist>
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-post-build-hook">
 | ||
|     <term><literal>post-build-hook</literal></term>
 | ||
|     <listitem>
 | ||
|       <para>Optional. The path to a program to execute after each build.</para>
 | ||
| 
 | ||
|       <para>This option is only settable in the global
 | ||
|       <filename>nix.conf</filename>, or on the command line by trusted
 | ||
|       users.</para>
 | ||
| 
 | ||
|       <para>When using the nix-daemon, the daemon executes the hook as
 | ||
|       <literal>root</literal>. If the nix-daemon is not involved, the
 | ||
|       hook runs as the user executing the nix-build.</para>
 | ||
| 
 | ||
|       <itemizedlist>
 | ||
|         <listitem><para>The hook executes after an evaluation-time build.</para></listitem>
 | ||
|         <listitem><para>The hook does not execute on substituted paths.</para></listitem>
 | ||
|         <listitem><para>The hook's output always goes to the user's terminal.</para></listitem>
 | ||
|         <listitem><para>If the hook fails, the build succeeds but no further builds execute.</para></listitem>
 | ||
|         <listitem><para>The hook executes synchronously, and blocks other builds from progressing while it runs.</para></listitem>
 | ||
|       </itemizedlist>
 | ||
| 
 | ||
|       <para>The program executes with no arguments. The program's environment
 | ||
|       contains the following environment variables:</para>
 | ||
| 
 | ||
|       <variablelist>
 | ||
|         <varlistentry>
 | ||
|           <term><envar>DRV_PATH</envar></term>
 | ||
|           <listitem>
 | ||
|             <para>The derivation for the built paths.</para>
 | ||
|             <para>Example:
 | ||
|             <literal>/nix/store/5nihn1a7pa8b25l9zafqaqibznlvvp3f-bash-4.4-p23.drv</literal>
 | ||
|             </para>
 | ||
|           </listitem>
 | ||
|         </varlistentry>
 | ||
| 
 | ||
|         <varlistentry>
 | ||
|           <term><envar>OUT_PATHS</envar></term>
 | ||
|           <listitem>
 | ||
|             <para>Output paths of the built derivation, separated by a space character.</para>
 | ||
|             <para>Example:
 | ||
|             <literal>/nix/store/zf5lbh336mnzf1nlswdn11g4n2m8zh3g-bash-4.4-p23-dev
 | ||
|             /nix/store/rjxwxwv1fpn9wa2x5ssk5phzwlcv4mna-bash-4.4-p23-doc
 | ||
|             /nix/store/6bqvbzjkcp9695dq0dpl5y43nvy37pq1-bash-4.4-p23-info
 | ||
|             /nix/store/r7fng3kk3vlpdlh2idnrbn37vh4imlj2-bash-4.4-p23-man
 | ||
|             /nix/store/xfghy8ixrhz3kyy6p724iv3cxji088dx-bash-4.4-p23</literal>.
 | ||
|             </para>
 | ||
|           </listitem>
 | ||
|         </varlistentry>
 | ||
|       </variablelist>
 | ||
| 
 | ||
|       <para>See <xref linkend="chap-post-build-hook" /> for an example
 | ||
|       implementation.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-repeat"><term><literal>repeat</literal></term>
 | ||
| 
 | ||
|     <listitem><para>How many times to repeat builds to check whether
 | ||
|     they are deterministic. The default value is 0. If the value is
 | ||
|     non-zero, every build is repeated the specified number of
 | ||
|     times. If the contents of any of the runs differs from the
 | ||
|     previous ones and <xref linkend="conf-enforce-determinism" /> is
 | ||
|     true, the build is rejected and the resulting store paths are not
 | ||
|     registered as “valid” in Nix’s database.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-require-sigs"><term><literal>require-sigs</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal> (the default),
 | ||
|     any non-content-addressed path added or copied to the Nix store
 | ||
|     (e.g. when substituting from a binary cache) must have a valid
 | ||
|     signature, that is, be signed using one of the keys listed in
 | ||
|     <option>trusted-public-keys</option> or
 | ||
|     <option>secret-key-files</option>. Set to <literal>false</literal>
 | ||
|     to disable signature checking.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-restrict-eval"><term><literal>restrict-eval</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>If set to <literal>true</literal>, the Nix evaluator will
 | ||
|       not allow access to any files outside of the Nix search path (as
 | ||
|       set via the <envar>NIX_PATH</envar> environment variable or the
 | ||
|       <option>-I</option> option), or to URIs outside of
 | ||
|       <option>allowed-uri</option>. The default is
 | ||
|       <literal>false</literal>.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-run-diff-hook"><term><literal>run-diff-hook</literal></term>
 | ||
|   <listitem>
 | ||
|     <para>
 | ||
|       If true, enable the execution of <xref linkend="conf-diff-hook" />.
 | ||
|     </para>
 | ||
| 
 | ||
|     <para>
 | ||
|       When using the Nix daemon, <literal>run-diff-hook</literal> must
 | ||
|       be set in the <filename>nix.conf</filename> configuration file,
 | ||
|       and cannot be passed at the command line.
 | ||
|     </para>
 | ||
|   </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-sandbox"><term><literal>sandbox</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal>, builds will be
 | ||
|     performed in a <emphasis>sandboxed environment</emphasis>, i.e.,
 | ||
|     they’re isolated from the normal file system hierarchy and will
 | ||
|     only see their dependencies in the Nix store, the temporary build
 | ||
|     directory, private versions of <filename>/proc</filename>,
 | ||
|     <filename>/dev</filename>, <filename>/dev/shm</filename> and
 | ||
|     <filename>/dev/pts</filename> (on Linux), and the paths configured with the
 | ||
|     <link linkend='conf-sandbox-paths'><literal>sandbox-paths</literal>
 | ||
|     option</link>. This is useful to prevent undeclared dependencies
 | ||
|     on files in directories such as <filename>/usr/bin</filename>. In
 | ||
|     addition, on Linux, builds run in private PID, mount, network, IPC
 | ||
|     and UTS namespaces to isolate them from other processes in the
 | ||
|     system (except that fixed-output derivations do not run in private
 | ||
|     network namespace to ensure they can access the network).</para>
 | ||
| 
 | ||
|     <para>Currently, sandboxing only work on Linux and macOS. The use
 | ||
|     of a sandbox requires that Nix is run as root (so you should use
 | ||
|     the <link linkend='conf-build-users-group'>“build users”
 | ||
|     feature</link> to perform the actual builds under different users
 | ||
|     than root).</para>
 | ||
| 
 | ||
|     <para>If this option is set to <literal>relaxed</literal>, then
 | ||
|     fixed-output derivations and derivations that have the
 | ||
|     <varname>__noChroot</varname> attribute set to
 | ||
|     <literal>true</literal> do not run in sandboxes.</para>
 | ||
| 
 | ||
|     <para>The default is <literal>true</literal> on Linux and
 | ||
|     <literal>false</literal> on all other platforms.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-sandbox-dev-shm-size"><term><literal>sandbox-dev-shm-size</literal></term>
 | ||
| 
 | ||
|     <listitem><para>This option determines the maximum size of the
 | ||
|     <literal>tmpfs</literal> filesystem mounted on
 | ||
|     <filename>/dev/shm</filename> in Linux sandboxes. For the format,
 | ||
|     see the description of the <option>size</option> option of
 | ||
|     <literal>tmpfs</literal> in
 | ||
|     <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>. The
 | ||
|     default is <literal>50%</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-sandbox-paths">
 | ||
|     <term><literal>sandbox-paths</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A list of paths bind-mounted into Nix sandbox
 | ||
|     environments. You can use the syntax
 | ||
|     <literal><replaceable>target</replaceable>=<replaceable>source</replaceable></literal>
 | ||
|     to mount a path in a different location in the sandbox; for
 | ||
|     instance, <literal>/bin=/nix-bin</literal> will mount the path
 | ||
|     <literal>/nix-bin</literal> as <literal>/bin</literal> inside the
 | ||
|     sandbox. If <replaceable>source</replaceable> is followed by
 | ||
|     <literal>?</literal>, then it is not an error if
 | ||
|     <replaceable>source</replaceable> does not exist; for example,
 | ||
|     <literal>/dev/nvidiactl?</literal> specifies that
 | ||
|     <filename>/dev/nvidiactl</filename> will only be mounted in the
 | ||
|     sandbox if it exists in the host filesystem.</para>
 | ||
| 
 | ||
|     <para>Depending on how Nix was built, the default value for this option
 | ||
|     may be empty or provide <filename>/bin/sh</filename> as a
 | ||
|     bind-mount of <command>bash</command>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-secret-key-files"><term><literal>secret-key-files</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A whitespace-separated list of files containing
 | ||
|     secret (private) keys. These are used to sign locally-built
 | ||
|     paths. They can be generated using <command>nix-store
 | ||
|     --generate-binary-cache-key</command>. The corresponding public
 | ||
|     key can be distributed to other users, who can add it to
 | ||
|     <option>trusted-public-keys</option> in their
 | ||
|     <filename>nix.conf</filename>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-show-trace"><term><literal>show-trace</literal></term>
 | ||
| 
 | ||
|     <listitem><para>Causes Nix to print out a stack trace in case of Nix
 | ||
|     expression evaluation errors.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-substitute"><term><literal>substitute</literal></term>
 | ||
| 
 | ||
|     <listitem><para>If set to <literal>true</literal> (default), Nix
 | ||
|     will use binary substitutes if available.  This option can be
 | ||
|     disabled to force building from source.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-stalled-download-timeout"><term><literal>stalled-download-timeout</literal></term>
 | ||
|     <listitem>
 | ||
|       <para>The timeout (in seconds) for receiving data from servers
 | ||
|       during download. Nix cancels idle downloads after this timeout's
 | ||
|       duration.</para>
 | ||
|     </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-substituters"><term><literal>substituters</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A list of URLs of substituters, separated by
 | ||
|     whitespace.  The default is
 | ||
|     <literal>https://cache.nixos.org</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-system"><term><literal>system</literal></term>
 | ||
| 
 | ||
|     <listitem><para>This option specifies the canonical Nix system
 | ||
|     name of the current installation, such as
 | ||
|     <literal>i686-linux</literal> or
 | ||
|     <literal>x86_64-darwin</literal>.  Nix can only build derivations
 | ||
|     whose <literal>system</literal> attribute equals the value
 | ||
|     specified here.  In general, it never makes sense to modify this
 | ||
|     value from its default, since you can use it to ‘lie’ about the
 | ||
|     platform you are building on (e.g., perform a Mac OS build on a
 | ||
|     Linux machine; the result would obviously be wrong).  It only
 | ||
|     makes sense if the Nix binaries can run on multiple platforms,
 | ||
|     e.g., ‘universal binaries’ that run on <literal>x86_64-linux</literal> and
 | ||
|     <literal>i686-linux</literal>.</para>
 | ||
| 
 | ||
|     <para>It defaults to the canonical Nix system name detected by
 | ||
|     <filename>configure</filename> at build time.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-system-features"><term><literal>system-features</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A set of system “features” supported by this
 | ||
|     machine, e.g. <literal>kvm</literal>. Derivations can express a
 | ||
|     dependency on such features through the derivation attribute
 | ||
|     <varname>requiredSystemFeatures</varname>. For example, the
 | ||
|     attribute
 | ||
| 
 | ||
| <programlisting>
 | ||
| requiredSystemFeatures = [ "kvm" ];
 | ||
| </programlisting>
 | ||
| 
 | ||
|     ensures that the derivation can only be built on a machine with
 | ||
|     the <literal>kvm</literal> feature.</para>
 | ||
| 
 | ||
|     <para>This setting by default includes <literal>kvm</literal> if
 | ||
|     <filename>/dev/kvm</filename> is accessible, and the
 | ||
|     pseudo-features <literal>nixos-test</literal>,
 | ||
|     <literal>benchmark</literal> and <literal>big-parallel</literal>
 | ||
|     that are used in Nixpkgs to route builds to specific
 | ||
|     machines.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-tarball-ttl"><term><literal>tarball-ttl</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
|       <para>Default: <literal>3600</literal> seconds.</para>
 | ||
| 
 | ||
|       <para>The number of seconds a downloaded tarball is considered
 | ||
|       fresh. If the cached tarball is stale, Nix will check whether
 | ||
|       it is still up to date using the ETag header. Nix will download
 | ||
|       a new version if the ETag header is unsupported, or the
 | ||
|       cached ETag doesn't match.
 | ||
|       </para>
 | ||
| 
 | ||
|       <para>Setting the TTL to <literal>0</literal> forces Nix to always
 | ||
|       check if the tarball is up to date.</para>
 | ||
| 
 | ||
|       <para>Nix caches tarballs in
 | ||
|       <filename>$XDG_CACHE_HOME/nix/tarballs</filename>.</para>
 | ||
| 
 | ||
|       <para>Files fetched via <envar>NIX_PATH</envar>,
 | ||
|       <function>fetchGit</function>, <function>fetchMercurial</function>,
 | ||
|       <function>fetchTarball</function>, and <function>fetchurl</function>
 | ||
|       respect this TTL.
 | ||
|       </para>
 | ||
|     </listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-timeout"><term><literal>timeout</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>This option defines the maximum number of seconds that a
 | ||
|       builder can run.  This is useful (for instance in an automated
 | ||
|       build system) to catch builds that are stuck in an infinite loop
 | ||
|       but keep writing to their standard output or standard error.  It
 | ||
|       can be overridden using the <option
 | ||
|       linkend="opt-timeout">--timeout</option> command line
 | ||
|       switch.</para>
 | ||
| 
 | ||
|       <para>The value <literal>0</literal> means that there is no
 | ||
|       timeout.  This is also the default.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-trace-function-calls"><term><literal>trace-function-calls</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>Default: <literal>false</literal>.</para>
 | ||
| 
 | ||
|       <para>If set to <literal>true</literal>, the Nix evaluator will
 | ||
|       trace every function call. Nix will print a log message at the
 | ||
|       "vomit" level for every function entrance and function exit.</para>
 | ||
| 
 | ||
|       <informalexample><screen>
 | ||
| function-trace entered undefined position at 1565795816999559622
 | ||
| function-trace exited undefined position at 1565795816999581277
 | ||
| function-trace entered /nix/store/.../example.nix:226:41 at 1565795253249935150
 | ||
| function-trace exited /nix/store/.../example.nix:226:41 at 1565795253249941684
 | ||
| </screen></informalexample>
 | ||
| 
 | ||
|       <para>The <literal>undefined position</literal> means the function
 | ||
|       call is a builtin.</para>
 | ||
| 
 | ||
|       <para>Use the <literal>contrib/stack-collapse.py</literal> script
 | ||
|       distributed with the Nix source code to convert the trace logs
 | ||
|       in to a format suitable for <command>flamegraph.pl</command>.</para>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-trusted-public-keys"><term><literal>trusted-public-keys</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A whitespace-separated list of public keys. When
 | ||
|     paths are copied from another Nix store (such as a binary cache),
 | ||
|     they must be signed with one of these keys. For example:
 | ||
|     <literal>cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
 | ||
|     hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-trusted-substituters"><term><literal>trusted-substituters</literal></term>
 | ||
| 
 | ||
|     <listitem><para>A list of URLs of substituters, separated by
 | ||
|     whitespace.  These are not used by default, but can be enabled by
 | ||
|     users of the Nix daemon by specifying <literal>--option
 | ||
|     substituters <replaceable>urls</replaceable></literal> on the
 | ||
|     command line.  Unprivileged users are only allowed to pass a
 | ||
|     subset of the URLs listed in <literal>substituters</literal> and
 | ||
|     <literal>trusted-substituters</literal>.</para></listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-trusted-users"><term><literal>trusted-users</literal></term>
 | ||
| 
 | ||
|     <listitem>
 | ||
| 
 | ||
|       <para>A list of names of users (separated by whitespace) that
 | ||
|       have additional rights when connecting to the Nix daemon, such
 | ||
|       as the ability to specify additional binary caches, or to import
 | ||
|       unsigned NARs. You can also specify groups by prefixing them
 | ||
|       with <literal>@</literal>; for instance,
 | ||
|       <literal>@wheel</literal> means all users in the
 | ||
|       <literal>wheel</literal> group. The default is
 | ||
|       <literal>root</literal>.</para>
 | ||
| 
 | ||
|       <warning><para>Adding a user to <option>trusted-users</option>
 | ||
|       is essentially equivalent to giving that user root access to the
 | ||
|       system. For example, the user can set
 | ||
|       <option>sandbox-paths</option> and thereby obtain read access to
 | ||
|       directories that are otherwise inacessible to
 | ||
|       them.</para></warning>
 | ||
| 
 | ||
|     </listitem>
 | ||
| 
 | ||
|   </varlistentry>
 | ||
| 
 | ||
| </variablelist>
 | ||
| </para>
 | ||
| 
 | ||
| <refsection>
 | ||
|   <title>Deprecated Settings</title>
 | ||
| 
 | ||
| <para>
 | ||
| 
 | ||
| <variablelist>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-binary-caches">
 | ||
|     <term><literal>binary-caches</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>binary-caches</literal> is now an alias to
 | ||
|     <xref linkend="conf-substituters" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-binary-cache-public-keys">
 | ||
|     <term><literal>binary-cache-public-keys</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>binary-cache-public-keys</literal> is now an alias to
 | ||
|     <xref linkend="conf-trusted-public-keys" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-compress-log">
 | ||
|     <term><literal>build-compress-log</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-compress-log</literal> is now an alias to
 | ||
|     <xref linkend="conf-compress-build-log" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-cores">
 | ||
|     <term><literal>build-cores</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-cores</literal> is now an alias to
 | ||
|     <xref linkend="conf-cores" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-extra-chroot-dirs">
 | ||
|     <term><literal>build-extra-chroot-dirs</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-extra-chroot-dirs</literal> is now an alias to
 | ||
|     <xref linkend="conf-extra-sandbox-paths" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-extra-sandbox-paths">
 | ||
|     <term><literal>build-extra-sandbox-paths</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-extra-sandbox-paths</literal> is now an alias to
 | ||
|     <xref linkend="conf-extra-sandbox-paths" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-fallback">
 | ||
|     <term><literal>build-fallback</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-fallback</literal> is now an alias to
 | ||
|     <xref linkend="conf-fallback" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-max-jobs">
 | ||
|     <term><literal>build-max-jobs</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-max-jobs</literal> is now an alias to
 | ||
|     <xref linkend="conf-max-jobs" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-max-log-size">
 | ||
|     <term><literal>build-max-log-size</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-max-log-size</literal> is now an alias to
 | ||
|     <xref linkend="conf-max-build-log-size" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-max-silent-time">
 | ||
|     <term><literal>build-max-silent-time</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-max-silent-time</literal> is now an alias to
 | ||
|     <xref linkend="conf-max-silent-time" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-repeat">
 | ||
|     <term><literal>build-repeat</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-repeat</literal> is now an alias to
 | ||
|     <xref linkend="conf-repeat" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-timeout">
 | ||
|     <term><literal>build-timeout</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-timeout</literal> is now an alias to
 | ||
|     <xref linkend="conf-timeout" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-use-chroot">
 | ||
|     <term><literal>build-use-chroot</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-use-chroot</literal> is now an alias to
 | ||
|     <xref linkend="conf-sandbox" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-use-sandbox">
 | ||
|     <term><literal>build-use-sandbox</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-use-sandbox</literal> is now an alias to
 | ||
|     <xref linkend="conf-sandbox" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-build-use-substitutes">
 | ||
|     <term><literal>build-use-substitutes</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>build-use-substitutes</literal> is now an alias to
 | ||
|     <xref linkend="conf-substitute" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-gc-keep-derivations">
 | ||
|     <term><literal>gc-keep-derivations</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>gc-keep-derivations</literal> is now an alias to
 | ||
|     <xref linkend="conf-keep-derivations" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-gc-keep-outputs">
 | ||
|     <term><literal>gc-keep-outputs</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>gc-keep-outputs</literal> is now an alias to
 | ||
|     <xref linkend="conf-keep-outputs" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-env-keep-derivations">
 | ||
|     <term><literal>env-keep-derivations</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>env-keep-derivations</literal> is now an alias to
 | ||
|     <xref linkend="conf-keep-env-derivations" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-extra-binary-caches">
 | ||
|     <term><literal>extra-binary-caches</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>extra-binary-caches</literal> is now an alias to
 | ||
|     <xref linkend="conf-extra-substituters" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| 
 | ||
|   <varlistentry xml:id="conf-trusted-binary-caches">
 | ||
|     <term><literal>trusted-binary-caches</literal></term>
 | ||
| 
 | ||
|     <listitem><para><emphasis>Deprecated:</emphasis>
 | ||
|     <literal>trusted-binary-caches</literal> is now an alias to
 | ||
|     <xref linkend="conf-trusted-substituters" />.</para></listitem>
 | ||
|   </varlistentry>
 | ||
| </variablelist>
 | ||
| </para>
 | ||
| </refsection>
 | ||
| 
 | ||
| </refsection>
 | ||
| 
 | ||
| </refentry>
 |