guix/doc/manual/nix-push.xml

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<refentry xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink">
<refnamediv>
<refname>nix-push</refname>
<refpurpose>push store paths onto a network cache</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>nix-push</command>
<group choice='req'>
<arg choice='req'>
<arg choice='plain'><replaceable>archivesPutURL</replaceable></arg>
<arg choice='plain'><replaceable>archivesGetURL</replaceable></arg>
<arg choice='plain'><replaceable>manifestPutURL</replaceable></arg>
</arg>
<arg choice='req'>
<arg choice='plain'><option>--copy</option></arg>
<arg choice='plain'><replaceable>archivesDir</replaceable></arg>
<arg choice='plain'><replaceable>manifestFile</replaceable></arg>
</arg>
</group>
<arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsection><title>Description</title>
<para>The command <command>nix-push</command> builds a set of store
paths (if necessary), and then packages and uploads all store paths in
the resulting closures to a server. A network cache thus populated
can subsequently be used to speed up software deployment on other
machines using the <command>nix-pull</command> command.</para>
<para><command>nix-push</command> performs the following actions.
<orderedlist>
<listitem><para>Each path in <replaceable>paths</replaceable> is
realised (using <link
linkend='rsec-nix-store-realise'><literal>nix-store
--realise</literal></link>).</para></listitem>
<listitem><para>All paths in the closure of the store expressions
stored in <replaceable>paths</replaceable> are determined (using
<literal>nix-store --query --requisites
--include-outputs</literal>). It should be noted that since the
<option>--include-outputs</option> flag is used, you get a combined
source/binary distribution.</para></listitem>
<listitem><para>All store paths determined in the previous step are
packaged and compressed into a <command>bzip</command>ped NAR
archive (extension <filename>.nar.bz2</filename>).</para></listitem>
<listitem><para>A <emphasis>manifest</emphasis> is created that
contains information on the store paths, their eventual URLs in the
cache, and cryptographic hashes of the contents of the NAR
archives.</para></listitem>
<listitem><para>Each store path is uploaded to the remote directory
specified by <replaceable>archivesPutURL</replaceable>. HTTP PUT
requests are used to do this. However, before a file
<varname>x</varname> is uploaded to
<literal><replaceable>archivesPutURL</replaceable>/</literal><varname>x</varname>,
<command>nix-push</command> first determines whether this upload is
unnecessary by issuing a HTTP HEAD request on
<literal><replaceable>archivesGetURL</replaceable>/</literal><varname>x</varname>.
This allows a cache to be shared between many partially overlapping
<command>nix-push</command> invocations. (We use two URLs because
the upload URL typically refers to a CGI script, while the download
URL just refers to a file system directory on the
server.)</para></listitem>
<listitem><para>The manifest is uploaded using an HTTP PUT request
to <replaceable>manifestPutURL</replaceable>. The corresponding
URL to download the manifest can then be used by
<command>nix-pull</command>.</para></listitem>
</orderedlist>
</para>
<para>TODO: <option>--copy</option></para>
</refsection>
<refsection><title>Examples</title>
<para>To upload files there typically is some CGI script on the server
side. This script should be be protected with a password. The
following example uploads the store paths resulting from building the
Nix expressions in <filename>foo.nix</filename>, passing appropriate
authentication information:
<screen>
$ nix-push \
http://foo@bar:server.domain/cgi-bin/upload.pl/cache \
http://server.domain/cache \
http://foo@bar:server.domain/cgi-bin/upload.pl/MANIFEST \
$(nix-instantiate foo.nix)</screen>
This will push both sources and binaries (and any build-time
dependencies used in the build, such as compilers).</para>
<para>If we just want to push binaries, not sources and build-time
dependencies, we can do:
<screen>
$ nix-push <replaceable>urls</replaceable> $(nix-instantiate $(nix-store -r foo.nix))</screen>
</para>
</refsection>
</refentry>