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lix/doc/manual/nix-push.xml

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<refentry>
<refnamediv>
<refname>nix-push</refname>
<refpurpose>push store paths onto a network cache</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>nix-push</command>
<arg choice='plain'><replaceable>archives-put-url</replaceable></arg>
<arg choice='plain'><replaceable>archives-get-url</replaceable></arg>
<arg choice='plain'><replaceable>manifest-put-url</replaceable></arg>
<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
expressions (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>
The store expressions stored in
<replaceable>paths</replaceable> are realised (using
<literal>nix-store --realise</literal>).
</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-successors</literal>). It should be noted that
since the <option>--include-successors</option> flag is
used, if you specify a derivation store expression, you
get a combined source/binary distribution. If you only
want a binary distribution, you should specify the closure
store expression that result from realising these (see
below).
</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>archives-put-url</replaceable>.
HTTP PUT requests are used to do this. However, before a
file <varname>x</varname> is uploaded to
<literal><replaceable>archives-put-url</replaceable>/<varname>x</varname></literal>,
<command>nix-push</command> first determines whether this
upload is unnecessary by issuing a HTTP HEAD request on
<literal><replaceable>archives-get-url</replaceable>/<varname>x</varname></literal>.
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>manifest-put-url</replaceable>. The
corresponding URL to download the manifest can then be
used by <command>nix-pull</command>.
</para>
</listitem>
</orderedlist>
</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>