systemd/man/org.freedesktop.import1.xml
2020-11-09 13:23:58 +09:00

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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" >
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="org.freedesktop.import1" conditional='ENABLE_IMPORTD'
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>org.freedesktop.import1</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>org.freedesktop.import1</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>org.freedesktop.import1</refname>
<refpurpose>The D-Bus interface of systemd-importd</refpurpose>
</refnamediv>
<refsect1>
<title>Introduction</title>
<para>
<citerefentry><refentrytitle>systemd-importd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
is a system service which may be used to import, export and download additional system images. These
images can be used by tools such as
<citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
to run local containers. The service is used as the backend for <command>machinectl pull-raw</command>,
<command>machinectl pull-tar</command> and related commands. This page describes the D-Bus interface.
</para>
<para>Note that
<citerefentry><refentrytitle>systemd-importd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
is mostly a small companion service for
<citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
Many operations to manipulate local container and VM images are hence available via the <command>systemd-machined</command> D-Bus API, c.f.
<citerefentry><refentrytitle>org.freedesktop.machine1</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
</para>
</refsect1>
<refsect1>
<title>The Manager Object</title>
<para>The service exposes the following interfaces on the Manager object on the bus:</para>
<programlisting executable="systemd-importd" node="/org/freedesktop/import1" interface="org.freedesktop.import1.Manager">
node /org/freedesktop/import1 {
interface org.freedesktop.import1.Manager {
methods:
ImportTar(in h fd,
in s local_name,
in b force,
in b read_only,
out u transfer_id,
out o transfer_path);
ImportRaw(in h fd,
in s local_name,
in b force,
in b read_only,
out u transfer_id,
out o transfer_path);
ImportFileSystem(in h fd,
in s local_name,
in b force,
in b read_only,
out u transfer_id,
out o transfer_path);
ExportTar(in s local_name,
in h fd,
in s format,
out u transfer_id,
out o transfer_path);
ExportRaw(in s local_name,
in h fd,
in s format,
out u transfer_id,
out o transfer_path);
PullTar(in s url,
in s local_name,
in s verify_mode,
in b force,
out u transfer_id,
out o transfer_path);
PullRaw(in s url,
in s local_name,
in s verify_mode,
in b force,
out u transfer_id,
out o transfer_path);
ListTransfers(out a(usssdo) transfers);
CancelTransfer(in u transfer_id);
signals:
TransferNew(u transfer_id,
o transfer_path);
TransferRemoved(u transfer_id,
o transfer_path,
s result);
};
interface org.freedesktop.DBus.Peer { ... };
interface org.freedesktop.DBus.Introspectable { ... };
interface org.freedesktop.DBus.Properties { ... };
};
</programlisting>
<!--method ImportFileSystem is not documented!-->
<!--Autogenerated cross-references for systemd.directives, do not edit-->
<variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.import1.Manager"/>
<variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.import1.Manager"/>
<variablelist class="dbus-method" generated="True" extra-ref="ImportTar()"/>
<variablelist class="dbus-method" generated="True" extra-ref="ImportRaw()"/>
<variablelist class="dbus-method" generated="True" extra-ref="ImportFileSystem()"/>
<variablelist class="dbus-method" generated="True" extra-ref="ExportTar()"/>
<variablelist class="dbus-method" generated="True" extra-ref="ExportRaw()"/>
<variablelist class="dbus-method" generated="True" extra-ref="PullTar()"/>
<variablelist class="dbus-method" generated="True" extra-ref="PullRaw()"/>
<variablelist class="dbus-method" generated="True" extra-ref="ListTransfers()"/>
<variablelist class="dbus-method" generated="True" extra-ref="CancelTransfer()"/>
<variablelist class="dbus-signal" generated="True" extra-ref="TransferNew"/>
<variablelist class="dbus-signal" generated="True" extra-ref="TransferRemoved"/>
<!--End of Autogenerated section-->
<refsect2>
<title>Methods</title>
<para><function>ImportTar()</function> and <function>ImportRaw()</function> import a system image and
place it into <filename>/var/lib/machines/</filename>. The first argument should be a file descriptor
(opened for reading) referring to the tar or raw file to import. It should reference a file on disk,
a pipe or a socket. When <function>ImportTar()</function> is used the file descriptor should
refer to a tar file, optionally compressed with
<citerefentry project="die-net"><refentrytitle>gzip</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry project="die-net"><refentrytitle>bzip2</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
or
<citerefentry project="die-net"><refentrytitle>xz</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
<command>systemd-importd</command> will detect the used compression scheme (if any) automatically. When
<function>ImportRaw()</function> is used the file descriptor should refer to a raw or qcow2 disk image
containing an MBR or GPT disk label, also optionally compressed with gzip, bzip2 or xz. In either case,
if the file is specified as a file descriptor on disk, progress information is generated for the import
operation (as in that case we know the total size on disk). If a socket or pipe is specified, progress information is not
available. The file descriptor argument is followed by a local name for the image. This should be a
name suitable as a hostname and will be used to name the imported image below
<filename>/var/lib/machines/</filename>. A tar import is placed as a directory tree or a
<citerefentry project="man-pages"><refentrytitle>btrfs</refentrytitle><manvolnum>8</manvolnum></citerefentry>
subvolume below <filename>/var/lib/machines/</filename> under the specified name with no suffix
appended. A raw import is placed as a file in <filename>/var/lib/machines/</filename> with the
<filename>.raw</filename> suffix appended. If the <option>force</option> argument is true, any
pre-existing image with the same name is removed before starting the operation. Otherwise, the
operation fails if an image with the same name already exists. Finally, the
<option>read_only</option> argument controls
whether to create a writable or read-only image. Both methods return immediately after starting the import,
with the import transfer ongoing. They return a pair of transfer identifier and object path, which may
be used to retrieve progress information about the transfer or to cancel it. The transfer identifier is a
simple numeric identifier, the object path references an
<interfacename>org.freedesktop.import1.Transfer</interfacename> object, see below. Listen for a
<function>TransferRemoved</function> signal for the transfer ID in order to detect when a transfer is
complete. The returned transfer object is useful to determine the current progress or log output of the
ongoing import operation.</para>
<para><function>ExportTar()</function> and <function>ExportRaw()</function> implement the reverse
operation, and may be used to export a system image in order to place it in a tar or raw image. They
take the machine name to export as their first parameter, followed by a file descriptor (opened for writing)
where the tar or raw file will be written. It may either reference a file on disk or a pipe/socket. The
third argument specifies in which compression format to write the image. It takes one of
<literal>uncompressed</literal>, <literal>xz</literal>, <literal>bzip2</literal> or
<literal>gzip</literal>, depending on which compression scheme is required. The image written to the
specified file descriptor will be a tar file in case of <function>ExportTar()</function> or a raw disk
image in case of <function>ExportRaw()</function>. Note that currently raw disk images may not be
exported as tar files, and vice versa. This restriction might be lifted eventually. The method
returns a transfer identifier and object path for cancelling or tracking the export operation, similar
to <function>ImportTar()</function> or <function>ImportRaw()</function> as described above.</para>
<para><function>PullTar()</function> and <function>PullRaw()</function> may be used to download, verify
and import a system image from a URL. They take an URL argument which should point to a tar or
raw file on the <literal>http://</literal> or <literal>https://</literal> protocols, possibly
compressed with xz, bzip2 or gzip. The second argument is a local name for the image. It should be
suitable as a hostname, similar to the matching argument of the <function>ImportTar()</function> and
<function>ImportRaw()</function> methods above. The third argument indicates the verification mode for
the image. It may be one of <literal>no</literal>, <literal>checksum</literal>,
<literal>signature</literal>. <literal>no</literal> turns off any kind of verification of the image;
<literal>checksum</literal> looks for a <filename>SHA256SUM</filename> file next to the downloaded
image and verifies any SHA256 hash value in that file against the image; <literal>signature</literal>
does the same but also tries to authenticate the <filename>SHA256SUM</filename> file via
<citerefentry project="man-pages"><refentrytitle>gpg</refentrytitle><manvolnum>8</manvolnum></citerefentry>
first. The last argument indicates whether to replace a possibly pre-existing image with the same local
name (if <literal>true</literal>), or whether to fail (if <literal>false</literal>). Like the import
and export calls above, these calls return a pair of transfer identifier and object path for the ongoing
download.</para>
<para><function>ListTransfers()</function> returns a list of ongoing import, export or download
operations as created with the six calls described above. It returns an array of structures which
consist of the numeric transfer identifier, a string indicating the operation (one of
<literal>import-tar</literal>, <literal>import-raw</literal>, <literal>export-tar</literal>,
<literal>export-raw</literal>, <literal>pull-tar</literal> or <literal>pull-raw</literal>), a string
describing the remote file (in case of download operations this is the source URL, in case of
import/export operations this is a short string describing the file descriptor passed in), a string
with the local machine image name, a progress value between 0.0 (for 0%) and 1.0 (for 100%), as well as
the transfer object path.</para>
<para><function>CancelTransfer()</function> may be used to cancel an ongoing import, export or download
operation. Simply specify the transfer identifier to cancel the ongoing operation.</para>
</refsect2>
<refsect2>
<title>Signals</title>
<para>The <function>TransferNew</function> signal is generated each time a new transfer is started with
the import, export or download calls described above. It carries the transfer ID and object path that
have just been created.</para>
<para>The <function>TransferRemoved</function> signal is sent each time a transfer finishes,
is canceled or fails. It also carries the transfer ID and object path, followed by a string indicating
the result of the operation, which is one of <literal>done</literal> (on success),
<literal>canceled</literal> or <literal>failed</literal>.</para>
</refsect2>
</refsect1>
<refsect1>
<title>The Transfer Object</title>
<programlisting executable="systemd-importd" node="/org/freedesktop/import1/transfer/_1" interface="org.freedesktop.import1.Transfer">
node /org/freedesktop/import1/transfer/_1 {
interface org.freedesktop.import1.Transfer {
methods:
Cancel();
signals:
LogMessage(u priority,
s line);
properties:
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly u Id = ...;
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly s Local = '...';
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly s Remote = '...';
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly s Type = '...';
@org.freedesktop.DBus.Property.EmitsChangedSignal("const")
readonly s Verify = '...';
@org.freedesktop.DBus.Property.EmitsChangedSignal("false")
readonly d Progress = ...;
};
interface org.freedesktop.DBus.Peer { ... };
interface org.freedesktop.DBus.Introspectable { ... };
interface org.freedesktop.DBus.Properties { ... };
};
</programlisting>
<!--signal LogMessage is not documented!-->
<!--Autogenerated cross-references for systemd.directives, do not edit-->
<variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.import1.Transfer"/>
<variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.import1.Transfer"/>
<variablelist class="dbus-method" generated="True" extra-ref="Cancel()"/>
<variablelist class="dbus-signal" generated="True" extra-ref="LogMessage"/>
<variablelist class="dbus-property" generated="True" extra-ref="Id"/>
<variablelist class="dbus-property" generated="True" extra-ref="Local"/>
<variablelist class="dbus-property" generated="True" extra-ref="Remote"/>
<variablelist class="dbus-property" generated="True" extra-ref="Type"/>
<variablelist class="dbus-property" generated="True" extra-ref="Verify"/>
<variablelist class="dbus-property" generated="True" extra-ref="Progress"/>
<!--End of Autogenerated section-->
<refsect2>
<title>Methods</title>
<para>The <function>Cancel()</function> method may be used to cancel the transfer. It takes no
parameters. This method is pretty much equivalent to the <function>CancelTransfer()</function> method
on the <structname>Manager</structname> interface (see above), but is exposed on the
<structname>Transfer</structname> object itself instead of taking a transfer ID.</para>
</refsect2>
<refsect2>
<title>Properties</title>
<para>The <varname>Id</varname> property exposes the numeric transfer ID of the transfer object.</para>
<para>The <varname>Local</varname>, <varname>Remote</varname> and <varname>Type</varname> properties
expose the local container name of this transfer, the remote source (in case of download: the URL, in
case of import/export: a string describing the file descriptor passed in), and the type of operation
(see the Manager's <function>ListTransfer()</function> method above for an explanation of the possible
values).</para>
<para>The <varname>Verify</varname> property exposes the selected verification setting and is only
defined for download operations (see above).</para>
<para>The <varname>Progress</varname> property exposes the current progress of the transfer as a value
between 0.0 and 1.0. To show a progress bar on screen we recommend to query this value in regular
intervals, for example every 500 ms or so.</para>
</refsect2>
</refsect1>
<refsect1>
<title>Examples</title>
<example>
<title>Introspect <interfacename>org.freedesktop.import1.Manager</interfacename> on the bus</title>
<programlisting>$ gdbus introspect --system \
--dest org.freedesktop.import1 \
--object-path /org/freedesktop/import1
</programlisting>
</example>
<example>
<title>Introspect <interfacename>org.freedesktop.import1.Transfer</interfacename> on the bus</title>
<programlisting>$ gdbus introspect --system \
--dest org.freedesktop.import1 \
--object-path /org/freedesktop/import1/transfer/_1
</programlisting>
</example>
</refsect1>
<refsect1>
<title>Versioning</title>
<para>These D-Bus interfaces follow <ulink url="http://0pointer.de/blog/projects/versioning-dbus.html">
the usual interface versioning guidelines</ulink>.</para>
</refsect1>
</refentry>