Provided by: systemd_249.11-0ubuntu3.12_amd64 
NAME
org.freedesktop.import1 - The D-Bus interface of systemd-importd
INTRODUCTION
systemd-importd.service(8) 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 systemd-nspawn(1) to run local
containers. The service is used as the backend for machinectl pull-raw, machinectl pull-tar and related
commands. This page describes the D-Bus interface.
Note that systemd-importd.service(8) is mostly a small companion service for systemd-machined.service(8).
Many operations to manipulate local container and VM images are hence available via the systemd-machined
D-Bus API, c.f. org.freedesktop.machine1(5).
THE MANAGER OBJECT
The service exposes the following interfaces on the Manager object on the bus:
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 { ... };
};
Methods
ImportTar() and ImportRaw() import a system image and place it into /var/lib/machines/. 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 ImportTar() is used the file descriptor should
refer to a tar file, optionally compressed with gzip(1), bzip2(1), or xz(1). systemd-importd will detect
the used compression scheme (if any) automatically. When ImportRaw() 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 /var/lib/machines/. A tar import is placed as a directory tree or a
btrfs(8) subvolume below /var/lib/machines/ under the specified name with no suffix appended. A raw
import is placed as a file in /var/lib/machines/ with the .raw suffix appended. If the force 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 read_only 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 org.freedesktop.import1.Transfer
object, see below. Listen for a TransferRemoved 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.
ExportTar() and ExportRaw() 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 "uncompressed", "xz", "bzip2" or "gzip", depending on which
compression scheme is required. The image written to the specified file descriptor will be a tar file in
case of ExportTar() or a raw disk image in case of ExportRaw(). 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
ImportTar() or ImportRaw() as described above.
PullTar() and PullRaw() 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 "http://" or "https://" 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 ImportTar() and ImportRaw() methods
above. The third argument indicates the verification mode for the image. It may be one of "no",
"checksum", "signature". "no" turns off any kind of verification of the image; "checksum" looks for a
SHA256SUM file next to the downloaded image and verifies any SHA256 hash value in that file against the
image; "signature" does the same but also tries to authenticate the SHA256SUM file via gpg(8) first. The
last argument indicates whether to replace a possibly pre-existing image with the same local name (if
"true"), or whether to fail (if "false"). Like the import and export calls above, these calls return a
pair of transfer identifier and object path for the ongoing download.
ListTransfers() 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 "import-tar", "import-raw", "export-tar",
"export-raw", "pull-tar" or "pull-raw"), 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.
CancelTransfer() may be used to cancel an ongoing import, export or download operation. Simply specify
the transfer identifier to cancel the ongoing operation.
Signals
The TransferNew 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.
The TransferRemoved 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 "done" (on success), "canceled" or "failed".
THE TRANSFER OBJECT
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 { ... };
};
Methods
The Cancel() method may be used to cancel the transfer. It takes no parameters. This method is pretty
much equivalent to the CancelTransfer() method on the Manager interface (see above), but is exposed on
the Transfer object itself instead of taking a transfer ID.
Properties
The Id property exposes the numeric transfer ID of the transfer object.
The Local, Remote and Type 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 ListTransfer() method above for an explanation of the
possible values).
The Verify property exposes the selected verification setting and is only defined for download operations
(see above).
The Progress 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.
EXAMPLES
Example 1. Introspect org.freedesktop.import1.Manager on the bus
$ gdbus introspect --system \
--dest org.freedesktop.import1 \
--object-path /org/freedesktop/import1
Example 2. Introspect org.freedesktop.import1.Transfer on the bus
$ gdbus introspect --system \
--dest org.freedesktop.import1 \
--object-path /org/freedesktop/import1/transfer/_1
VERSIONING
These D-Bus interfaces follow the usual interface versioning guidelines[1].
NOTES
1. the usual interface versioning guidelines
http://0pointer.de/blog/projects/versioning-dbus.html