Provided by: systemd-container_256.5-2ubuntu3.1_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 disk
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 importctl pull-raw, importctl 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);
ImportTarEx(in h fd,
in s local_name,
in s class,
in t flags,
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);
ImportRawEx(in h fd,
in s local_name,
in s class,
in t flags,
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);
ImportFileSystemEx(in h fd,
in s local_name,
in s class,
in t flags,
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);
ExportTarEx(in s local_name,
in s class,
in h fd,
in s format,
in t flags,
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);
ExportRawEx(in s local_name,
in s class,
in h fd,
in s format,
in t flags,
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);
PullTarEx(in s url,
in s local_name,
in s class,
in s verify_mode,
in t flags,
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);
PullRawEx(in s url,
in s local_name,
in s class,
in s verify_mode,
in t flags,
out u transfer_id,
out o transfer_path);
ListTransfers(out a(usssdo) transfers);
ListTransfersEx(in s class,
in t flags,
out a(ussssdo) transfers);
CancelTransfer(in u transfer_id);
ListImages(in s class,
in t flags,
out a(ssssbtttttt) images);
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()/ImportTarEx() and ImportRaw()/ImportRawEx() import a disk image and place it into the image
directory. 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()/ImportTarEx() 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()/ImportRawEx() 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 the image
directory under the specified name with no suffix appended. A raw import is placed as a file in the image
directory with the .raw suffix appended. In case of ImportTar()/ImportRaw(), 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. The read_only argument controls whether to
create a writable or read-only image. In case of ImportTarEx()/ImportRawEx() these boolean flags are
provided via a 64bit flags parameter instead, with bit 0 mapping to the force parameter, and bit 1
mapping to read_only. The class parameter specifies the image class, and takes one of "machine",
"portable", "sysext", "confext". All four 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()/ExportTarEx() and ExportRaw()/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()/ExportTarEx() or a raw disk image in case of
ExportRaw()/ExportRawEx(). 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, similarly to ImportTar()/ImportTarEx() or
ImportRaw()/ImportRawEx() as described above. ExportTarEx()/ExportRawEx() expect the image class as
additional parameter, as well as a 64bit flags parameter that currently must be specified as zero.
PullTar()/PullTarEx() and PullRaw()/PullRawEx() may be used to download, verify and import a system image
from a URL. They take a 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, similarly to the matching argument of the
ImportTar()/ImportTarEx() and ImportRaw()/ImportRawEx() 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. In case of PullTar()/PullRaw() 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"). In case of PullTarEx()/PullRawEx() the last argument is a 64bit flags
parameter, where bit 0 controls the "force" flag, bit 1 is a "read_only" flag that controls whether the
created image shall be marked read-only, and bit 2 is a "keep_download" flag that indicates whether a
pristine, read-only copy of the downloaded image shell be kept, in addition for the local copy of the
image. The ..._Ex() variants also expect an image class string (as above). Like the import and export
calls above, these calls return a pair of transfer identifier and object path for the ongoing download.
ImportFileSystem()/ImportFileSystemEx() are similar to ImportTar()/ImportTarEx() but import a directory
tree. The first argument must refer to a directory file descriptor for the source hierarchy to import.
ListTransfers()/ListTransfersEx() return a list of ongoing import, export or download operations as
created with the six calls described above. They return 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, the image class
(only in case of ListTransfersEx(); one of "machine", "portable", "sysext", "confext"), 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.
ListImages() returns a list of currently installed images. It takes a image class string and a flags
parameter. The image class is either the empty string or specifies one of the four image classes, by
which it will then filter. The flags parameter must be zero at this time. It returns an array of items,
each describing one image. The item fields are in order: the image class, the local image name, the image
type, the image path, the read-only flag, the creation and modification times (in microseconds since the
UNIX epoch), as well as the current disk usage in bytes (both overall, and exclusive), as well as any
size limit in bytes set on the image (both overall and exclusive).
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);
ProgressUpdate(d progress);
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.
Signals
The LogMessage() signal is emitted for log messages generated by a transfer. It carries a pair of syslog
log level integer and log string.
The ProgressUpdate() signal is emitted in regular intervals when new download progress information is
available for a transfer. It carries a double precision floating pointer number between 0.0 and 1.0
indicating the transfer progress.
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].
HISTORY
The Manager Object
ImportTarEx(), ImportRawEx(), ImportFileSystemEx(), ExportTarEx(), ExportRawEx(), PullTarEx(),
PullRawEx(), ListTransfersEx(), ListImages() were added in version 256.
Transfer Objects
ProgressUpdate() was added in version 256.
NOTES
1. the usual interface versioning guidelines
https://0pointer.de/blog/projects/versioning-dbus.html